For the benefit of everyone on the list let me advise all of you concerning the new world of Motorola service; at least when compared to the "old days" when the MSF5000 was considered the top of the line and the "days of antiquity" when the Micor was king. I will not even try to find adjectives to describe the days of the Motrac as the king of the hill as most Motorolans today have no idea what a Motrac was.
***Disclaimer*** What follows is personal opinion and in no way reflects the views of the list owners or others on the list. It is also not a timeline. When Motorola created the MSF5000 they crossed over from the conventional crystal based designs of many years to a new world of microprocessor based design. The letters MSF stood for "Maximum Station Flexability" and the MSF was a very capable station. By using software or the R1800 programmer the parameters could be changed easily in the field, repeatedly. It covered wide swaths of RF spectrum in a single radio. Along with the other microprocessor based radios that Motorola was developing it completely changed the direction that most radio shops were going. The new world of radios created a servicing nightmare. The guy on the bench who had been dealing with crystal based designs and leaded componets all his life now had to decide to either update his skills or maybe look elsewhere. A lot of turnover started to take place in the service environment. And then there was that part about being on a mountaintop with a non functioning radio; how did you drag all the items needed to troubleshoot and repair a PLL circuit based radio with you? Or did you drag the station back to the shop? Motorola made a decision that the generation of station equipment that followed the MSF5000 would be based on the concept of Field Replacable Units. Basically break the radio down into building blocks that can easily be swapped out wherever theradio is located with a minimum amount of effort and equipment. Thus the Quantar radio was designed to be a series of modules in a backplane. Initially no service information was released beyond simple, basic in/out diagrams. A similar philosophy holds true with the MTR2000 radio and will, I am sure, continue into the future. One reason is the complexity of the circuitry and the extensive use of leadless componets and new generation chips which combine a multitude of functions in a single device. Another is the need for specialized test and rework equipment in order to even attempt to troubleshoot or repair the circuit boards. As Eric pointed out, you can procure a Depot level manual from Motorola which will have all the required information and schematics. If you are equipped to deal with high density surface mount rework, then go for it. Otherwise there is the depot. Good Luck Milt N3LTQ ----- Original Message ----- From: Camilo So To: Repeater-Builder@yahoogroups.com Sent: Monday, October 20, 2008 9:15 PM Subject: Re: [Repeater-Builder] MTR2000 UHF Service manual Oh I forget to mention that I did order a service manual from Motorola 6681096E25 its don't have any circuit diagram on it, What is the correct manual number to order that have a circuit diagram. ----- Original Message ----- From: Camilo So To: Repeater-Builder@yahoogroups.com Sent: Monday, October 20, 2008 9:08 PM Subject: [Repeater-Builder] MTR2000 UHF Service manual Need help to order a MTR2000 service manual that have the schematic diagram of the receiver unit, Got this unit from Ebay, Hook up the unit on my bench with a dummy load on the TX out, and apply signal on the RX input with a IFR1200, The squelch open at 0.12 micro-volt at 0.15 uv its 12 DB Sinad, when signal was increased to about 1.0 micro-volts or higher the receiver drop out, as if the agc is overloaded that cut out completely and also drop the TX, Have anyone ever experience this problem before, This is the first time I have seen this kind of problem , and its hard to fix it w/o a diagram. any help is highly appreciated. de w4cso Camilo