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  Information and Modifications for the MSR2000 station
Compiled by Mike Morris WA6ILQ
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This page is a work in progress... Your help is needed.

If anyone would like to contribute a mod article, a tuneup tip, photos of the missing boards, or internal photos of the intermittent and continuous duty PA decks, or internal shots of the different power supplies, we'd appreciate them.
Remember, these pages are what YOU make of them.




Photo 1: A dual receiver wireline controlled MSR2000 continuous duty station.
The exciter and receiver card(s) are behind the panel above the horizontal cards.
The empty horizontal slot at the top left is for the "coded squelch" card (either PL or DPL).
The rightmost (double wide) vertical card is the line driver, the card to the left of it is the station control card.
The three cards in the center are usually used only in tone controlled wireline systems.
Models with an in-cabinet duplexer are in a taller cabinet, with the duplexer at the bottom.
MSR indoor cabinets are 21 inches wide, 10 inches deep, and come in multiple heights.
The one in the photo above is 32 inches high.
Click on the image above for a larger image (576KB).   Photos by Tim Ahrens W5FN



Photo 2: A view of the exciter and receiver card(s). From the left is the exciter, the second receiver and the primary receiver.
Most MSRs do not have the second receiver, and would have an empty center horizontal slot.
Both a single receiver base station and a repeater station will usually be missing the connector for the second receiver.
There are at least two different backplanes used - simplex, duplex, with the horizontal card slots and without.
Click on the image above for a larger image (457KB).   Photos by Tim Ahrens W5FN


Note: Any Motorola prices mentioned on this page (or on any page at this web site) should be taken only as a rough guideline. Motorola adjusts prices quarterly, and offers one set of prices to their dealers/service shops (the so called "NSO" Pricing ("National Service Organization")), another to "self-maintaining" fleet customers (i.e. those that have their own radio shops... cities, counties, police departments, fire departments, etc) and a third on their telephone order desk (i.e. retail sales).   For these reasons readers should use the prices mentioned in an article only as a rough indication.   We'd appreciate an emailed update if you discover a major price change.

The MSR2000 is a base or repeater station that was a follow-on to the Micor line, and was available only in high band VHF and UHF. It is the last non-synthesized base station made, and is basically a second-generation Micor station control shelf mated to separate receiver and exciter modules that are derived from the Mitrek mobile. The exciter drives a Micor-derived PA deck.

The station shelf has a few upgrades (like the horizontal slots at the top, and a new, more reliable style of card-to-backplane connector). The control card cage is almost identical to a Micor and most of the notes on the Micor station control shelf are applicable. If you replace the card edge connectors that mate with the Micor backplane with ones made for the MSR you can use several of the Micor cards in the MSR card cage - BUT NOT ALL.   Compare the function of each pin and the polarity of the signal before you go to the trouble of changing the connectors.

Both the receiver and exciter modules use a frequency-determining component called a Channel Element. This is a self-contained oscillator-tripler plug-in module, and there is one element for the receiver and a separate one for the exciter.   The exciter element contains the modulator.   When you move an MSR from one frequency to another it requires swapping the Channel Element for one on the new frequency, or changing the frequency of the Channel Element by replacing the internal crystal with a new crystal for the new frequency.   This article is worth reading: Why should you really should spend $50 to re-crystal a channel element.

A list of the various channel elements used in the MSR station and the Mitrek mobile is here: Channel elements for the Mitrek and MSR2000.

As far as I can tell from the manuals, the model number structure on the USA-built MSR2000s breaks down as:

Sample model number: C74GSB-3106BTX         Numbers in ( ) refer to notes below.
C 7 4 G S B
Cabinet
Type (1)
Power
Level
Frequency
Band (2)
Duty
Cycle (3)
Configuration (4) Supply
Voltage (5)
B
Base
Station
Cabinet
5
40-70 watts
3
VHF
G
Intermittent
R
Base Station
(no duplex shield kit, has the base station backplane)
A
+12vDC
(rare)
C
Compact
Cabinet
6
70-90 watts
4
UHF
K
Continuous
S
Repeater (has the duplex shield kit and duplex backplane)
B
120vAC
N
No
Cabinet
7
90-120 watts
K
120v or 240vAC

Sample model number: C74GSB-3106BTX         Numbers in ( ) refer to notes below.
3 1 0 6 B T X
Squelch
Type (6)
Channel
Deviation (7)
Frequencies (8) Control (9) Hardware
Version
Configuration (10) (?) (11)
1
Carrier
0
15 KHz
0
Single Frequency
3
Local Only
A A
(?)
X
(?)
3
PL
1
5 KHz
3
Two Frequency
5
DC Wireline
B B
Base
6
DPL
9
Four Frequency
6
Tone Wireline
C D
(?)
7
(?)
D T
Repeater
If anyone would like to contribute any information on how the model numbers for the Canadian-built units are different just let Mike WA6ILQ know.

