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2325 FM at 1/2 volume

runningdog

runningdog

AK Subscriber
Subscriber
I'm working on a 2325 that has about 1/2 normal volume when on FM.
  • The tuning meter does not work.
  • The signal strength meter shows strong reception.
  • The P200 IF board has been rebuilt and triple-checked for soldering/parts issues.
  • It is not the P300 M MPX board as it has been swapped out for a working untouched board with the same results.
I have a working 2325 and I'm going to start doing some comparative measurements at the inputs and outputs of the FM MPX and IF boards. Your suggestions and questions wanted, please.
 
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check your dolby to make sure its off.;)
i will check a schematic and see if we can where the meter is being fed from. Maybe there is a connection
This is interesting,
upload_2016-6-12_17-57-52.png

Work that multi path switch in/out a few times and watch that meter. see if its capable of altering the needle.
The 200 board L201 (Third winding portion of L201) feeds its signal to J204.
The thing i would suggest is to perform the dolby adjustments and follow the service manual. It looks like the dolby input source adjustment is done last, But i am not sure if that adjustment determines final fm output levels, or if it is strictly just a pre-dolby amp adjustment. Hopefully someone with more knowledge will jump in and help.

upload_2016-6-12_18-2-2.png

upload_2016-6-12_18-3-5.png

I would question why the adjustment would be so out of whack, being that both sides are evenly quieter.
The bigger question is did this have this problem before the 200 board was restored?
You may find that the 200 board is used in 2275's and 2330's and if your really ambitious, you could swap a board for a test, if you have one. Just mark down your pin # and wire colors before pulling it out. Heat the pins and pull the pins with the wires still attached.
 
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After taking a break on it this 2325 is back on the bench.

KutzlerTrans said:
The bigger question is did this have this problem before the 200 board was restored?
Click to expand...
I test after each board and I believe this started after doing the P200 board and before doing the P300.

When Dolby is on it seems to work OK. I'll take a closer look at the Dolby adjustments...have not done them before. And I'll look at swapping out the P200, that should be telling.
 
KutzlerTrans said:
and if you're really ambitious, you could swap a board for a test
Click to expand...

I swapped out the P200 board and all is well. Of course I still need to rebuild this one. Oh, and I would not have swapped them by pulling out the pins. That worked really well with this kind of pin. Fast and it looks good when completed.

KutzlerTrans said:
Make sure your pins are all soldered in on that 200 board.
Click to expand...

I turned a couple of them upside down so there was plenty of pin sticking through to solder to.
 
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