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Compiled and Edited by Mike Morris WA6ILQ
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Information On and Modifications For Motorola® Test Sets
Compiled and Edited by Mike Morris WA6ILQ |
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The Motorola "Portable Test Set" has gone through several generations. Besides being portable in the sense that a lunch pail is portable, it was never designed to be actually used on portable radios (there were / are specific test sets available for that).
The original test set was the P-8501, and unfortunately I do not have a schematic of it. This unit was built / used in the 1950s and into the mid-60s. They came in factory brown cases, the black one in the lower photo had to have been a field paint job... This test set has/had a crystal oscillator which could be used as a signal source to set receivers on frequency (but there was no easy way to adjust the level of the signal other than detuning the oscillator). The unit used two "D" size flashlight batteries and a 67.5v "B" battery for the plate of the tube oscillator. Some field mods were made to vary the oscillator plate voltage to provide a rough level set, but the oscillator became unstable if the voltage went too low. Other field mods added an atenuator after the oscillator, but most of them had too much RF leakage. Speaking of leaks, the filament and plate circuit btteries leaked, and more than one of these sets are junk due to battery acid eating away the guts. One major design flaw was that the metering cable was wired into the test set, and the point where it met the front panel was a regular failure point from excessive flexing. A common homebrew option was an 11-pin extension cord as on many service calls the test set would be sitting on the floor while plugged into a receiver or transmitter chassis that might be at any height from ankle height to shoulder height. Note the crystals from the era lying on top of the test set in the second picture. I used one of these for years on tube-type mobiles and stations, made my own adapter for Motracs / Motrans from an 11-pin socket and a 13-pin relay that I gutted, and finally gave it all away when I picked up a TU546-series unit that came complete with the 11-pin test cable, the Motrac cable and a Micor cable kit.
The TU546 series:
The "greyface" units were the follow-on models to the P-8501 unit. The TU-series had a front panel connector for the radio cable (finally), but it was a special made by Cinch-Jones corp. The only source of the mate was Motorola at an outrageous price (in 2002 I was charged over $60 for the 20-pin connector (part number 09-00855269), shell and cable clamp).
NOTE: Think SEVERAL times before taking the test set cable connector apart! It falls apart into a bunch of pieces and is a major pain in the rear to put back together !
How to ruin your test set: Both the TU-546 series and the later S1056 / 1057 / 1058 / 1059 test sets were powered by four 1.5v "D" cells in series plus one 1.9v mercury "N" cell - and the "N" cell is buried inside and EVERYBODY forgets about it (there is a photo linked down further on this page in the S1056 section that shows you where it is). The "N" cell is only used in receiver metering position 4, and Moto slipped up in the initial design by not having a "Transit" or "Off" position on the rotary switch, or at least adding a note on the front panel to the effect of not leaving the switch in position 4 when not in use. I have seen more test sets ruined by leaky "N" cells than I want to think about. The "power switch" for the four "D" cells is implemented as a jumper in the 20-pin metering cable connector, so by simply removing the cable turns off the 6v battery. In addition to the "D" and "N" cells the deviation meter option had its own internal power supply (a pair of 6.5v mercury batteries).
So add a label to the unit saying something to the effect of:
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DO NOT leave the main metering switch in Position 4 !!! |
The greyface test set cabinet was designed for up to two options to be added - your choice of an audio generator, a peaking generator (equivalent to the crystal oscillator in the P-8501) and a deviation meter. The dev meter option depended on the peaking benerator being there already. The owner of the test set in the upper photo used the option space to store metering cables and a microphone. The test set in the lower photo has the peaking generator option installed, and the Micor test cable plugged in. The peaking generator has a multiposition switch (the leftmost one in the photo) to select any one of several internally installed crystals or the front panel sockets (three different sizes, all in parallel).
Test Cable Numbers:
The above photo shows the three most common cable kits...
