Until one turns up, here's the schematic, and here's the board layout.
This is a 144-148MHz 30w FM out, 1/2 to 5w in FM only amplifier
This is a 28.0-29.7MHz 25w SSB & FM, 7w AM unit
A note from the donor:
Attached are the HTX-10 schematics and manuals. The HTX-10 PDF manual with schematics from the Radio Shack service manual is pretty poor. BUT ! The Albrecht AE485s and AE485s_25W schematics are VERY similar to the HTX-10 schematic and can be used (along with what's in the HTX-10 book) to more easily figure out what you need to do to work on your HTX-10.
AE485s schematic AE485s_25W schematics
HTX-200 2M Radio Parts List
The 202 is the 2 meter HT and the 404 is the 440mhz HT that were made by Maxon for Radio Shack and loosely based on the Icom IC-02 and 04 design. Since Radio Shack as abandoned their customers does anyone know of anyone that services them ? I'll be happy to put a pointer here.
This well written article explains why the HTX202 and HTX404 have DTMF control problems... why you can't run both subaudible tone encode and DTMF at the same time.
This is a local (at www.repeater-builder.com) copy of the web page at the VE6SBS web site only because that site was down several times after I referred folks to it. I decided to put a local copy here at repeater-builder just in case Barry's web site went away completely.
Out of the box this radio covers only 440-450MHz. A few keystrokes opens it up to 430-450MHz. As easy as it is to do, why not? The extra coverage can be useful sometimes, for example in 2m transmitter hunts (146.565 is the hidden transmitter frequency in many areas, and 439.695 is the third harmonic. By listening there I can walk up to within a few feet of the fox.)
NOTE: This zip file contains 70 seperate files, one file per page side, and two files per half-schematic. If anybody has a paper copy we can borrow we can get that scanned into a proper PDF file with wide-page images for the pull-out schematic pages that would be good.
Here's the above 70 files as one 23 MB PDF...
This manual is for the Albrecht AE-540 which is very close to the HTX-252. Interestingly enough, the photos are of a unit with the "Radio Shack" name on it.
The Pro-43 scanner (model number 200-0300) was introduced in 1992 and for a long time was their only portable scanner where the "UHF" band was 200-512 Mhz instead of 400-512 Mhz (they marketed the addition as adding military aircraft coverage), and "low band" was 30-54 Mhz instead of 30-50 Mhz. Yes, not only did it cover 6 meters but it also covers amateur 220-225 Mhz right out of the box. And it doesn't need a special battery pack - you can use either penlight nicads or penlight alkaline batteries. And if you do put rechargeables in it, you will find a charger jack already installed in the side of the unit waiting for you! It was made by GRE for RS, and was before the days of CTCSS or DCS, alpha tags and trunking. This unit was the first portable triple conversion scanner from RS and the first to come with AM mode selectable on bands other than the aircraft band.
By the way, the Motorola GP-300 handheld balistic nylon radio case is an absolutely perfect fit (anybody have the Moto part number? I'll add it here).
The Pro-2002 scanner (20-116) was one of the first decent programmable scanners. It uses the so-called "Motorola" antenna jack for the external antenna and the adapters are a little hard to find (RS does offer a motorola-to-female-BNC adapter, part number 278-208, and your store can get it if they don't normally stock it). Some folks have ended up ignoring the stock antenna jack and adding a BNC next to it, or removing it outright and using the hole for a replacement BNC jack. The screw-in rod antenna uses a metric thread and as a replacement part is pure unobtanium in the USA. The 2002 handles 50 channels in low band (30-50 MHz), high band (138-174 MHz), aircraft (108-136 MHz) and UHF (410-512 MHz). As a scanner, it's nothing special, except that they are usually found in the $1-$25 price range, have a large, clear speaker, and the book is impossible to find, except here. If your local public service agencies run conventional (as opposed to trunked or P25 digital modulation), it's a good-sounding inexpensive programmable unit to park on some local channels.
The PRO-2003 was the predecessor to the 2004-2005-2006 series of scanners and in late 1985-early 1986 was the top of the line and the price reflected that (and as a result it didn't sell very well), plus it scanned at a rate of only 8 channels per second where the competition did 15 to 16 per second. It offered 50 memory channels and covered low band (30-50MHz or 66-88MHz, depending on the country), 108-136 MHz AM Aircraft, 138-174 MHz (various), the 2m Amateur and high band, 148-174 commercial and public safety, 410-512 MHz (410-420 Government band, 440Mhz amateur band plus connercial), plus (and this was unusual) the FM broadcast band. The packaging was almost identical to the future PRO-2004, but the keyboard labeling was poor.
