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Post by spetersen on Nov 5, 2022 19:44:22 GMT
Hi, I was given two 06-07438-04 125 watt amplifiers to repair for an R88 jukebox. I found some info on the volume control connection, but I'm not sure if it is correct. it says connect pins 1+5 together and connect to one end of a 10K pot, connect pin 3 to the wiper, but it does not say what to do with the last pin of the pot, does it hang, or is it grounded? also does the mute plug need to be connected to run the mp out of the box?
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Post by spetersen on Nov 15, 2022 1:53:27 GMT
I found out what I need to test them, but I was wondering what goes wrong with the preamp that causes full volume without the control connected? Is it a certain IC?
Thanks, Scott
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Post by jukenorman on Nov 15, 2022 11:29:23 GMT
Hi Scott,
I don't work on these but there are previous threads that might help you if you look back or search this forum.
Norman.
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Post by spetersen on Nov 15, 2022 12:35:25 GMT
Thanks for the reply, but I've don extensive searches, and I have not seen any info on diagnosing the preamp. I have the service manuals, and I don't see any info other than the schematics, and basic voltages.
I found the service manuals online, I was able to repair both amps, one was bad solder joints, and blown outputs, the other was bad "thermisters" which are 28v 40ma light bulbs which break at the wires that attach them to the board
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