Table Notes:

  1. An "N" is a very rare beast, as they were special order. It was actually cheaper (and quicker) to order a "C" model and remove it from the cabinet (which could be sold to someone else). There was also a version that was built for open frame relay racks and use several different mechanical parts than those that were built for cabinet racks, and not all of those parts are covered in the manuals.
  2. The frequency range (the "split") is not encoded into the MSR2000 model number. To determine if you have a (for example) 132-150 MHz or a 146-174 MHz station you will need to look at the part number of a frequency determining part, like the exciter, receiver, or PA deck.   A table of all of the exciters and the receivers that I know of is below. Note that the high band receivers and exciters come in two splits and the PA comes in three splits (136-150, 150-162, and 162-174  MHz). It is NOT practical to change splits on a PA (VHF or UHF).
  3. There is no practical way to change an intermittent duty cycle radio to a continuous short of replacing the power supply, the PA deck and the antenna relay (if equipped, and needed). By the way, Moto does not call it a relay, they call it an "antenna switch".
  4. The MSR manual refers to the GS series models as the "Fully Optionable" models. There is no practical way to convert a base to a repeater with full performance as the repeat duplex kit includes a different backplane, a different receiver, a different exciter and a different PA deck, plus some additional metal shield plates. Yes, the MSR2000 Base can be converted for duplex repeat operation, it's just that something designed and built to run full duplex from the factory is going to be better. It's much easier if you have the duplex (repeater) backplane, which is the one with the PL and R1-Audio Modules laying horizontal above the main module slots. And there were repeater, one-receiver and two-receiver backplanes. Only the factory repeaters were shipped with the duplex backplanes.
  5. The  A  power supply was essentially a 120v AC supply minus the power transformer and bridge rectifier - essentially just a robust DC filter and a 9.6 regulator. The  K  power supply was made in Canada and was extremely rare in the USA. I've only seen one of them.
  6. Changing squelch types involves changing out the squelch card (or adding one if you have a carrier squelch station) and changing some jumpers. See the  PL  section below.
  7. These units were built in the era when  wideband  was +/- 15 KHz, and  narrowband  radio was +/- 5 KHz. A  0  is a very rare beast as the market for wideband radios was very limited. It was a special order unit, and the major customers for them was the broadcast industry as some stations still had wideband VHF and UHF remote pickup channels at the time the MSR stations were current products. If Moto offered a modern day narrowband (+/- 2.5 KHz) MSR this column would have a  2  option, but to my knowledge they never did.
  8. The exciters and recivers were all built for four frequency operation, the difference in the station was the number of channel elements that were included and the complement of the cards in the control shelf.
  9. I've seen one  7  unit, and could not figure out what the difference was. If anybody has any information on it I'd appreciate it. It wouldn't have been the first typo on the factory model plate that I've seen.
  10. Does anybody have any information on the  A  or  D  configurations?
    If you have a  B  unit (a base) and are converting it into a repeater you really, really want to remove the "antenna switch" (the antenna relay). Some folks just disconnect the antenna relay coil wires, use the original connector as the receive antenna and add a new transmit antenna connector cabled to the PA deck ooutput. Others recable the receiver to a separate antenna jack and leave the PA deck feeding the antenna relay feeding the original antenna jack (which they use as the transmitter jack). This works fine until the antenna relay fails and leaves the PA deck with no load... and the relays will fail eventually. Do yourself a favor and remove the antenna relay and install separate receie and transmit antenna connectors.
  11. The manual does not explain the  X , and I've seen two MSRs that had the  X  at the end of the model number and could not figure out what the difference was. Can anyone shed some light on the topic?

The Model Tables, Option Tables and Specifications from the 6881061E50-C VHF manual   1.7 MB PDF file
From these tables you can fully decode the cabinet model number and figure out what your station was originally shipped with. Note that the full manual PDF is available below.

Carrier Squelch, PL and DPL:

As said above, changing squelch types involves changing out the PL or DPL squelch card (or adding one if you have a carrier squelch station) and rearranging some jumpers. There are three different PL cards,and three different DPL cards.
In all cases the receiver audio path starts at the receiver slot, then goes to the R1 audio card, then to the PL or DPL card, then back to the R1 audio card.   Both the PL and DPL cards have an on-board high pass / low cut audio filter that removes the PL or DPL frequencies.   If you have no audio in your surplus MSR2000 and an empty PL / DPL card slot then you need to insert (add) the JU1 jumper on the R1 audio card to bypass the missing audio filter on the missing PL or DPL card.
Note that if you have a second receiver in your station that there were three different second receiver control boards (commonly called the R2 board), one for carrier squelch applications, a second for PL squelch applications and a third for DPL squelch applications.

All three PL cards were built from the same bare PC board, the difference was the parts complement and the jumpers on the card.   The TRN5074 and TRN5075 were intended for base stations where the TRN5073 (click for a photo) is the duplex PL board you need for repeater service as it supports simultaneous PL decode and encode.   The documentation refers to the TRN5704 and TRN5705 as "simplex" PL boards (in this usage simplex means that the board can either encode during transmit or decode during receive, but not both at the same time).   The TRN5074 is a single-reed card that forces you to use the same tone on receive and on transmit.   The TRN5075 board (click for a photo) is a dual reed simplex board that can alternately do split tones (i.e. encode one tone and decode another tone).

Conversion of the TRN5074 or TRN5075 to a TRN5073 is straightforward.   Print off the schematic, parts list and parts layout for the TRN5073 board, and the one for your TRN5074 or TRN5075.   Acquire the parts.   Suck out the solder from the holes, install the missing parts. Test and install.

We'd be happy to host a conversion article if anyone would like to shoot a set of photos as they convert a card.