The 2004-2005-2006 series of scanners was the top-of-the line of the conventional-only scanners and were built for RS by GRE of Japan. Introduced in mid-late-1986. They covered 25-520MHz continuous (10m, 6m, Aircraft, 2m, 220, 440Mhz amateur bands), 760-824MHz (800mhz repeater inputs), 851-869Mhz (repeater outputs), and 896-1300Mhz (900mhz and 1.2ghz amateur bands) in AM, NBFM and WBFM. Has 300 channels in 10 banks of 30, backed up by conventional 9 volt alkaline battery. Any channel can be designated the priority channel. "Sound Squelch" allows skipping dead carriers during search or scan. There is a tape recorder output jack on the back which provides 600 mV of audio at about 10,000 ohms impedance. There is a design oversight in all three models - the audio level of AM signals is somewhat below that of NBFM signals, requiring a different setting of the volume control. When scanning both AM and NBFM modes, one has to find a compromise position of the volume control. A trimpot or two in the audio mixer that combines the outputs of both detectors can be added, but a bit more care in the initial design would have precluded that necessity. One popular mod makes the unit portable by removing the power transformer and replacing it with a 12v gell-cell. You can charge it with a 12vDC wall-wart transformer (plugged into the existing +12vDC input jack).
There are some cosmetic differences like the keyboard layout, but the internal electronics design is very similar across the three receivers. The major differences were physical packaging and the position of a few diodes in the configuration matrix plus:
| The 2004: |
The 2004 (model 200-0119) was introduced in late 1986 and nearly 45,000 were sold until until it was discontinued in early 1988. It had a metal case, good internal construction and shielding, but no way to add a mobile mounting bracket and while teh DC power jack was there RS didn't offer a DC power cord. It was artifically limited in the number of channels it could listen to and had a slower scanning speed. You could cut a diode and get the 400 channels of the 2005 but the channel numbering on the 300-channel keyboard (which was not backlit) would be confusing. Another diode cut got the faster scanning speed of the 2006. Adding either a COS or a TS32 PL decoder (or both) was easy - in fact a Pro-2004 was my across-the-garage link receiver or remote base receiver for repeater experimentation for several years. You can improve the squelch action by replacing R148, a 47K resistor, with a 220K value.
See "Product Review: The Radio Shack PRO-2004 Programmable Scanner," by Bob Parnass AJ9S, in Monitoring Times, March 1987. Anyone have a scan? One common problem with the PRO-2004 involves the memory backup battery circuit. The 9v Alkaline is the only thing keepng the memory alive. Sometimes the low battery warning keeps activating even when a fresh battery is installed. Memory loss when the radio is unplugged is also a symptom of the same problem. Make sure the contacts on the battery connector are tight. The snaps widen and lose contact, and you can squeeze them gently with a pliers to tighten them. Unplug the AC cord from power and remove the battery. After a few minutes, insert a good battery, plug the power cord back in the wall and perform a full reset according to the owners (instruction) manual. Check the through-board solder joint at connector CN6, pin 3. Check the wires from the battery connector to the printed circuit board for continuity. If a new battery goes dead after just a few days, it is likely that the memory regulator has gone bad. The regulator is in a TO-92 package and looks like a small transistor with three leads. It is labeled IC9 on the printed circuit board. The part is made by Seiko, type S81250HG. Type NJU7201L50, available from Mouser Electronics, may be used as a substitute. The PRO-2004 had serious quality problems with its printed circuit boards, especially during the 1987 production year. There are copper traces on the top and bottom of the boards. In places where it is necessary to connect top and bottom traces together, a hole was drilled and then plated with copper to make the connection. This plating was faulty and over time it cracks, breaking connection from top to bottom. The symptoms can range from corrupted memory to the squelch not working. Sometimes the problem comes and goes or may be sensitive to temperature. The only way to permanently fix the problem is to put wires in all the holes and solder the connections on top and bottom. Pop the tops off the shields and repair the connections inside too. This takes a huge amount of time and many repair shops consider the PRO-2004 to be unrepairable. When the unit was in warranty Radio Shack just swapped the boards, then crushed the old ones. Another problem involves the glue GRE used to secure the large power supply capacitors to the main PC board. It's often black in color and you should see it around the base of the capacitors. There is a corrosive element in the glue and given enough time it eats through the copper on the PC board. The glue can be scraped off the board with a toothpick (don't use a metal tool) and you can then assess the amount of damage due to corrosion. Repair any broken traces with small lengths of wire soldered down to bridge the gaps. |
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Pro-2004 Operation Manual 1.48 MB PDF donated by A. Nony Mous |
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Pro-2004 Operation A text web page from the RS fax-back system that covers the basic operation. |
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Pro-2004 Service Manual 38.8 Mb PDF |