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Not shown is the common homebrew 5 to 6 foot long 11-pin extension cord. It is made up of the raw bulk test set cable (part number 30-82020H01), plus a set of 11-pin connectors which are no longer available from Moto, but are available from Heath and Collins enthusiasts, or on eBay. |
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The SKN6013 cable is the original tube type radio cable - it has the 20-pin test set plug (painted blue in the photo above) on one end and the male 11-pin octal style plug on the other. The documentation on it is in the test set manual. In the photo above it starts at the blue plug and ends at the 11-pin octal style male that has the chrome plated pull rod attached. |
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The TKN6025 cable is the adapter cable for the above cable. It has the female 11-pin octal style plug on one end and the 12-pin miniature plug (for Motrac / Motran / Mocom / Mitrek radios) on the other. In the photo above it starts at the 11-pin female octal style socket and ends at the aluminum cylindrial plug. The "manual" on the TKN6025A is a single page schematic and parts list 68P862697-E. Scan courtesy of Tom Gunderson W9SRV. |
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The SKN6012 cable has the 20-pin test set plug on one end and the 12-pin miniature plug on the other - it replaces the combination of the above two cables. In mid-2006 the price on this cable was about $130. The "manual" on this cable is 68P81120A22-B. |
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The TEK37 series cable kit allows the test set to be used on Micor radios. It is
made up of one plug assembly that plugs into the test set plus two TEKA-72 cables. Heres a photo of a fresh-out-of-the-box
TEK-37A, and the lower of the two TU-series photos above shows it plugged
into the test set. The TU-series and the early
S1056 / 1057 / 1058 / 1059 series test sets
must be modified to work with the Micor kit (the mod simply adds Micor functionality
without removing any). The documentation on the TEK37A Micor cable kit is
68-81121A01 at about $2 (in 2006). The cables used in this kit had their own part
number (TEKA-72A)and their own "manual", the 68P84258C53-A. In the cables photo above it's at the top, and
is also visible plugged into the lower TU-series test set. The original TEK-37 had a
two position switch that controlled the voltmeter sensitivity, the later TEK37A dropped the
switch. Here's a schematic of the TEK-37 showing both
versions. You can add a SPDT switch and an 18k resistor to a TEK-37A to get the TEK-37 functionality if you want to. If you have an old cable (perhaps the 11-pin tube-type radio cable) and you want to convert it to a Motrac / mocom-70 / Mitrek end the parts kit for the complete kit for new end is 1V-80754A26. The more modern number is 0180754A26 and it will set you back about US$17 to $18. Here's a photo of the kit, courtesy of Eric Lemmon WB6FLY:  |
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The TEK19 is a square plug adapter that plugs into the test cable connector and tests any of the round-plug microphones from the Motrac/Motran/Mocom series. Here's a photo of a TEK19. Simply plug the TEK19 into the test set, plug a microphone into the connector, squeeze the PTT and talk into the microphone. If the meter peaks at over some magic value, the microphone is good. Unfortunately I don't have any literature on the TEK19 so I have no idea what the magic number is... Various adapters / adapter cables allow testing microphones that have other connectors (Micor/Syntor/Mitrek/Maxtrac/Spectra/etc). Does anybody have a copy of the Moto info sheet on the TEK19 ? We'd like to scan it. We'd also like photos of the microphone plug adapters. |
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The TEKA-57 looks like a TEK-19 but with a slide switch on top, and a thin (computer mouse cable diameter) cable coming out the side. Here's a photo of a TEKA57. The cable is terminated with a 1/8 inch diameter mono plug, and was used to measure the audio output from a handheld for 20db quieting checks. The TEK17B was a similar unit but with two slide switches on the top. Does anybody have a copy of the Moto info sheet on the TEK-17B or the TEKA-57 ? We'd like to scan it. We'd also like a better photo. |
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The TEKA-74 adapts a Micor microphone to a round-plug (i.e. Motrac/Motran/Mocom) environment such as a TEK-19, TU546 or S1056. A microphone test only uses three wires (PTT, ground and audio) so building an adapter for other Moto microphones is easy. Does anybody have a copy of the Moto info sheet on the TEKA-74 ? We'd like to scan it. We'd also like a photo. |
Here's the Moto portable test set schematic:
Horizontal format (for viewing)
137kb Vertical
format (for printing) 168kb
The S1056 / 1057 / 1058 / 1059 series:
The "silverface" test sets were the follow-on models to the TU-546 units. They are pretty much just a cosmetic update and as such all of the TU-series test cables will work on the S-series test sets. The major electrical difference is that test sets manufactured after 31-December-1969 left the factory with the Micor mod already installed.