As to the tone reeds themselves, the parts list for all three PL boards calls for a KLN6209A reed as the decode reed and a second KLN6209A as the encode reed.   My own personal experience (hams tend to be experimenters) shows that a KLN6210A reed will work - and this implies that a TLN6824A will also work.   The early Micor mobile manuals specified a TLN6824A as the encode reed and the later Micor mobile manual showed the KLN6210A reed.   According to an engineer at Motorola in El Segundo California the KLN6210A and the TLN6824A are essentially the same reed, the TLN6824 is the older design with a metal case and the KLN6210 is the newer cost-reduced model with a plastic case.   I've interchanged 6209s and 6210s out in the field and not noticed any difference.   I've also used a leftover K-1000 reed from an old Com-Spec decoder and not noticed any difference.

If the customer needed multiple tone PL decode or encode in their MSR station Moto put a TRN53259A card in the otherwise empty tone burst decoder position (slot 11) on the left side of the card cage.   A matching multiple tone encode card went into slot 12.   These two cards use different reeds (TLN6824A or KLN6210A for the encoder, TLN8381A in the decoder).   A "Matrix" card went in a third slot and allowed the tone remote system to control the encode and decode characteristics.
If you need multiple tone and can't find a real Moto card you can home-brew your own with one or more TS-32s or TS-64s mounted on a card (a timeout timer makes a good candidate to be stripped and recycled in this way).

As to DPL, again there are three boards, all based on the same bare PC board.   The TRN5076 is the duplex DPL board, the TRN5077 is the single code simplex DPL board and the TRN5078A is a simplex board that can do split codes. Here's a photo of a DPL board. The vertical blue bar that is next to the large chip at the top is a TRN6005 code plug.   There is an article on this web site on how to make your own code plugs.   The particular system that the DPL board in the photo came out of was DPL receive and carrier transmit, hence the lower code element socket (J100) in the photo is empty.

Again, we'd be happy to host a conversion article if anyone would like to shoot a set of photos as they convert a card.

Station Notes

VHF Low Band (30-50 MHz) or Mid Band (66-88 MHz)
As far as I know, there never was a MSR2000 on low band (30-50 MHz), mid band (66-88 MHz), 800 or 900 Mhz.
I believe that if a customer needed one Moto sold them a Micor station.


VHF High Band (132-174 MHz) Exciters
Model number
(plus A or B suffix)
(see note)
Frequency
MHz
Filtering
(see note)
Mode Module
Connector
Notes
TLD9231 132-150.8 No Simplex Female  
TLD9232 146-174 No Simplex Female TLD9232BPR top photo
TLD9232BPR bottom photo
both by Tim Ahrens W5FN
TLD9241 132-150.8 Yes Duplex Male  
TLD9242 146-174 Yes Duplex Male TLD9242B top photo
TLD9242B bottom photo both by WA6ILQ
All VHF exciters in 0.0005% service used the KXN1088 Channel Element.
Those used in 0.0002% service used the KXN1095 Channel Element.
The manuals that this information came are from my files, and are early versions.
I know that there are additional exciters that were developed after my manuals were printed.
If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can supply any of the missing photos we'd appreciate it.


VHF High Band (132-174 MHz) Power Amplifiers
Model number
(see note)
Frequency
MHz
Power Duty Notes
TLD2532A 150.8-162 60-110 Intermittent  
TLD2601 132-150.8 50-100 Continuous  
TLD2602 150.8-162 50-100 Continuous  
TLD2603 162-174 50-100 Continuous  
The manuals that this information came are from my files, and are early versions.
I know that there are additional intermittent duty amplifiers, plus several continuous duty power amplifiers that were developed after my manuals were printed, plus there are Canadian-specific amplifiers.
If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can supply photos we'd appreciate it.


VHF High Band (132-174 MHz) Receivers
Model number
(plus A or B suffix)
(see note)
Frequency
MHz
I.F. Frequency
(see note)
Filtering
(see note)
Mode Module
Connector
Notes
TRD6171 132-150.8 10.7 MHz No Simplex Female  
TRD6172 146-174 10.7 MHz No Simplex Female  
TRD6181 132-150.8 10.7 MHz Yes Duplex Female  
TRD6182 146-174 10.7 MHz Yes Duplex Female TRD6182A top photo
TRD6182A bottom photo
both by WA6ILQ
TRD6191 132-150.8 10.7 MHz No Duplex Female  
TRD6192 146-174 10.7 MHz Yes Duplex Female  
TRD6301 132-150.8 10.7 MHz Yes Duplex Female  
TRD6302 146-174 10.7 MHz Yes Duplex Female TRD6302APR top photo
TRD6302APR bottom photo
both by Tim Ahrens W5FN
TRD6311 132-150.8 10.8 MHz Yes Duplex Female  
TRD6312 146-174 10.8 MHz Yes Duplex Female  
The TRD7171 / 72 are used with single receiver non-repeat (non-duplex) stations.
The TRD6181 / 82 and the TRD6301 / 02 are normally used with either two-receiver stations or on repeater (duplex) stations.
The TRD6191 / 92 and the TRD6311 / 12 are used with 2-receiver and repeater (duplex) stations where a shifted IF is required.
All of these receivers can be configured for up to 4 frequencies, but no more than 2 MHz from lowest to highest frequency.
All VHF receivers in 0.0005% service used the KXN1086 Channel Element. Those used in 0.0002% service used the KXN1112 Channel Element.
The manuals that this information came are from my files, and are early versions.
I know that there are additional receivers that were developed after my manuals were printed.
If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can add the missing photos we'd appreciate it.