| The 2005: | The 2005 (model 200-0144) was introduced in 1989 and was essentially a 400 channel size-reduced Pro-2004 packaged in a smaller plastic cabinet (which reduced the shielding). The size reduction was accomplished by converting from through-hole to surface mount circuit boards. The unit had a better keyboard (but it was not backlit) however the layout was easier to use when mobile. The 2005 was a bit more sensitive than the 2004 but had a problem where 800 MHz signals leaked into the aircraft band. You could cut a diode and get the faster scanning speed of the 2006. |
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Anybody have a PDF of the Pro-2005 Owners or Service Manual?? |
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Pro-2005 Operation A text web page that covers the basic operation. |
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Pro-2005 Parts List 22kb
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| The 2006: |
The 2006 (model 200-0145) was introduced in 1990 and was essentially a faster scanning PRO-2005. It's probably the best conventional-only scanner made to date. You can improve the squelch action by replacing R152, a 33K resistor, with a 100K. See "The Realistic PRO-2006," by Bob Parnass, AJ9S, in Monitoring Times, October 1990. Anyone have a scan? |
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Pro-2006 Owners Manual 1.03 Mb PDF (20-145) |
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Pro-2006 Exploded View 19kb |
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Pro-2006 Parts List 22kb |
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Pro-2006 Service Manual 5.2 Mb PDF |
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Pro-2006 Service Manual Addendum 512 Kb PDF |
| #19-345 Simplex Repeater Controller Note that this box is incorrectly called the "Simplexor" by some folks - that name is trademarked by Zetron and used on their Model 19B (and information on that unit is on the Zetron page at this web site). |
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Anybody have the Service Manual in PDF ? |
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Users Guide 162 Kb PDF |
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Operation. |
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Features. |
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Hints and Tips. |
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Specifications. |
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Power options. |
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Parts list. |
Test Equipment |
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22-305 LCD Frequency Counter Owners Manual 238 KB PDF donated by John Anderson WD8RTH This is a two-range hand-held frequency counter that is good from 1Mhz to 1Ghz, packaged in a VERY sturdy metal case with minimal controls: a power switch, a Hi-Z/50 ohms sqitch, a range switch, and a gate speed selector and a LCD backlight pushbutton. It's a lot better built than the average pice of RS equipment. 22-305 Frequency Counter Operation donated by "Sal C" - appears to be a faxback page that is no longer on the server. Additional info: Features Parts List Power Source Specifications |
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Model 277-1008 Mini Audio Amplifier schematic 71 KB GIF. Thomas Myers N9LHK sent me a very good, well-lit closeup photograph of the schematic sticker that was in the early units (they no longer do that). I played with and
cleaned up the image a little using a couple of graphic programs. This is a single LM386-based unit that is VERY handy when debugging repeater controller problems. Just note that the unit has an input impedance of 5K Ohms, and may load down a high impedance source. If the 9v battery seems to die 'way too soon check for excessive leakage in the 47uf 10v electrolytic cap that goes from pin 6 to pin 4 on the LM386 chip. The cap in my unit was leaking 19 ma worth... a new cap fixed it (the LM386 chip is spec'd for less than 5ma at idle). Here's the mod to add a normal / de-emphasis switch. The de-emphasis curve is dependent on the RC values - do not subsitute. Adding the switch and the parts allows you to monitor receiver discriminator ("flat audio") sources. Here's the LM386 data sheet at the National Semiconductor web site. If you are going to build your own version of this unit a better choice is the LM4951 (and it has an optional mute/PTT input as well). You can build one into an old Motorola mobile speaker housing, and put the volume control and power switch into the side or back wall. |
Accessories and Other Products |
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Radio Shack "Amplified Mobile Extension Speaker" (model 21-541) - Schematic
Parts
List. This unit is a cheap knockoff of Motorola's "Power Voice" mobile speaker with an interesting design twist. It's designed for the situation where the speaker amplifier in a CB doesn't have enough power to be heard, for example in a pickup truck with the windows open. Obviously it's just as usable on ham radio as on CB. The interesting twist is that the DC power to the audio amplifier is controlled by a VOX-type of circuit. Motorola's design didn't need it. |
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20-2006 telescoping antenna 35 KB PDF |
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21-1384 External Speaker-Microphone 6.3 KB PDF (anyone have the schematic ?) |
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21-1898 Headset 432 KB PDF A nice unit, but no schematic is provided. |
Weather Radios (or as Radio Shack calls them, WeatheRadios) |
