Phonoland

i have a r-92 rowe which the cc aparrently is muting the sound. this was verified by using a friends CCC and it works fine. we even did a eprom swap and no luck with my CCC still. anyway i can fix this on my CCC. cause the ccc works fine cept for the muting thanx

I encountered a jukebox where the muting device quit working when the diodes in the muting board were replaced with exact replacements with the same 1N number.

It turned out that the exact replacements were not exactly exact replacements. During the 30 years between when the jukebox was made and when the replacement was made, the design of the part was changed.

The part was a high voltage diode, designed for use in power supplies over 600 volts. Since technology hadn't at the time hadn't yet produced a diode capable of such voltages, the diode actually contained two diodes in series. The jukebox manufacturer used this undocumented fact: The higher forward voltage of this diode was used to make the muting circuit work.

But as semiconductor doping techniques improved, manufacturers started making the part with a single diode instead of two in series. Thus, replacing the part with the newer part with the same part number results in failure of the circuit to operate as it should.

well in the this case no diodes have been replaced.. still looking for some help thanks

i got this on another reply elsewhere thought id share this info so u dont have to pay someoen to charge u 85 +12 shipping to fix the problem.



The MUTE signal comes from the Central Control Computer MECH connector
P6, pin 17. When it's pulled low, the amplifier is muted. This signal
is driven by the NPN Darlington Transistor Q7 (MPS-A14).

(Quick mute wire test)
If you follow the wire from P6 Pin-17 down to the mechanism, you should
find a male/female disconnect type connector. If you pull them apart,
the amplifier should un-mute.


~Ann Marie ... thanks ann

Your problem could be deeper. You must have the proper part # amp.
The older model amp fits and seems to work, but it could damage the mute circuit in the CCC brd. I believe the diodes in the amp are simple 1N4148's (They used to be 10 for a buck at the shack) If you could
see a schematic, you would see you are only repairing half your problem.
Maybe by sending it to a paid professional, you would get your monies worth, and get it all repaired at one time.

since my friends parts are same partnumbers amps everything ccc all of it thus previous fix is correct.