Marantz PM-230 Amp repair help - Input selector?


2013-04-05 11:24 am
Hi all,

I've recently bought a Marantz PM-230 amp from ebay for very little money, but have found the device to be faulty.

Basically, there is zero output from the speakers from any of the inputs. I am pretty sure the fault lies in the input selector, as the lights indicating the active inputs work fairly erratically; they don't respond to the corresponding button, and turn on in random arrangements each time i power up the unit.

While I am a novice in this sort of thing, I am prepared to get my hands dirty and my soldering iron out to try and repair the thing, as i paid so little for it and am keen to learn.

I've opened up the amp to see of there were any visual defects, blown components, bad connections etc, but nothing seems wrong. I also checked out the schematic and everything seems to match up properly.

I found this thread It lead me to believe that it could be one of the input selection ICs that has failed. The one in question here is IC7815. I've tracked down and ordered a replacement.

Does that seem like an obvious reason for the device to be faulty?
Are there any things i should check before attempting an IC replacement?

While I am inside the amp, should I consider any other replacements/upgrades?

Thanks for your help :)
I have exactly the same fault!!!!

Dear friend I have seen your post and believe it or not I have the exact fault in my Marantz PM 230 where I believe have got the same faulty IC LC7815.

My whole System that is the Record player , the Tape Deck ;the Radio tuner and the power Amplifier I have bought them new about 18 years ago.

The fault is exactly like yours and is coming from the selector which is malfunctioning and after I opened the amplifier I have found that there is an IC
LC7815 which control the selector and I believe that it is 99% is faulty.

May I ask you from where I can order this IC and did you manage to fix your Marantz Amplifier.

Thanks in Advance and kindly answer me please

Anthony Borg