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Weather Radios, no matter who makes them, have two purposes. First, they are a receiver preset to the NOAA Weather Radio (NWR) services frequencies, and they receive regular, around-the-clock weather status and forecasts information. Second, the newer ones are designed to respond alert signals sent by the NOAA Weather Radio service. When the weather radio receives an alert signal, it will respond with an audible alarm to attract attention. The Weather Receivers come in three flavors: the plain monitor receivers that listen to the weather channels and has no warning mechanism at all (same functionality as having the local weather channel in your handheld), secondly the simple first generation alert receivers that decode the 1050hz alert tone, and lastly the second generation receivers that use a type of digital coding called Specific Area Message Encoding or SAME. The SAME system divides the United States into geographical weather areas and you program the reciever to respond to the geographic code (called a FIPS code) for your local area (or if you live near a boundary, you program in both codes), or if you want, you can add the codes for the areas surrounding the perimeter of your FIPS area. Most of the codes are aligned along county lines, but as we all know RF doesn't pay attention to political boundaries. The first weather channel allocated was 162.550 MHz, then 162.40 was addded and 162.475 shortly after that. Most second hand receivers that you find will be single channel (162.55), rarely two channel (162.550 and 162.40 MHz) and usually either three channel (162.550, 162.40 and 162.475 MHz), or seven channels. There is a lot more information on weather radios and the SAME system on this page. |
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If anyone has info on other RS receivers, please send it in. |
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There is an article on interfacing a Reecom brand weather receiver on the Arcom page at this web site. The Reecom is a decent knockoff of the very desirable Radio Shack 12-250. |
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#12-140 "Weatheradio Alert III" – This is an older three channel receiver. It is powered by a normal power cord and has a 9v battery pocket in the bottom of the case. |
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#12-152A – This is another three channel synthesized receiver, despite the fact that it is labeled as "Crystal Controlled Weatheradio". It uses one 9 volt battery or an external 9v wall wart transformer. |
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#12-154 – This is also a three channel radio with a 1050 Hz tone decoder. |
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#12-240 "Weatheradio with Alert" Owners Manual 139kb PDF This unit is also a three channel unit, and decodes the 1050 Hz alert tone. It is powered by 120vAC. |
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#12-241 "Desktop Weatheradio" Features, Power Sources, Operation, Specifications Manual 16kb PDF This is a 3-channel receiver. |
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#12-247B "Weatheradio Alert" This is a 7-channel SAME receiver, with the NOAA logo, powered by an AC cord but with a 9v battery compartment. The external antenna connector on the rear is an RCA jack. We don't have a PDF of the owners manual, does anybody? |
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#12-248 "7 Channel Digital Pocket Weatheradio Alert Manual" 480kb PDF This unit receives all seven NOAA channels and decodes the 1050 Hz. alert tone. |
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#12-249 SAME Weather Receiver Owners Manual 684kb PDF Note that to receive multiple geographic areas (up to 15) you have to set the single/multiple switch on the bottom of the unit to the multiple position, otherwise it monitors position one no matter how many are programmed. Some of these radios have firmware that does not recognize the EOM signal. These have a fixed 5 minute message timeout. This unit has an external antenna jack, plus a 2-pin terminal strip (accessible from outside the case) for an external alarm. These terminals on the radio have a constant 1.2 VDC on them until an alert is received, at which point the voltage goes to 7.2 VDC, and remains there for the length of the alert, or until the alert is manually turned off. The 7.2 VDC only appears when an alert is sent by the National Weather Radio service and does not appear when conducting a self-test of the radio. The voltage is at a low current (originally designed to feed an X-10 Encoder, but very useful for other things). Don't plan on powering anything more energy intensive than a Solid State Relay, a switching transistor, or maybe the coil of a reed relay. Here's what the terminal strip was designed for. Here is the RS #12-249 Support Page. |
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#12-250 SAME Weather Receiver Owners Manual 466kb PDF A stock photo of a 12-250 An updated version of the above receiver that supports a wider variety of alert codes and has the two pin terminal strip (see the 12-249 above for information on the terminal strip). If you are going to use an RS Weather receiver this is the one to look for (the 12-249 is your second choice). Here is the RS #12-250 Support Page. |
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#12-251 SAME Weather Receiver Owners Manual 949kb PDF A cost reduced unit that cut the geographical areas to two, and deleted the external alarm terminal strip. Here is the RS #12-251 Support Page. |
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#12-255 SAME Weather Receiver We have no information on this unit (yet) except what RS has on their #12-255 Support Page. The owners manual link is broken there, it points to the 12-251 owners manual file. |
