2215B weak channel

[Stink Bear]

I have a newly acquired 2215B that has a channel problem. I'm new at working on stereos, I would like to learn and I know a little about electronics, but still really a novice. IIRC the right channel was weak and quite distorted the first time I powered it up, I cleaned the switches and pots with Deoxit 5, now the right channel is very weak.
I took the heat sink off the main amp, I was going to de-solder the output transistors and check them but I decided to think things out a little bit more first. I don't see any burned components on the amp board.
I would like to do more to isolate and am considering de-soldering the pins and swapping J701 & J702 (main amp input - L&R) to see if the problem stays on the right side or moves to the left. I figured I might as well hit up the experts and see if anyone has any thoughts on other, possibly easier ways to narrow down the problem more before I start removing and checking components.
I cleaned the pots and switches again while I have it apart and I'm thinking about this. The unit looks like it got wet and has some minor corrosion issues.
I don't have a signal generator but I do have an O-scope that I got recently, I haven't used one since I was in tech school in the early eighties, and I didn't use one much then. If there's something I could look at with the O-scope and someone would like to try to instruct me on how to do it I would give it a shot.
Any thoughts or advice would be appreciated.

 

[Stink Bear]

Output transistor.

 

[blhagstrom]

FWIW, I just worked on a 2215, non B. One channel was weak.
The owner wanted it recapped.
The recap of the amp fixed it.

I recently did a 2015 and found bad caps on the amp.

Those Marantz at getting old enough that a recap is almost necessary.

 

[Steven Tate]

The 2215B would be a good receiver to start learning about recapping/refurbishing. If you decide to work on it yourself and you don't have a lot of experience, here are three tips to get started:

1) Before starting, search on all threads in the Marantz forum related to the 2215B. There likely is a lot of information that will give you a leg up on your rebuild. Someone might correct me, but I think the B model is very different from the non-B so info for the non-B might not apply to your unit.

2) Build a Dim Bulb Tester and never fire the unit up after changing something without being on the DBT. If something is shorted, it will indicate it and might save a bunch of components

3) Read Echowars' great thread on getting started in audio repair. You won't need an oscilloscope or signal generator just to get started. But if you get addicted (and you probably will), you will want those eventually.
http://audiokarma.org/forums/index....udio-gear-eh-heres-the-tools-you-need.333423/

There is a vast well of experience in the Marantz forum, so don't be shy about asking questions. I started from zero about three years ago and with much help from experts, have rebuilt over a dozen units, including some of the big boys. But my knowledge base has gone from about zero to a 10, while we have several experts that would be 100's for sure. Good luck!
Steve

 

[Stink Bear]

Thanks for the tips guys. I think I'm just going to get the channel fixed for now. I'm already hooked. I have several units that I am working on. I think my first re-cap is going to be an SX-990. I would like to get proficient enough to feel confident tackling my SX-939. I built a DBT, I will try to remember to use it after I replace the output transistors. This is interesting stuff, I'm starting to learn a little about how amplifiers work. From my limited experience it seems amps are a common problem, especially the outputs and drivers.