UHF (406-512 MHz) Exciters
Model number
(plus A or B suffix)
(see note)
Frequency
MHz
Filtering
(see note)
Mode Module
Connector
Notes
TLE ? 406-420 ? Simplex ?                                       
TLE ? 406-420 ? Duplex ?  
VTE4001A 406-420 Yes Duplex Male VTE4001A top photo
VTE4001A bottom photo
both by VE2TSO
TLE5502 450-512 No Simplex Female  
TLE5512 450-512 Yes Duplex Male  
All UHF exciters in 0.0005% service used the KXN1088 Channel Element, just like the VHF ones.
Those used in 0.0002% service used the KXN1095 Channel Element.
The VTE-series exciters were shipped only in the Canadian-built stations for use in Canada.
The manuals that this information came are from my files, and are early version USA manuals.
I know that there are additional exciters that were developed after my manuals were printed (for example, those on 406-420 MHz).
If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can supply the missing photos we'd appreciate it.


UHF (406-512 MHz) PA Decks
Model number
(plus A or B suffix)
(see note)
Frequency
MHz
Power
Watts
Notes
TLE2283 450-494 45-100  
TLE2284 494-512 45-85 Will not work on 440-450 MHz Amateur Radio or on 462 MHz GMRS
The manuals that this information came are from my files, and are early version USA manuals.

There are other USA models that I do not have here (for example, those on 406-420 MHz) plus there are the Canadian-only models.

If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can supply photos we'd appreciate it.


UHF (406-512 MHz) Receivers
Model number
(plus A or B suffix)
(see note)
Frequency
MHz
I.F.
Frequency
(see note)
Filtering
(see note)
Mode Module
Connector
Notes
TRE ? 406-420 10.7 MHz ? Simplex ?  
TRE ? 406-420 10.7 MHz ? Duplex ?  
VRE4001A 406-420 ? Yes Duplex Female VRE4001A top photo
VRE4001A bottom photo
both by VE2TSO
TRE6152 450-470 10.7 MHz No Duplex ?  
TRE6153 470-512 10.7 MHz No Simplex ?  
TRE6162 450-470 10.7 MHz Yes Duplex Female  
TRE6163 470-512 10.7 MHz Yes Duplex Female  
TRE6172 450-470 10.8 MHz Yes Duplex Female  
TRE6173 470-512 10.8 MHz Yes Duplex Female  
TRE6262 450-470 10.7 MHz Yes Duplex Female TRE6262A top photo
by WA6ILQ
TRE6263 470-512 10.7 MHz Yes Duplex Female  
TRE6272 450-470 10.8 MHz Yes Duplex Female  
TRE6273 470-512 10.8 MHz Yes Duplex Female  
The TRE6162 and 63 are the most common receivers. The TRE6172 is used where a shifted IF is required (i.e. 2-receiver stations). All of these receivers can be configured for up to 4 frequencies, but no more than 2 MHz from lowest to highest frequency.
A quick way to tell what split of UHF receiver you have in your hand: If the UHF preselelector part number ends in "D56" you have a 450-470 MHz unit, if it ends in "D57" then you have a 470-512 unit.
All UHF receivers in 0.0005% service used the KXN1086 Channel Element just like the VHF receivers.
Those used in 0.0002% service used the KXN1112 Channel Element.
The VRE-series receivers were shipped only in the Canadian-built stations for use in Canada.
The manuals that this information came are from my files, and are early version USA manuals.
I know that there are additional receivers that were developed after my manuals were printed (for example, those TRE-series on 406-420 MHz).
If anyone has additional model numbers that should be in this list but are not just email me the information and I'll add them.
If anyone can add the missing photos we'd appreciate it.

More notes:

  • There are at least three different vhf high band power amplifier models... the 110 watt inttermittent duty power amplifier works pretty well at about 60 watts continuous duty in a well vented and cooled radio vault, but you need to add fans, and if they die so does the power amplifier.   The continuous duty rated amplifier deck will do continuous duty only if it is operating in the proper band segment for which it was built.   And the range change / conversion parts are no longer available from Moto.
  • An easy to tell if you have the intermittent or the continuous duty amplifier: if yours has heatsink fins all the way across the rack panel, you have the continuous duty PA.   If the fins only go about halfway across, it's the intermittent duty PA.

    This is the continuous duty power amplifier


    This is the intermittent duty power amplifier

  • If you have the intermittent duty amplifier, use two fans, and mount a normally open Klixon-type snap-action thermostatic switch to the hot end of the heat sink, and wire it such that when activated it turns on the spare fan and also trips an alarm on your repeater controller (maybe the courtesy tone changes from a single dit to a Morse "H" (for Hot) and the MCW ID gets a "(space)OT" for OverTemp added to the end).   Or something.   Look at the fan segment of the Mitrek Mobile Interfacing document for a diagram on how to use one thermostat for both functions.


    This is one way to fan cool an intermittent duty amp.