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#12-257 SAME Weather Receiver We have no information on this unit (yet) other than the #12-257 SAME Weather Receiver Owners Manual 118kb PDF This is a pocket unit not much larger than an FRS radio, with a cute feature: it has a vibrator mode (like a pager or cellphone) that can be set to trigger during warnings or alerts. |
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#12-260 SAME Weather Receiver and alarm clock - As of April 2009 this is a current product, and is sold as a bedside radio/alarm clock. We have no technical data on this other than the advertisement on the RS web site says it has a scan function in case the local weather transmitter goes off the air. The photo shows only one LED indicator. The RS web site does not have a #12-260 Support Page, but courtesy of Robert Stiles we have a PDF of the owners manual: high resolution (2.8 MB) and a slightly lower resolution (530 KB). Other than a page of specifications there is no tech info in the owners manual. |
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#12-261 SAME Weather Receiver 2003 vintage Owners Manual 2004 vintage Owners Manual This unit has a 9v battery pocket in the bottom of the case, or can use an external 9v wall wart transformer (the book says the battery is for backup purposes). It also has an external antenna jack, plus a 2-pin terminal strip accessible from outside the case (like the 12-249) for an external alarm. Here's what the terminal strip was designed for. There is an interfacing article below on this unit. The RadioShack 12-261 Desktop SAME Weather Radio Support Page A stock photo of a 12-261 |
| Weather Receiver Interfacing Articles | ||
| These articles cover only the interfacing aspects. At some sites the Weather Radio may suffer from RF overload, which may require other methods to resolve, up to and including repackaging the Weather Radio receiver in a shielded box and feeding it with an outside antenna. Extreme situations may require a cavity filter between the antenna and the receiver-in-a-box. | ||
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Interfacing the Weather Radio to a repeater controller Scott Zimmerman N3XCC connected a #12-251 Weather Radio to an Arcom repeater controller, but the 12-249, 12-250 and similar receivers (like the Reecom) would work just as well. This article describes the hardware interface only. The outputs for Statement, Watch, Warning and COS connect to alarm inputs on the RC210, and the receiver reset input is connected to a digital output (and is used to acknowledge or clear the Statement, Watch and Warning alerts). See the "More than three ports?" article on the Arcom page at this site for a method of interfacing a Weather Radio without using one of the three ports on a RC-210 or one of the 8 ports on an RC-810. |
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Another take on interfacing a Weather Radio to a repeater controller Kevin Thomas W6KGT (ex-KB5ZVK) uses two opto-isolators and two relays to connected any Weather Radio to a CAT-1000 repeater controller. The design is generic and can be used on any brand of repeater controller. A digital output on the controller programmed for pulse mode could drive a reed relay whose contacts are wired across the reset button in the weather receiver. |
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A third take on interfacing the Weather Radio to a repeater controller Fred Vobbe W8HDU connected a #12-249 Weather Radio to a Link brand repeater controller. This article gives an overview, a list of links to geographic zones, a codes table, describes the hardware interface he built, and covers the Link RLC-series controller programming in detail. The 12-250 and 12-251 and similar Midland receivers would interface very similarly. This is a local copy (at repeater-builder) of Fred's original article, which was at http://vobbe.net/hamradio/wxrad/index.html but it's gone now. |
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Yet another take on interfacing a Weather Radio to a repeater controller KF4PXZ connected a #12-250 to an Arcom RC-210 repeater controller. This short article shows where to pick up the decode alert logic line and the audio. The 12-249 and 12-251 would interface very similarly. |
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An Automated Repeater SAME Weather Alert by Stewart Radinowitz KE5UT This writeup uses a 12-261 WeatheRadio. A stock photo of a 12-261 This writeup describes how to use an inxpensive VOX unit to generate the Alert or Warning signal for the COR lead of the radio port on the repeater controller. The technique could be used on any receiver (RS or otherwise), just remember that the properly designed SAME radios (i.e. one that uses the audio "turn off" code) will forward the entire alert (no matter how long), whereas the Midlands use a shutoff timer. The RadioShack 12-261 Desktop SAME Weather Radio Support Page is here. |
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This page initially created 14-Oct-2004.
Radio Shack, Realistic, Archer and probably others are legal trademarks / service marks of Tandy Corp and no infringement is intended. The amateur radio equipment manual PDFs are here due to the interest expressed in the Tandy-Radio Shack-made equipment by the amateur radio community and the fact that they are no longer available on the public RS web site. The scanner manuals are here because most are not available from anywhere else and in any form.
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.