The silverface test set also has the "forgotten N-cell" problem mentioned above, so make sure you add the warning label mentioned in the greyface section above.
By the way, the real S1056 / 1057 / 1058 / 1059 test set manual is part number 68-81011A01 at around $5 (2005 prices), however last I heard they were out of them and not planning to reprint them. But if you are calling Moto parts for something else it doesn't hurt to ask...
More S1056 info:
The schematic: Schematic Left Side Schematic Right Side
The extreme left side shows the schematic of the 11-pin octal-style and Motrac/Motran/Mitrek cable and of the Micor cable.
A diagram of what switch does what....
A scan of the chart that goes inside the cover If yours is missing you will want to print this, then have it laminated
A scan of a page from the manual showing just where the infamous "N" cell is located Look for the words "ZERO CENTER BATTERY" on the left side, then follow the arrow.
The above files were from WA6ILQs file cabinet.
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The R-1033 / RTL-4118 / RTL-4119 Test Set Series This was a follow-on to the S1056 / 1057 / 1058 / 1059 series. Besides being a complete ground-up redesign, it has several nice features including a built-in SINAD meter (this test set was the first Moto set to have a SINAD quieting measurement as well as a 20db measurement). It also has enough room in the lid to store several cables (if you had both option slots in a TU-series or an S-series test filled you had room for only one cable in the lid...), a built-in audio generator, and it uses common DB37 cable connectors. Another feature is that the PTT switch has the option of sending a dead carrier or one modulated with an audio tone. Power is supplied by a single common 9v battery (do yourself a favor and put a label on the front panel, perhaps above the meter, with a note as to when the battery was last replaced, then change it every year, no matter if it needs it or not). There is no battery on/off switch - like the TU-series greyface and S-series silverface sets the battery is disconnected when the metering cable is unplugged. The basic portable test set is the R1033, two variants on it were designed to fit into the lid of the service monitors of the day, the RTL-4118 for the R2001, and the RTL-4119 for the R2200 monitor and are simply repackaged versions with no schematic changes. Here's manual 68P81069A78 for the R-1033. The manual PDF was donated by Eric Lemmon WB6FLY. Unfortunately the manual does not contain any test cable schematics.   The front panel above has two microphone connectors - the round plug for the Motrac/Motran/Mocom style microphones and the black square to the right of that is an RJ45 jack for a Maxtrac style microphone. The TEKA-74 adapter mentioned above converts a Micor microphone to the Motrac style connector. Another adapter is used on the Spectra style plugs (does anyone have the part number? Or a photo and a writeup we can scan?).
Cable Numbers: (if anyone has cable schematics or other paperwork please let repeater-builder know).
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Manual 68P80309B90 for the RTX4005B Portable Radio Test Set This is a specialty device for testing MT500, MX300, HT90, HT440, HT600, MT1000, PT500, MX series, Expo, Saber and Astro Saber handheld radios. Manual PDF file donated by Eric Lemmon WB6FLY. A cable from the RTX connected to the speaker-microphone jack and allowed tapping the microphone line for injecting audio (like from a signal generator) or tapping receive audio (for making quieting measurements while aligning the radio). The "A" and "B" vintages of the RTX set are different, and the RPX4665A mod kit will field update the "A" series units to the B revision. Here's a photo of the RTX4005A unit - note that under the blue "Motorola" logo the front panel says "MT / MX Test Set". There is a label on the bottom that identifies it as a RTX4005A.  Moto made an upgrade kit for the A-version units under the part number of RPX-4665A. The right side photo shows an upgraded "A" version test set. The kit is not cheap, in December of 2006 it was about US$105. It would probably cost less to buy a "B" version test set on eBay. 
