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).
Click on the image above for a larger image (576KB).   Photos by Tim Ahrens W5FN

A view of the exciter and receiver card(s). From the left is the exciter, the second receiver and the primary receiver.
Most MSRs will not have the second receiver.
Click on the image above for a larger image (457KB).   Photos by Tim Ahrens W5FN

The MSR2000 is a base or repeater station that was a follow-on to the Micor line, and was available only in VHF and UHF. It is basically a second-generation Micor station control shelf mated to the receiver and exciter sections of a Mitrek mobile, mated to 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), and the RF sections are separate receiver and exciter sections. 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 pinout before you go to the trouble of changing the connectors.

The MSR2000 is a non-synthesized station, and uses receiver and exciter modules that are derived from the Mitrek mobile radio.   The frequency-determining component is a self-contained oscillator-tripler plug-in module called a Channel Element.   When you move an MSR from one channel to another it requires cutting a new crystal for the receiver and a second for the transmitter.   This article is worth reading: Why should you really 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.

The documentation for the MSR station consists of two separate manuals: an RF manual (that is frequency band dependent) and a "Control and Audio" manual, a full list is below.   At the time of this writing (mid 2009) the RF manuals were out of stock (but are PDF'd below) and the "Control and Audio" manual was still available for US$55-$60.   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.   Click here for instructions on how to order manuals.

As far as I can tell from the manuals, the model number 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
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]	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

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" and remove it from the cabinet (which could be sold to someone else).
2. The frequency range (the "split") is not encoded into the model number. To determine if you have a (for example) 132-150 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.
3. There is no practical way to change an intermittent duty cycle radio to a continuous short of replacing the power supply and the PA deck.
4. The MSR manual refers to the GS 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 MSR-2000 Base can be converted for duplex repeat operation, it's just that something designed and built to run full duplex from the factory is 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 basically a 120v AC supply minus the power transformer and bridge rectifier - just a 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). The TRN5073 is the duplex PL board, the TRN5074 is the simplex PL board (and the TRN5076 is the duplex DPL board, the TRN5077 is the simplex DPL board, and there is an article on this web site on how to make your own TRN6005 DPL code plugs).
7. A "0" is a very rare beast as the market for wideband radios is very limited. It was a special order for the broadcast industry as some stations still had VHF and UHF remote pickup channels at the time these stations were current products.
8. The base station (simplex) 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.
10. Does anybody have any information on the "A" or "D" configurations?
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 shipped with.

Station Notes

• If you mangle a pin on a receiver or an exciter module beyond salvage the 10-contact connectors are part numbers 28-83254N01 (male) and 29-83497F05 (female).
• Receiver and exciter part numbers:
  

  VHF
  Model number (with A or B suffix) (see note)	Frequency MHz	Filtering (see note)	Module	Mode	Module Connector	Notes
  TLD9231	132-150.8	No	Exciter	Simplex	Female
  TLD9232	146-174	No	Exciter	Simplex	Female	See photo below
  TLD9241	132-150.8	Yes	Exciter	Duplex	Male
  TLD9242	146-174	Yes	Exciter	Duplex	Male
  TRD6171	132-150.8	No	Receiver	Simplex	Female
  TRD6172	146-174	No	Receiver	Simplex	Female
  TRD6181	132-150.8	Yes	Receiver	Duplex	Female
  TRD6182	146-174	Yes	Receiver	Duplex	Female
  TRD6191	132-150.8	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  TRD6192	146-174	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  TRD6302	146-174	Yes	Receiver	Duplex	Female	See photo below
  If there are any I missed, let me know and I'll add them.

  
  
  

  UHF
  Model number (with A or B suffix) (see note)	Frequency MHz	Filtering (see note)	Module	Mode	Module Connector	Notes
  TLE5502	450-470	No	Exciter	Simplex	Female
  TLE5512	450-470	Yes	Exciter	Duplex	Male
  TRE6152	450-470	No	Receiver	Simplex	?
  TRE6162	450-470	Yes	Receiver	Duplex	Female
  TRE6172	450-470	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  TRE6153	470-512	No	Receiver	Simplex	?
  TRE6163	470-512	Yes	Receiver	Duplex	Female
  TRE6173	470-512	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  TRE6262	450-470	Yes	Receiver	Duplex	Female
  TRE6272	450-470	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  TRE6263	470-512	Yes	Receiver	Duplex	Female
  TRE6273	470-512	Yes	Receiver	Duplex	Female	10.8 MHz offset IF frequency
  If there are any I missed, let me know and I'll add them.