  • The early "A" versions of the PA (those that had a part number of the format like TLD2602A and ending with "A") would fail if you looked at it cross-eyed.   The later version that had the part number ending with a "B" was much improved and could better deal with reactive loads and heat problems.   If you are going to buy an MSR, you really, really want to avoid the "A" version PA decks.
  • UHF PA's were built in three band segments.   There's the low split "government range" version on 406-430 MHz, there's the 450-490 MHz range, and there's the high range 485-512 MHz range.   And there is no way of changing a 406-430 or a 485-512 to 450-490.
  • If your MSR came with an antenna relay in it then that's a pretty good indication that it was set up as a base station.   If you are converting it to a repeater you will have to remove (or bypass) the relay plus go through the entire station and move jumpers around to make it a duplex station.   This procedure requires both the RF and the C&A manuals to get all the jumpers.   One jumper that many folks miss is JU-101 on the receiver card... it sets the receiver to be on continuously.   If your unit was originally set up as a base station then JU-101 will probably be missing.
  • The MSR station has been known for developing intermittents in the blackplane if a connector pin is bent and then straightened (the force used to bend and then straighten the pin frequently cracks the solder).   This is especially true on audio connections - the symptoms are that the audio level can wander, become distorted and suddenly clear itself up, etc.
    The fix is simple and permanent: Assume that any pin that has been bent (and then straightened) on any card slot will have to be resoldered.   Use a good strong magnifying glass (or a set of binocular magnifiers) and check every bent pin on the card socket for cracks between the pin and the solder or between the solder and the trace.   On any that are suspicious use a flat toothpick to dab a tiny bit of flux on the surface of the solder then reflow it using a long thin soldering tip.   This is also true of the pins on the receiver, exciter and PL board.
  • The MSR2000 station does not have a power on indicator.   One common mod to the station control card is to add a green LED (labeled, naturally, POWER) and an appropriate series resistor across the +12vDC buss to ground.
  • Do yourself a favor - replace the deviation set potentiometer (the "IDC Control") in the exciter with a sealed unit before you put the unit in service, especially if it is going to a mountaintop, an elevator room, or otherwise in a dirty environment.   The stock potentiometer is an open PCB-mounted unit and has a tendency to get dirty and cause erratic transmitter audio over time.   If you plan on running a carrier squelch receiver then replace the squelch pot in the R1 audio card as well.   Personally I'd mount a real squelch potentiometer into the faceplate of the card.   See the note below about the Micor Aux Receiver card volume control replacement.
  • The chassis metering jack(s) is(are) on the BACK of the card cage, and you have to tilt it down and forward so the metering plug is inserted from the back of the back plane.   Not through the PL board slot.
  • The "official" MSR test set is the TRN5080A or B, but you can use the standard portable test set (TU546 or S1056) with the correct cable. Note that the "correct" cable is the Micor cable PLUS an adapter cable. See the Motorola Test Set page at this web site for more details.   Here are several photos of the TRN5080 series test set:
    front     rear     left side     right side     group photo
    You can download the manual for the TRN5079 and TRN5080 here (it's just the three pages extracted from the 6881061E50C service manual files).
  • The MSR2000 station does not have a built in speaker - it's either in a small box that plugs into the backplane (TRN5079), or it's part of the test set (TRN5080).   You can connect a regular 8 ohm mobile speaker with no problems.   Just plug it onto the pins labeled "Speaker".   The speaker is on the R1 Audio card slot card slot pins 22 and 23 (look in the lower right corner). If you are at a shared site please be a good neighbor and switch the speaker off when you aren't there. The techs servicing the adjacent rack will appreciate it.
  • The official multi-PL tone decoder module for the card cage is the TRN5329A or TRN5329B.   When used in the stock repeat shelf, this card allows the repeater to respond to up to four tones on the receiver input, ORed on the card to the single status line that tells the control shelf that the PL tone has been decoded.   With the MSR configured as a full duplex base station, and cabled to a repeater controller, it can feed the repeater controller inputs and tell it which tone is being received.   One common use of multiple tone decode is on a club machine, with the first tone (for example, 100 Hz) listed in the local repeater directory, and a second tone (perhaps 146.2 Hz) used by club members.   You would program the repeater controller so that the 100 Hz tone would provide local repeat, and the 146.2 Hz could allow autopatch, remote base, IRLP, and other system toys.   Installing this card does not preclude any other options as it slides into the otherwise unused tone burst decoder slot.   Click here for a photo.   Click here for the manual, 2.03 MB.   The equivalent card for the Micor station is the TLN5745A or TLN5745B Multi-PL Decoder.
  • If you need to make up a custom card for your system the Timeout Timer card (click here for a photo) is a good candidate to get stripped, then mount a piece of perfboard on it using some standoffs, and build your trick circuit on the perfboard.   I saw one where the gentleman made up his own multi-PL decoder card for the tone burst decoder slot by stripping a timeout timer card and mounting two Com-Spec TS-32s on it using double sided foam tape. A small piece of perfboard on standoffs held the interfacing components and the logic that ORed the two PL decode outputs.
  • Barry Sloan VE6SBS of Alberta Canada modified serveral MSR200 cards as part of the VE6NHP system upgrade.   His modifications are worth looking at and possibly copying into your system.   Full documentation is in an article linked below - see "Modifications to the MSR2000 cards by VE6SBS for the VE6NHB repeater".
    The mods included:
    1) The R1 card: Squelch circuitry was modified to reduce the noise squelch threshold when PL tone encoded signals are received.
    2) The R1 card: Adding a COS indicator and a squelch indicator.
    3) The station control card: Adding a PTT indicator and both PL disable and TX disable indicators.
    4) The PL card: Added PL decoder and encoder indicators, plus a transmit PL encoder disable switch.
    5) New homebrew card: An AC Fail and Battery Control circuit was developed and built on a card and wired to switch the repeater over to 12 volt DC battery operation upon loss of AC mains power.   The circuit also adds a low level beep tone to transmissions while operating on battery power to indicate battery operation and the loss of AC power or power supply problems.
  • The local speaker volume control affects only the local monitor speaker.   It is a screwdriver adjust accessed through a hole in the control card metal endpiece.   One very common modification is to replace that potentiometer with one that has a real shaft and a regular knob. One good candidate is from Mouser, part number 774-270X232A253B2A1 (25K audio taper) at under US$3. A matching knob is Mouser p/n 506-PKG40B1/8 that will run about US$1.55 (both the pot and the knob are 1/8 inch shaft parts).   If your R1 card has the Intercom option you will have to use the original hole, if not then the new pot can be mounted into a new hole in the endplate on the opposite side of the "VOL" label.   Either way, you then run three jumper wires from the terminals on the new pot to the circuit board where the connections from the original pot used to terminate.   See this article for a similar mod to a Micor Aux Receiver card.
  • While the documentation calls for a TMN6057A handset or a TMN6054A hand microphone you can plug almost any regular Mitrek / Micor / Syntor mobile microphone into the front of the TRN5069 receiver control card (click here for a photo) to provide local keying and local microphone audio.   The station audio card has the microphone audio mix function built in.   Just mount a mobile mic clip to the chassis and you are done.   Since the standard mobile mic has a set of normally open switch contacts in series with the element you won't be picking up any in-cabinet noise if you leave the microphone plugged in.


