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: [email protected]
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: [email protected]
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