  Table notes:
  1) The trailing "D" in the three-letter part number prefix is VHF, "E" is UHF.
  2) The "filtering" on the exciters and receivers consists of individual RC networks on the pins. All of the PC boards are etched for them, the non-filtered units have jumpers. Look at the schematics for the parts values then suck out the solder and the jumpers and pour in the parts.
• 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.
  
• There are at least three 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.
• 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 Klixon 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 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 Interfacing document for a diagram on how to use one Klixon for both functions.
  
  
  This is one way to fan cool an intermittent duty amp.
  
  
• The early "A" versions of the PA would fail if you looked at it cross-eyed. The B version 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 406-430 MHz version, there's the 450 to 490 MHz range, and there's the high range 485-512 MHz range.   And there is no way of changing a 406-430 MHz or a 485-512 to 450-490.
• The MSR station has been known for intermittents in the blackplane, especially if a connector pin is bent and then straightened (the force used to bend and then straighten the pin frequently cracks the solder). Use a good strong magnifying glass and check the backplane pins on the card socket for cracks between the pin and the trace. This is especially true on audio connections - the audio can change in level, become distorted, etc. The fix is simple, use a long thin soldering tip, put a tiny bit of flux on the surface of the solder then reflow it. This is also true of the pins on the receiver, exciter and PL board, in fact on any card slot that has a card inserted.
• Note that the MSR-2000 station does not have a built in speaker - it's either in a small box that plugs into the backplane, or it's part of the test set.   You can connect a regular 8 ohm mobile speaker with no problems.   Just plug it onto the back of the R1 Audio card slot pins (pins 22 and 23).
• The parts list calls for a KLN6209A reed as a decoder and your choice of a KLN6210A or a TLN6824A as an encoder.   I've used a pair of 6209s and a pair of 6210s in the field and not noticed any difference.   I've also used a K-1000 reed and not noticed a difference.
• 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 multi-PL tone decoder module for the card cage is the TRN5329x (where x is blank, A or B indicating the hardware version).   When used in the stock repeat shelf, this card allows the repeater to respond to up to four additional 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 the second (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 would allow autopatch 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 TLN5745x Multi-PL Decoder (again, where x is blank, A or B indicating the hardware version).
• The local speaker volume control 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.   The real pot can be mounted into the endplate then you run three jumper wires from the pot terminals to the circuit board where the original pot used to be.   Mount an LED into the old hole using a mounting clip and wire it to the COR line per the VE6SBS mod info below and you'd think it was Moto stock.
• A regular Mitrek / Micor / Syntor mobile microphone can be plugged into the front of the receiver control card 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, the card is on an angle because the left hand card guide is broken.

Useful MSR-2000 Manuals, etc.       Click here for instructions on how to order manuals

Prices quoted below are Moto "NSO" Pricing ("National Service Organization") - the prices that Moto charges their service shops. Pricing to the public may be higher. Prices are changed quarterly, so use the mentioned prices only as indicators.