    The above photo illustrates the last two points. And yes, in this photo the card is on an angle because the left hand card guide is missing.
  • So if you are looking for a used MSR repeater the ideal station is a xnnKSB-31xxBT, CT or DT series (where "x" is the appropriate letter and "n" is the appropriate number), and a GSB series will do just fine at reduced power and a with an added fan.   And if you end up with a GSB series you really want to mount a second (backup) fan controlled by a thermostat.

    By the way, after alignment of the receiver consider removing S201 (a rubber membrane type switch) on the receiver board if your receiver has one.   It has been known to short and cause dead receiver symptoms.   This is especially important if you are placing the repeater in a remote location.   Personally, I replace it with a couple of pins that I can put a clip lead across when needed.   I've been known to use couple of cut-off-resistor leads left over from stuffing a PC board, soldering and then trimming the leads.

    And at some point open the harmonic filter on the PA and take a look around with a magnifying glass and take a good sniff as well... They have been known to burn internally, especially under out-of-tune conditions.

    Useful MSR2000 Tools, Manuals, etc.       Click here for instructions on how to order manuals.

    Most of the books below are NLA (no longer available), if you want a paper copy try your local 2-way shop, the repeater-builder or "Motorola-User" yahoogroups, or eBay.

    Like the predecessor, the Micor, all MSR stations have two separate manuals and some of the options have their own separate manual.   Most (if not all) MSR manuals are NLA (No Longer Available).   If you try to order one you will be told that the manual has been canceled.

    The first book that you will need to acquire is the "Control and Applications Manual", part number 6881061E40 (some literature called it the "Control and Audio" manual).   This book covers everything that is not RF frequency dependent - mostly the control shelf.   The second book you will need is the RF manual (this is frequency band dependent).   At the time of this writing (mid 2009) all of the RF manuals were out of stock (but are PDF'd below).

    To work on your base or repeater you will need BOTH the C&A Manual AND the appropriate frequency band RF manual... EXCEPT that the publications department at Moto made a major screw up... they put the power supply and accessory section into the VHF RF book.   This means that if you have a UHF station you will need to print the power supply and accessory section from the high band PDFs below, or locate a VHF book just for the power supply and accessories.

    Below we offer downloadable PDFs of the NLA manuals.   Some are presented in both a smaller file and a larger file with better resolution.   If you have the download time and the hard drive space you will want to get the bigger file.

    Note that the Canadian MSRs had some significant differences - enough that there were Canadian manuals that had significant differences from USA manuals.   One difference was that the Canadian manuals included the 40 watt PA decks that are not in the USA manuals.   If anyone would like to do a descriptive article of the differences between the USA and Canadian models we'd be happy to add it to this page.

    Another issue with the MSR manuals is that the UHF manual covers 450-512 MHz. There is another manual (or manual supplement) that covers the 406-420 MHz stations. I do not know the part number, I do not have one in my file cabinet, Moto does not list that manual on it's web site, and none of the usual suspects has one in their file cabinet.
    Needless to say, if anyone has one, please let me know. If it's still available I'd like to post the part number and price, if it's been cancelled I'd like to get a scan of it and post it here.

    Does any one have the updated info that covers the differences between the "A" and "B" versions of the VHF power amplifiers, or a manual that shows the "B" version amplifiers ?

    MSR2000 Configuration Notes, etc.

    Alingment information and notes:

    . The official MSR2000 test set is the TRN5080 series (click here for a photo) or you could use a standard Moto Test Set with the proper cable kit (see this page).
    Documentation, including schematic and parts list   Photo courtesy of David Stanford K7IOU
    Anybody have a photo of the TRN5079 test speaker ?

    One of the handiest things to have around when you are realigning or troubleshooting a radio is a logbook that lists the meter readings from when it was working properly. I really suggest that you have a station logbook that starts the day you receive the station, with the first entry noting the date, the frequencies it was on when it was received, and a complete list of every meter reading of the receiver, exciter and PA deck on the old frequencies. Then after you realign the radio to your new frequencies repeat the process on the new frequencies. Just by looking at the numbers you can figure out what stage has taken a hit and won't tune.

