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Marantz 4400 no lights.....?

I tested the rear channels.....they work normally. ONE rca input.....balance works fine...when all the way to one side there is sound...all the way to the other side...no sound. That is normal.

So, where the heck would the signal 'combine' from ONE rca input to giving sound on both front channels?????
 
Switches, pots an'all are squeaky clean....cleaned multiple times.

The BIG funny thing in this situation is the LEFT and RIGT sound output with ONLY one rca(left out from cd player) connected........this is the strange thing.....where could the signal get combined. When I put the left-out of the cd player to any L/R input of tape1, tape2 and aux....I have friggin sound in both front channels......balance works fine.


I am having a real hard time tracing the signal on the scat'.........

How are the amps configured? LEFT side......FRONT LEFT and REAR LEFT?
 
I'm not saying clean your pots- I'm saying check the mechanicals of the input selector- I do not believe there's anything "electronic" involved in a right and left channel issue- it's mechanical.
 
You don't have the 25mm long screws for the wood cabinet being used on the chassis feet on the bottom with no wood case do you? Worth a check! They can get into jack contacts and cause fun stuff to happen.

I do have a 4400 at home and don't have the issue of front inputs combining so you definitely have an issue.
 
Can you list what work was completed on the unit since this issue started?

Such as recaps and what boards....or transistors that were replaced.

And list them in chronological order.

JohnK
 
I am travelling atm............will be back with the unit on the 15th May.

All is recapped.......................except big filter caps.
 
Ok....I am back with the 4400........I am quite baffled by the symptoms the unit has. With just 1 rca(left) connected to the aux( or tape 1/2), I get sound in both channels. What the heck could cause this? What does the phase inverter board do? All my caps are correctly set......checked and double-checked.
Does the aux input go through the mpx board? Dolby boards?
 
Check my post #48 and check those screws.

The phase inverter board takes the two channels of stereo audio and makes an electrically inverted version of each for use in the 2 channel mode. The non-inverted signal drives one amp section on a channel which is routed to the '+' speaker terminal and the inverted one drives another amp section which is routed to the '-' speaker terminal. Since there's now signal on both terminals out of phase you get twice the volatge across the speaker. This is called bridge mode sometimes. I may have the speaker '+' and '-' crossed in the explanation above but you get the idea.

The aux doesn't go through the mpx board, only the FM does.
 
Post #48 has just 'popcorn'.....?

Edit:...I checked post#46..........screws are checked......areas are good......will check again though.

Could the phase board 'combine' the single signal?
 
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Oops, I did use the wrong post number, sorry! That board can't combine signals unless there's a short on it somewhere. I'd guess your issue is a short somewhere, like at a switch, maybe the 2/4 channel switch on the back panel maybe.
 
I may have a problem with cap ce17 on preamp board. I re-soldered and continuity tested..all ok......except with the amp ON, I can hear crackling in the left channel when I touch(with a wooden probe) the cap.

I managed to remove the sound in the left channel(with 1 rca connected to the RIGHT input).......so, now I have sound in the RIGHT channel and none in the LEFT. That is good.......kinda'~....because, when I switch the input rca to the LEFT input, I still have sound in the RIGHT channel and none in the LEFt......'scratch head'!!!!!

Anyway...I think it is narrowed down to a preamp problem. The diodes on the board have not been changed. Could a 'leaky' diode cause the above and earlier symptoms?
 
Well the easiest way to help remotely would be a list of work preformed to the unit. What was touched and why.

Not unless you bought it this way.

Jk
 
jk.....check a few posts back. The unit has been recapped...except the big filters. 4 sk30's have also been changed on the diode matrix board...thats it.

The weird thing is the sound output in ONLY the right channel with 1 rca input in either left or right aux input.
 
Could my problem be something to do with the mono button? Would that 'combine' my signal and give me the symptoms I am experiencing?
 
You may be onto something since the mono button would take either input and put it on both outputs if on or stuck on while looking not stuck. I thought you had DeOx'd this unit though?
 
The unit is totally de-oxited. The mono-button is actually a rotary switch.....de-oxed multiple times...........I don't get it.......

I am back to looking at the pre-amp/tone amp boards again..........in my unit cd9-12 were 4.7uf bipolars on PD01....in the parts list they are 'normal' caps....what should I use in there place?(I used 4.7uf/35v bipolars)....
 
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