• 66C84230K01 = the official MSR2000 tuning tool.   GET ONE (or two)   A cracked slug is not worth the few dollars it costs. If you are new to the MSR I'd get two, and leave the second in it's little envelope in the tool box. Then when you break #1, you unwrap #2 and put the wrapper in your pocket. That night, at home, when you empty your pockets you will find the wrapper and that will remind you to order #3.
• TLN5935A = the extender board for the plug in control cards. You won't need one until you need to service a card, then it will be invaluable. Until you find one, you can try what a few others have mentioned to me in the past: tilt the card cage down and plug the card onto the pins of the back of the socket. Somewhat flimsy, but doable.
• 6881061E40 = Control and audio (no RF), still available (as of mid-2008) from Motorola for about $57
• 6881061E50 = VHF RF, Power Supply, and Accessories Manual.   When it was available this book was about $52... see below for PDF files.   If you want a paper copy try your local 2-way shop or eBay).
• 6881061E55 = UHF RF   No Longer Available from Moto, but see below for the PDFs.   Yes, 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). When it was available this book was about $40.
• 6881062E47 = Battery Charger Power Supply Option C28AN (you only need this if your station has a TPN1192 series power supply) NLA, but the PDF is below.
• 6881114E65 = UHF Preamplifier TLE2403 NLA from Moto but PDF'd under the "UHF accessories" below (you only need this manual if your station has this option, and frankly AngleLinear makes a much better preamp)
• 6881114E66 = VHF Preamplifier TLD2611A (ditto) NLA
  
  Here's a photo of a TLD2611 high band preamp
  (which is also used in the Mitrek and Syntor mobile radios)
  Don't forget to cut both ends and remove the jumper adjacent to the preamp pins if you install it
  
  So you see what looks like a white resistor and labeled "J102" above the brown connector in the bottom of the slot? That's it.

The following sections from the MSR2000 VHF Service Manual (6881061E50) were scanned and submitted to Repeater-Builder anonymously. Click on each one to download it.

• The entire 6881061E50-B VHF manual   17.6 MB PDF file
  The entire 6881061E50-B VHF manual   46.3 MB PDF file - a better resolution scan, but a MUCH larger file
  Note that both of the above files are just the RF sections, you need the 6881061E40 Control and Audio manual as well.
  
  
• MSR2000 Battery Charger Power Supply   7.9MB PDF file
  You only need this if your station has the C28AN option. Just look at the power supply chassis and locate the TPN number stamped on it. If yours is the TPN1192A supply then this file is the complete manual on it.
  
  
• MSR2000 Standard Power Supply   4.8MB PDF file
  This is the documentation on the standard supply, model number TPN1191A
  
  
• MSR2000 VHF Accessories   4.3MB PDF file
  TLD2502A high band duplexers, TRD6210 and TRD6270 two-receiver multi-couplers, TRN5079 and TRN5080 test sets, TMN6054A microphone, and a few other useful items
  
  
• MSR2000 VHF Continuous-Duty PA   3.5MB PDF file
  TLD2601A, TLD2602A, TLD2603A PAs, and TRN5122A and TRN5571A Antenna Switches
  
  
• MSR2000 VHF Exciter   4.3MB PDF file
  TLD9231A and TLD9232A Simplex, TLD9241A and TLD9242A Duplex
  
  
• MSR2000 VHF Intermittent-Duty PA   3.9MB PDF file
  TLD2532A
  
  
• MSR2000 VHF Receiver   3.3MB PDF file
  TRD6171A, TRD6172A, TRD6181A, TRD6182A, TRD6191A, TRD6192A
  
  
• MSR2000 VHF Transmitter Alignment   4.6MB PDF file
  Covers both intermittent and continuous duty models

The following sections from the MSR2000 UHF Service Manual (6881061E55) were scanned and submitted to Repeater-Builder anonymously. Click on each one to download it.

• MSR2000 UHF Accessories   6.1MB PDF file
  TLE2403 Preamplifier, TLE551A receiver multi-coupler, T4084A, T4085A, T5002A, TLE2351A, TLE2363A, TLE6386A duplexers, TRN5864A antenna switch
  
  
• MSR2000 UHF Exciter   5.3MB PDF file
  TLE5502A Simplex, TLE5512A Duplex
  
  
• MSR2000 UHF PA   5.9MB PDF file
  TLE2283A and TLE2284A PAs and TRN5864A and TRN9168A Antenna Switches
  
  
• MSR2000 UHF Receiver   5.4MB PDF file
  TRE6162A, TRE6163A, TRE6172A, TRE6173A
  This file is missing the part number pages.
  
  
• MSR2000 UHF Receiver Parts Lists   177KB PDF file
  TRE6162A, TRE6163A, TRE6172A, TRE6173A
  These are the missing the part number pages.

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

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 MSR-2000® 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.