Marantz 4300 right channel intermittent and distorted

[Carl bradley]

I recently sent my Marantz 4300 to get recapped, after a year of waiting and frustration I finally received it back. One month later my right channel comes on for a second starts distorting and cuts out again and when I push the FM mute button the radio cuts out. Can anyone give me an Idea of where to start troubleshooting? I really afraid to put it back in the shop.
I connected it to my 4270 and it seem to be on the pre-amp side. My question is If I connect a pre amp should it be another Marantz or can I go with a newer unit like a Acoustic research amp or a Rogue Sphinx v3 amp.

 

[PETERDECO]

Before you do anything, clean all the switches and controls with contact cleaner. If you see any PC mounted trimmer pots, give them a blast too, without turning them.

 

[Martaine2005]

when I push the FM mute button the radio cuts out.

Do you have an adjustment pot on the back somewhere? Some do.
Perhaps the tech adjusted it?
For simplicity, you might want to check what caps were used and where. I know some techs that only replace some, not all.
Did you get a receipt with the information on?

Martin

 

[Carl bradley]

Unfortunately I didn't get any details of what was changed only got a small paper with the final readings (specs) after completion. I made the mistake of ordering this service on e-bay with crosspath vintage and paying up front I called them to request for help and got no response. I do not have any pots on the back.
But I will take the cover of next and spray De-ox-id on the pre-amp trimmer pots. Thanks for the response.