Hi
My friend brought to me 2 of these amps to fix. One works with all inputs(CD,Tuner,Tape,Phono,etc). The other plays only the CD input, all others have no output. This amp at times plays only the CD input even when you select other inputs. If I select the PHONO input, the front PHONO indicator lights up, but the sound is still from the CD. I could not get a schematic for this amp. It uses a TMP87CH46N-1k40 micro controller and 2 input selector ICs (LC78212 and LC78213). The 2nd amp at times seem to work OK, plays all inputs but when you OFF and ON back the amp later, the problem comes back again. I am confused at what is causing the problem. Please assist.
Thanks
Carlos
My friend brought to me 2 of these amps to fix. One works with all inputs(CD,Tuner,Tape,Phono,etc). The other plays only the CD input, all others have no output. This amp at times plays only the CD input even when you select other inputs. If I select the PHONO input, the front PHONO indicator lights up, but the sound is still from the CD. I could not get a schematic for this amp. It uses a TMP87CH46N-1k40 micro controller and 2 input selector ICs (LC78212 and LC78213). The 2nd amp at times seem to work OK, plays all inputs but when you OFF and ON back the amp later, the problem comes back again. I am confused at what is causing the problem. Please assist.
Thanks
Carlos
I am having a similar kind of issue. A friend of mine who lives quite far away wants to sell his Marantz PM 6001 to me. I would love to buy it but he says only CD input works. I am afraid that I won't be able to fix this issue. He of course doesn't have a single clue about it. I spoke to my repairman and he says if it is an analog type selector switch there is hope but if its something that works digitally with pulses, it is difficult to get it repaired.
The Amplifier uses two LC7812 input switching integrated circuits.
There is a high probability that the integrated circuits have failed IC21 / IC22.
If you remove them check the plus and minus 15 volt supply rails, before fitting the newICs.
There is a high probability that the integrated circuits have failed IC21 / IC22.
If you remove them check the plus and minus 15 volt supply rails, before fitting the newICs.
Thanks for your answer. That means most likely the amplifier has failed IC's. The one I mentioned above.