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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. 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. Note the crystals from the era lying on top of the test set in the second picture. Some field mods were developed 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 mod was to put a socket into the panel and a matching plug on the cable (see the photo below of a modified test set). One common problem was that on many service calls the receiver or transmitter chassis that might be under test was at any height from ankle height to shoulder height, so common homebrew option was an 11-pin extension cord since the test set would be sitting on the floor. Another common homebrew option was a steel rod hook that hung the test set from the top of the cabinet door. 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, cut one pin off and wired a cable into, and finally gave it all away after I picked up a TU546-series unit that came complete with the 11-pin test cable, a real Motrac / Motran 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 (part number 09-00855269) 20-pin connector, shell and cable clamp kit).
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 (I also saw one where the owner relocated the zero center adjustment pot to the front panel, took a piece of dowel the size of the "N" cell, pushed two brass thumbtacks into the ends as contacts, soldered a piece of zip cord to the thumbtacks, put the dowel into the battery holder, and fastened a &qyot;C" battery holder in the cable storage area to hold the replacement for the "N" cell). The "power switch" for the four "D" cells is implemented as a jumper in the 20-pin metering cable connector (pin 19 to pin 20), so by simply removing the cable turns off the 6v battery. In addition to the four "D" cells and the "N" cell 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 affecting anything else). 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 (TEKA72A)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 TEK37 had a two position switch that controlled the voltmeter sensitivity, the later TEK37A dropped the switch. Here's a schematic of the TEK37 showing both versions. You can add a SPDT switch and an 18k resistor to a TEK37A to get the TEK37 functionality if you want to. |
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An early version of the TEK37 was the 01P84253C65 adapter. If anyone has a copy of the writeup we can scan please let us know. |
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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 and literature of the other microphone plug adapters. |
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The TEKA57 looks like a TEK19 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 R1033 / RTL4118 / RTL4119 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. 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. It's apparent that Moto learned three lessons from the older greyface/silverface sets, the first is evident in that this design has a meter position to read the voltage of the internal battery, the second is that there is only the one battery, and it is a single common 9v battery, and the third is that the battery is easy to change. Still, 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. If the test set is going into storage for a while, remove the battery. The internal speaker leaves a lot to be desired, more than one test set has been modified with an external speaker jack. 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 black rectangle to the right of that is the common DB-37 connector for the radio cable. 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?). CAUTION: The R1033 has an internally grounded speaker. When used with the RTK4043A cable to meter the test points in a MSR2000 station you WILL blow the speaker amp in the MSR. An adapter kit was developed to resolve that situation, the RTL4130A. Make sure you either make your own RTL4130A adapter or modify your RTK4043A cable before you meter an MSR. Then put a label on the front of the R1033 saying "WHEN METERING THE MSR MAKE SURE YOU SET THE SWITCH ON THE METERING CABLE PROPERLY" or something like that. Or make yourself a duplicate of the RTK4043 cable kit, with the two pins swapped, and label the unmodified one as "Micor, Syntor, Syntor X, Syntor X9000 mobile radios" and the modified one as "MSR Station". Anybody willing to shoot a few interior photos of an R1033 ?
Cable Numbers: (if anyone has cable schematics or other paperwork please let repeater-builder know).
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Many dispatch systems had the base station or repeater at one location and the control point at another. Setting up or maintaining the connecting phone line required the ability to make both DC and AC measurements. Motorola and Triplett together designed the Model R-1034A Control Line Test Set, and the mixed background of the Motorola 2-way engineers and the telephone telecommunications background of the Triplett engineers shows in the design. This test set, essentially a specialized VOM and an audio generator all in one ruggedized box, measures telephone line current, telephone line noise, DC resistance and both AC and DC Volts, and all measurements are using ranges that are optimized to telco lines. This test set will also send audio tones at an adjustable level and measure received tones in dB on the meter. A switch on the lower left of the panel selects bridged or terminated mode. The unit was built into a sturdy carrying case with a pocket in the lid for the book and the probes, and a snap-hook shoulder strap for carrying. The test set is powered by two common 9 Volt batteries and one D cell battery - and before you buy a second-hand one make sure that you open it up and check for corrosion caused by leaky batteries (this is the voice of experience speaking). Click on the photo for a close-up of the meter panel |
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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. Here's a schematic.  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...
There were also metering kits made for the Motrac / Motran / Mocom-70 / Mitrek series tabletop base stations. While the were a few minor wiring differences, the main difference in the four series of metering kits was the color of the plastic panel behind the switch. Here's the manual for the Mitrek version, the HLN4138A, courtesy of Eric Lemmon WB6FLY. If anyone has the manuals for the others, please let me know.
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.
The TRN5080A test set was made for the MSR2000 series of stations, and has the
functionality of the TLN1857 shrunk down to a small box. The far end top has a
meter revresing switch at the top and the moterint test point rotary switch on
the bottom. The near end has a speaker on/off switch at the top, and a cable
that plugs into the speaker backplane connector at the bottom. The main metering
cable comes out of the bottom.
The MSR2000 station had a similar-styled box that is the speaker only (anybody
have a photo and a part number of it?), but any 8 ohm speaker will work on the
MSR once you add the correct connector.
The TLN2418A and TLN2419A Digital Metering Panel (DMP) was made for the MSF5000 / PURC5000 / MSF10000 station. It also works with the PURC5000 Link Receiver and possibly other stuff. At least one document refers to the TLN2419 as the Diagnostic Metering Panel (DMP).
The full kit includes the meter, flat 40-conductor cable,
RJ45 8-conductor round cable, red and black test probe leads,
and the manual (not shown in this photo). There's an amplified
speaker (with on/off switch) in the left half, a standard 50uADC
meter (with input selector and polarity reversing switches) in
the middle, a two-digit LED channel number display (to the right
of the meter), and address and data switches and a matrix of
digital signal display LEDs in the right half.
Photo courtesy of WA1MIK.
The test cables plug into the front edge.
The TLN2418A Remote Metering Panel (RMP) is identical except
it has blank panels instead of the 2-digit display and the
LED matrix display (it consists of just the amplified speaker
and meter, and their associated switches).
The TLN2418/2419 series has a semi-fatal design flaw, as this email to repeater-builder from Brian Alesio shows:
Nothing like a broken piece of test equipment. Going to a site for emergency repair and finding you've got a bad test set is worse than being bitten by your seeing eye dog. Just passing along an experience related to the TLN2418A and TLN2419A MSF5000 test sets. I have had a test set fail due to secondary damage from being knocked about. You may be able to save future aggravation by opening your test set and re-securing the speaker, which is held in place by push on spring clamps and some not so hefty plastic pins. In my case the speaker detached, slid over and contacted active electronics, which were not to happy for that experience. If yours is not broken, additional insulation on the back of your speaker would prevent this. If some pins are missing, some "Goop" or the like might be helpful to permanently hold the speaker in place.Bob Meister WA1MIK read the above and commented:
Besides those press-on clip studs breaking off and rattling around (the studs are not repairable unless you want to drill holes through the front panel and use #4-40 hardware, which isn't a bad idea), if you drop the test set, it will most likely fall against something on the way down and break one or more of the switch handles. The exact replacement switches are NLA from Motorola, but you may be lucky enough to find a suitable replacement elsewhere.
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Contact:
Mike Morris WA6ILQ can be reached at (callsign) at repeater-builder.com
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 Eric Lemmon WB6FLY, Skip Hansen WB6YMH, Jim Scott N8ORJ, Will Martin KA6LSD, Don Best N6ALD, 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.