    The most overlooked step, and the real key to realigning the MSR2000 Receiver and Exciter modules is to follow the first pre-alignment step listed in the Service Manual: Back all the inductor (coil) cores out of their forms to the locations indicated in the chart / position table / pictures. You must do this when moving any module more than 1MHz from the old frequency. Once that step is complete then you can start your new alignment from scratch. One of the meter dip / peak indications is very, very small and easy to pass over to the next wrong position so pay very special attention to the actual meter movement as you go through the steps.

    I'm going to put this in large type: You must use an analog meter for the RF alignment. Moto made a test set specifically for the MSR2000 stations and internally it is a 50µa meter. On the voltage scales it functions as a 20,000 ohms-per-volt voltmeter. There are two good reasons for this:
    1) ALL of the metering points on radios of that era were configured to use either a 50µa meter to ground, or a 20k-ohms-per-volt meter, and the measurement circuit uses the resistance of the test meter as part of a series circuit (from the test point to ground). Without a load of the correct value none of the metering readings were meaningful.
    2) There were no inexpensive portable digital multimeters (DMMs) when these radios were being designed - every two-way tech had either a Motorola test set or a homebrew replacement, or a portable VOM (a Simpson 260, a Triplett 630 or the WW2 surplus military equivalent) that had a 50µa scale.The voltmeter scales were based on that 50µa movement which produced a 20,000-ohms-per-volt voltmeter. Modern DMMs have a input impedance that ranges from 2 to 11 megohms (depending on the manufacturer and model, most are 11 meg) and without the proper 20k-ohms-per-volt load none of the book measurement values will be correct.

    In other words, YOU CANNOT USE A MODERN DMM TO PROPERLY TUNE AN MSR2000.

    Two additional "gotchas" are that most inexpensive DMMs go crazy in the presence of RF energy due to the fact that they are sold by price, so to maximize the profit the manufacturers scrimp on the shielding, and lastly, in every case you are tuning for a peak or a dip - attempting to do that with dancing numbers on a DMM is an exercise in frustration - you are constantly trying to determine if the new number is higher or lower than the last number and your brain can't keep up with the DMM display update rate. You are tuning for a peak or a dip, you NEED an analog needle meter to see the peak or dip.

    I received an email that disagrees:

    I don't agree, in fact it's much easier for me to use my Fluke DMM to detect some of the very small meter peaks and dips. There is no rule or requirement the metering points have to be loaded by a 50uA movement.

    Erratic metering with low cost Digital Multi Meters is probably the result of the price you paid.

    "If it's a good meter, it must be a Fluke".
    Interesting - My main portable DMM is a Fluke 73. But he makes a good point. Next time I'll use the DMM in parallel with the test set and try it.

    Another key to aligning / realigning the MSR2000 Receiver and Exciter strips is to follow the first pre-alignment task item listed in the service manual: back all the inductor (coil) cores out of their forms to the locations indicated in the slug position graph.   One useful trick is to put a flap of tape on the tuning tool - not only does it help in counting turns but it also helps prevent the tool from rolling off the workbench.

    Then start your new alignment from scratch. At least one of the meter dip / peak indications is very, very small and easy to miss. If you mistune that stage nothing after it works right so pay very special attention to the actual meter needle movement as you go through the manual steps and the various stages in the receiver and exciter.

    .Alignment of the MSR2000 station VHF receiver   180 KB PDF document

    . Alignment of the MSR2000 station VHF transmitter   4.6 MB PDF file
    This covers both intermittent and continuous duty models

    .Alignment of the MSR2000 station UHF receiver   176 KB PDF document

    .Alignment of the MSR2000 station UHF transmitter   1.2MB PDF document

    Another transmitter alignment trick... have a DC ammeter in series with the PA deck as you tune the station. You are looking for best efficiency, not the absolute best power output.

    Articles:

    .Conversion of an MSR2000 station to an amateur repeater
        By Henry Wingate K4HAL
    This article includes interfacing and DIP switch settings for a CAT-200 repeater controller.

    .A status display for the MSR2000 station
        By Henry Wingate K4HAL
    VE6SBS took this idea and ran with it. He added LEDs into the faceplates of the Moto cards themselves. See the article below titled "Modifications to the MSR2000 cards by VE6SBS for the VE6NHB repeater".

    . Another conversion of an MSR2000 station to an amateur repeater
       By David Stanford K7IOU   (offsite link)
    Since Henry and his team use a CAT-250 tied to an RLS-1000 the repeater interfacing is CAT-oriented but applicable to most controller models.

    . Conversion of an MSR2000 station for the WØDOD repeater   By Nate Bargmann, NØNB
    This writeup includes connections to a Computer Automation Technology CAT-250 repeater controller. Since all the CATs interface the same to the radio it is applicable to any CAT. Interfacing to other brands of controllers is similar.

    .There is one interfacing technique that we don't have an article on... it was described to me over dinner a few years ago...
    Take a card like a timeout timer card, strip it, mount an RLC-MOT (and optionally a PL tone decoder) on standoffs, then mount a DB9 or DB15 into the front sheet metal. Slide that interface card into the squelch gate slot. Use the DB connector to connect the repeat audio, COR and PL decode signals to an external controller. The same card can inject repeat audio from the controller into the backplane.
    The controller interface card hadles the repeater in normal use, then if the outside controller takes a dive you can unplug this interface board and plug a regular (unmodified) squelch gate card in to get the system back on the air. Using a squelch gate card does not provide an identifier, but does give you a good emergency kerchunk box (a very basic repeater). The different sounding squelch tail and different carrier delay timer duration will tell your users that the backup "control" system is in place and that they need to voice ID the system.

