I am looking for information on how to retune a motorola micor base station power amplifier(continuous duty) 110W. I think it is built for 470-512, but I want to retune it for 440MHz. I would like to know which capacitors are different between the TLE-1713A and 1714A. Would I just have to replace the capacitors or would I also have to add length/width to the stripline to lower the frequency? What is the easiest way to accomplish this?
Any help will be greatly appreciated.
Retuning Micor Base Station PA TLE-1714A
Moderator: Queue Moderator
My two bits worth:
I have heard of these amplifiers operating at 444, however the last time I attempted this the amp acted like a large attenuator: less power out than the drive. Station met spec @ 461
Since you are so far out of band the performance of the individual modules is highly individual.
The receiver, and exciter may tune up to spec, or may not. There can also be a problem of low drive to the trippler/low level amp. This is usuially caused by the filter in the output of the exciter.
The manual does not allow alignment of this filter, but this was in part because the filter must pass a certain band of frequencies to meet factory specs for the tuning range of the station. I have had good luck just tuning for max output on the channel of interest.
These amps use an alumina sub strate, and can be easilly broken.
I am very familiar with repairing these amps.
The solution is a Henry amp. (or some other brand)
Many parts are NLA, you MUST use "silver bearing solder" (2%)
The reason is that normal solder can disolve the terminals on the chip caps.
While the MICOR in general is an excellent station, there have always been PA problems. That is why several manufacturers have drop in replacements for the PA.
This also eliminates the output circulator which can also fail.
I have heard of these amplifiers operating at 444, however the last time I attempted this the amp acted like a large attenuator: less power out than the drive. Station met spec @ 461
Since you are so far out of band the performance of the individual modules is highly individual.
The receiver, and exciter may tune up to spec, or may not. There can also be a problem of low drive to the trippler/low level amp. This is usuially caused by the filter in the output of the exciter.
The manual does not allow alignment of this filter, but this was in part because the filter must pass a certain band of frequencies to meet factory specs for the tuning range of the station. I have had good luck just tuning for max output on the channel of interest.
These amps use an alumina sub strate, and can be easilly broken.
I am very familiar with repairing these amps.
The solution is a Henry amp. (or some other brand)
Many parts are NLA, you MUST use "silver bearing solder" (2%)
The reason is that normal solder can disolve the terminals on the chip caps.
While the MICOR in general is an excellent station, there have always been PA problems. That is why several manufacturers have drop in replacements for the PA.
This also eliminates the output circulator which can also fail.
Aloha, Bernie
I only have the final PA (TLE1714A) from a 100W base station.Since you are so far out of band the performance of the individual modules is highly individual.
This is just the base station final amp (TLE1714A) the part on the large heat sink. I was told that it needed approximately 3 watts input for full output (about 100W). However, it is the 470-512 version and I don't know if it will work between 440-450.
I am very familiar with repairing these amps.
I haven't had a chance to try it yet, but if it doesn't give any/full output, is there anything I can change, such as: adding to the stripline to lower the frequency that it is tuned for? There aren't any variable capacitors in the final PA section that I have. I would appreciate any information that you can give me.
My two bits worth:
Do not drive with over 2 or 3 Watts or you will fry the input stage.
The yellow wire is the Power control line, which should be at 7 or 8 volts.
The left BNC cable is the input.
Try it and see what happens...
Some of the micro strips have different part numbers between the 450-470, 470-512 models.
Your amp is rated at 60W, which includes the output circulator losses.
The amplifier components are the same as the Micor mobile.
It may be possible to build an amplifier by replacing the parts that differ between the two models by canabalizing a mobile.
Personally, I think you have a very nice door stop.
Do not drive with over 2 or 3 Watts or you will fry the input stage.
The yellow wire is the Power control line, which should be at 7 or 8 volts.
The left BNC cable is the input.
Try it and see what happens...
Some of the micro strips have different part numbers between the 450-470, 470-512 models.
Your amp is rated at 60W, which includes the output circulator losses.
The amplifier components are the same as the Micor mobile.
It may be possible to build an amplifier by replacing the parts that differ between the two models by canabalizing a mobile.
Personally, I think you have a very nice door stop.
Aloha, Bernie
"Personally, I think you have a very nice door stop."
Well, the heatsink is good for something.
I think the drive is about up to one watt
I have gone in adn bypassed the "SMALL" circulator stage in the PA, mostly because the external ones have a LOT less loss and generate less intermod.
That should help. Maybe a few added caps on the PA stages to lower the freq. would help too.
Like Bernie says, mostly the same as the 60 or 100 watt mobile Micor.
If you use the correct solder, they usally last forever.
Well, the heatsink is good for something.
I think the drive is about up to one watt
I have gone in adn bypassed the "SMALL" circulator stage in the PA, mostly because the external ones have a LOT less loss and generate less intermod.
That should help. Maybe a few added caps on the PA stages to lower the freq. would help too.
Like Bernie says, mostly the same as the 60 or 100 watt mobile Micor.
If you use the correct solder, they usally last forever.