 Here's a photo of the later RTX4005B. Note the front panel identity (just above the speaker). The major electrical change is the switch under the right edge of the speaker.  The cables made for this series test set could also be used without it as a radio programming cable - the connector that plugged into the test set had a protective rubber cap (usually green) and that pigtail could simply be ignored. The RTK4203C cable is used to talk to the Saber handhelds, the RKN4046A is used on the Astro Saber. Here's a photo of the RTK4205C cable that is for the P210, HT600, MT1000, P500,HT800, MTX800, MTX900 and MTX Classic. The other end of the black box with the "CVC / NORM" switch is a female DB25 connector that plugs into the RIB for programming the radio. The switch is used to change the mode of the radio from normal to thinking that it is inserted into a Convert-A-Com or MVA mobile adapter/charger. 
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The bench-top test equipment line included "test sets" designed for specific purposes. There was a two-tone sequential encoder made to plug into an RF generator to test pagers, and there was the SLN6413 DPL test set shown below:
The two black rectanges (with the pin inserts) that are on each side of the
thumbwheel switch are designed for testing encode and decode plugs like the
TRN6005 (which has a how-to-make-your-own construction article at this web
site). Like most Moto-designed bench test equipment the SLN6413 can run off
of 120vAC or +12vDC. There is a power mode selector switch and a DC input on the rear.
Moto also made test sets for stations (i.e. base stations and repeaters). Here's a scan of the schematic of an older tube-type base station metering kit - the ones with the 11-pin octal-style connectors (scan courtesy of Bob Meister WA1MIK):
Versions of that unit were an option in the "Deluxe Line" and "Research Line" base stations of that day, here are two photos of a late 1950s / early 1960s tabletop base:
A later series, the Motrac / Motran / Mocom-70 series stations had a similar metering kit. Two versions were made, one designed for cabinet racks where the meter is mounted in a meter / speaker panel in the top of the rack (above the door). This panel was more of a swiching panel as it did not have a physical meter. The second version was designed with a meter for the outdoor / weatherproof rack cabinet... On both test sets one connector pluged into the receiver chassis and the other into the transmitter chassis. The leftmost slide switch in the photo reversed the meter connections (on most Moto test sets one receiver metering point is a "tune for zero" function), the other switch selected either the speaker or a ten ohm resistor...
Here's a TLN1552A metering-only panel from an early Micor outdoor station:
Here's the TLN1867A/TLN5900A metering and intercom panel from the later Micor station. If you look closely at the bottom right of the top picture you can see both numbers stamped on the bottom of it. The middle picture shows the numbers - and why it has two numbers is beyond me. The screws visible at the bottom left and bottom right go into predrilled and tapped holes in the face of the station. The "fuse clips" are designed to hold the red and black test probes as shown in the lowest photo. The TMN6071A is the microphone that was shipped with this unit, but any Motrac/Motran/Mocom70 microphone will work just fine.
There were also metering kits made for the tabletop base stations. Except for the color of the plastic panel behind the switch, they were almost identical between the Motrac, Motran, Mocom-70 and Mitrek stations. Here's the manual for the Mitrek version, the HLN4138A, courtesy of Eric Lemmon WB6FLY.
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Credits:
Tube-type base station metering kit schematic was scanned by Bob WA1MIK from the 1960s book titled "FM Schematic Digest - A Collection of Motorola Schematics, Published by: Sherman M. Wolf - Boston, Massachusetts" - commonly called "The Red Book".
Other contributions from Skip Hansen WB6YMH, Jim Scott N8ORJ, Will Martin KA6LSD, Doug Marston WB6JCD, Jeff Kincaid W6JK, Neil McKie WA6KLA and others.
This page was created on 04-Apr-2007 by taking all the test set information from the main Moto index page and splitting it off onto this page.
Artistic layout, several of the photos and the hand-coded HTML is © Copyright 2007 and date of last update by Repeater-Builder.
Motorola® is a registered trademark of Motorola Inc. Logo image used with permission.
Registered trademarks, service marks, or copyrights of Motorola Inc. include all of the the model names ("Deluxe Line", "Research Line", Motrac, Motran, Micor, etc.) mentioned above, and a lot more that I can't remember at 2am as I'm creating this page. In short, trademarked / service-marked names belong to the owner and no misuse, violation or infringement is intended.
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.