    .Modifications to the MSR2000 cards by VE6SBS for the VE6NHB repeater     Original article, offsite link
    I suggest you read the entire article first.

    Here are the schematics of his modified MSR2000 card cage and cards: (all are pdf files)
    The modifications on the schematics are not visible - the modified prints look just like original Moto schematics - you will have to compare them to the originals to determine the changes.
          .Backplane wiring   5.1mb
          .TLD9232 exciter   555kb
          .TRD6182 receiver   618kb
          .TRN5069A R1 Audio Squelch   442kb
          .TRN5075A PL encoder decoder   423kb
          .TRN5321A Station Control   343kb
          .TRN5331B Squelch Gate   509kb

    . Documentation on the TLN6721CDX TX Alarm card - (click on the link for photos of the card)
    This card was designed for the Canadian Provincial Police system of over 600 MSRs that was decomissioned about 2002. These were a mix of continuous and intermittent duty 136-150 MHz stations that were deployed in shelters that had battery backup and local AC generators, and an adjacent radio tower, with all of the sites linked by microwave shots. The relay contacts on this card were integrated into the site alarm system. There is a downloadable 4-page PDF containing a theory writeup and schematic linked to this page.

    . Documentation on the QLN2812A Station Identifier Field Modification Kit - provided by John Gilbert KA4JMC
    This kit was made up of a QRN8424B or QRN8425B module, the QKN7547A cable, this documentation and a few other loose pieces.
    The QRN8424B is used in Micor stations, the QRN8425B module is used in MSR2000 stations.
    This module uses a fairly inflexible design - the IDer audio frequency (1,200 Hz) is slaved to the IDer morse code speed. The IDer spacing is either 15 or 30 minutes (but is dependent on the timing of a 555 chip). Both of these modules use a 256x4 PROM chip that is almost pure unobtanium (Monolithic Memories MM5301-1). Each byte represents one time frame, a dit requires two frames, a dah requires four, a word space requires five. Module overhead uses 31 frames. The rest can be used for the actual IDer string (the Morse code sequence). An adapter could be made to allow use of a 27nn or 27nnn series chip, but it's much easier to use an external repeater controller like an NHRC, Scom, etc., but since FCC Rules require you to be able to remotely switch the repeater on and off you need a real repeater controller anyway... and you can buy a decent one for under US$160 (the NHRC-4)

    . Documentation on the TLN640CDX IDer card - provided by www.radiowrench.com       Photo of the card
    No, that's not a typographical error, that part number really has only three digits rather than four.
    If you have an MSR that uses this IDer it's MUCH easier and more flexible to ignore / remove this card and use an external repeater controller like an NHRC, Scom, etc. as this card uses an almost-impossible-to-get 32x8 one-time-burnable PROM chip (yes, 256 bits), plus almost nobody can burn them any more. Yes, you could build a socket adapter and plug in a more modern 27nn or 27nnn series PROM chip, but since FCC Rules require you to be able to remotely switch the repeater on and off you need a real repeater controller anyway... and you can buy a decent one for under US$160 (the NHRC-4)
           Cover page (info on the donor)     Pg1 440kb     Pg2 51.4kb     Pg3 43.4kb     Pg4 93.8kb     Pg5 33kb
           Pg6 55kb (programming chart)     Pg7 40.5kb (parts list)     Pg8 1.32mb (schematic right half)     Pg9 1.25mb (schematic left half)
           Pg10 1.35mb (PCB layout pg1)     Pg11 1.4mb (PCB layout pg2)        All of the pdfs in one zip file for easy downloading

    . A real repeater controller is much more flexible, but if you absolutely have to put a card-based IDer into an MSR shelf you basically have three options:
    1) Mount a mini-repeater-controller like an NHRC-4 or a ICS Basic on a stripped Time Out Timer card and plug it into the Squelch Gate card position, or
    2) Go read the "An IDer for the MICOR Repeater Shelf" article by Jerry Matthews WAĜUZI located on the Micor page at this web site then build it on a stripped down line driver card as shown, or
    3) Purchase an ID-O-Matic kit (for about US$20) from NĜXAS (at http://www.hamgadgets.com), build it, mount it on a stripped-down Time Out Timer card, and patch it into the transmitter audio in the shelf as shown in the Micor IDer article. Like the ID-8 that WAĜUZI used all you need to do to make the ID-O-Matic module work is to hook up power, ground, COR, PTT and audio out, then program it. You may need the buffer amplifier that WAĜUZI used.

    . Documentation of the various jumpers throughout the station - provided by George Henry KA3HSW
    Includes the backplane and the various plug-in boards. Compiled from several MSR2000 manuals.

    . An In-Cabinet Repeater Controller for the MSR2000 station A "Ham Tip" article by Eric Grabowski KH6CQ
    Eric added an NHRC-4 controller to the Squelch Gate board, replaced the card's panel, added four switches, and came up with a nice tight and functional package.



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    This page was created August 1, 2009 by splitting the MSR2000 information off of the Mitrek index page.

    Thanks to Tim Ahrens W5FN for his photos.
    Artistic layout and hand-coded HTML © Copyright 2005 and date of last update by Mike Morris WA6ILQ.

    Motorola® is a registered trademark of Motorola Inc.     Image used with permission.
    Channel Element, Mitrek® and MSR2000® and a bunch more terms are registered trademarks of Motorola Inc.   So there!

    This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.