Marantz stereo receiver repair project.

Hello.

My friend has recreantly inherited his fathers very first amplifier, a Marantz Stereo FM/AM Receiver, Model 1515.
It does work although there are some problems like sometimes only one speaker works and sometime both works and there are some bad connections and noisy potentiometers. I am looking for advice on what can be and should be done to treat it as good as possible, we will take and dissemble the hole thing and really clean it and I plan to buy replacement components for some obvious stuff.





The brown mark on the inside of the chassis is the spot right above the two main bulk capacitors... Good sign.

We are going to go over the boards thoroughly and inspect all components but first of I am thinking of all the larger electrolytics, I was hoping that there are some things that one usually should do with old amplifiers like this.
The potentiometers are very specific and hard to replace I now that there are sprays that can improve them, what would you suggest?

This amplifier has a great sentimental value for my friend and although we don't have any hugh amount of money to spend we have some and want to make it as new condition as possible and any and all thought about this is greatly appreciated.

Regards

Replace the pots with same value high quality pots and do resoldering of all dry solder contacts.

Before replacing the pots, which are likely to be obsolete, flood their insides with switch cleaner and twiddle them from end to end. It should be a 99% cure. BTW the reason pots go noisy is the DC applied to them via leaky coupling capacitors, so if the problem persists you should have a look at them.
Frank

DeOxit seems to be the recommended cleaner for pots by the audio community.
https://www.audiokarma.org/forums/showthread.php?t=207005

The large electrolytics may also be leaking by this time. Look for any bulging on the tops and replace any with this appearance.

In receiver switched-off state you could test the electrolytics with a (current limited) voltage source and an amp meter. Check with max. Elco voltage. Look out for correct polarization.