marantz 4220 (b?) - Rear balance and volume repair

[james weeks]

So I have gotten my hands on a Marantz 4220 possibly b model, I heard someone say there may be a difference, I was hoping someone could guide me in the right direction,

the unit seems to work except the rear channel I guess you would call it, it has little to no volume and the balance seems to not affect it at all, I am using the jack on the front for testing, the rear balance switch can move from left to right with no effect, hope I am explaining this right,

I work on other types of electronics, just have never attempted this kind of repair. just looking for common fixes for this model, any help is appreciated, thank you, guys.

 

[AE Bob]

Are you saying that the rear left right balance control has no effect? What 4 channel mode are you testing it in? It is not uncommon for the rear channels to have little sound, if the source material is in mono, or has little ambient content.

 

[james weeks]

ok, well I just found the service manual, I don't know what mode yet, new to this thing, I am just trying to get the fm or am radio to play from the rear, just its incredibly low even when turned all the way up, balance does nothing, is there a way I should test this to see if it's operating normally? perhaps I misunderstand what rear is for?

 

[wurlyman]

Is the switch on the rear panel in two channel stereo mode or quad mode? If it's in the wrong mode DON"T SWITCH IT WITH THE POWER ON! You'll do damage.

 

[james weeks]

currently, it is on 2 channel

 

[james weeks]

After switching it to 4 channel I see the rear now works, but only in my right speaker, bringing the left balance all the way to the left shuts off the sound completely, and the sound seems to have a high pitched buzz, but I am happy I am making progress, it may be the test speakers I am using that may be part of the issue, I am going to check out the goodwill see if they have something more appropriate, Your advice in this has been amazing.