Marantz 3200 Tone controls not working.

[Midwestside]

Hello all,

I posted a different 3200 thread awhile back. I wasn't able to properly describe what was happening, couldn't delete it , so i thought i would start a new post.

My 3200 (new to me) seemed to play bass and mids out of one speaker, and normal in the other.
Not being familiar with the tone controls on this thing i ended up switching it to "out' and then all
of a sudden the unit played normally in both channels.( which i can live with in the long run)
But I guess the tone control knobs being switched to any other position, "in" or the other filters.
causes one channel to be muddy / weaker. Also switching the tone control knob around creates a loud pop.

I would like to have a go at this myself. Any ideas where i should start looking?

 

[rBuckner]

Electrolytic caps. Some poor old boy has dried out and is leaking.

 

[Midwestside]

Ok, here are the boards. Maybe someone could point out some needed attention areas on cap replacement. I do see some old ones here, esp on the power supply board.

 

[rBuckner]

Yeah, I'd start with the power supply. The one in the very back has the plastic sleeving pulled back fairly far. That would be due to the internals swelling and pushing on the rubber plug on the bottom end. But replace 'em all. But my thought was something ore in the audio path but if the power supply is off it can cause all kinds of weirdness.

 

[Steven Tate]

If you don’t have a service manual, get one. You don’t want to dig into one of these without it. It will tell you what board is what and what components go in each spot. If you don’t have one, you can get it at hifiengine.com (free membership required). Go to Library—>Marantz—>Preamps—>3200 to find the service manual.

 

[quadmatrix82]

Transistors on the tone board are worth changing they create noise issues not related to your current problem

 

[Midwestside]

I did find a service manual and ordered all the caps to do the power board and tone control board. Perhaps i will go back and order some transistors.

 

[Midwestside]

Well so far did all the caps on the power board.
Most recently i was hearing some noise coming from one channel in quiet parts between and during music.
Using a bamboo skewer, i probed around around on some of the other caps. I was able to get a good screeching sound wiggling the 2 orange 4.7uf caps on the relay board.
I just went ahead and replaced all the caps on that board. Now its dead quiet. Tone controls slightly improved, however , a full go through and replacement of the tone board will probably be what i need.
I will go ahead and order transistors as well Quadmatrix82.