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Marantz 4400 no lights.....?

I changed all the sk30's on the diode matrix board. Are there any other areas on that board that could be suspect?
 
jstang said:
Solder bridges or whiskers....
Click to expand...

I am having the same issue with my 4400. Except my scope only displays the X axis near the top. It (the display) seems a bit brighter though than the OP's. I had my stereo tech look at it and he said it was likely the power supply board and replaced a FET but still nothing. I am going to bring it to another shop that is a Marantz service center and has been since the 70's so they have worked on these but am wondering if the scope is shot?
 
OK your're right. He said that he replaced the transistors but still nothing. He is not charging for the effort so at least I am not out anything. The other place sounds pretty confident that they can fix it so that is reassuring that the scope is not shot.
 
These 4400 aren't easy to work on, throwing parts in it without knowing what is wrong is just a waste of time IMO. Take it to a shop that is familiar with the 4400.
 
Well.......found one broken wire to the matrix board.....j05.....fixed. should I change the diodes? Are they 'weak'? Will IN60's do?

I still can't find the reason for the 'blending' of 1 rca input to 2 main channel output......

(damn machine!!!!!.....)
 
Well some one was in working on matrix board, so look for solder bridges or whiskers... Test before you replace the diodes.
 
jstang.....I have completely gone over the diode matrix board.....it is ok.

I have been using some stereo test signals from the 'net. I am now quite sure, that I don't have stereo.......not even when STEREO is indicated when playing FM.

Now.......where in the unit is STEREO made? Either for normal(aux, phono, tape) inputs....or FM(MPX board?)

We MUST be getting close to solving this...........................
 
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Could the problem be on the buffer amp/preamp board? Somehow FL and FR are being blended..........
When looking at the buffer/ preamp board....how are the channels positioned. Is it LR-LF-RF-RR? As the rear channels work normally.......I am guessing my problem lays with 'middle' part of the board.....?
 
Darn!,,,,,,,,,still haven' t got me'self a scope..............it is probably time to give in and invest in a scope.
But, now that I don't have a scope............any good ideas would higly appreciated!
 
The signal is getting through(to the amps).......just getting blended on the way.....I dunno'............damn shame to give up on this nice amp.......
 
bk.....what would you do with your scope? Where and what would you hook-up to? Just give me an idea.

The problem is ONLY affecting the front channels...............
 
I'd inject a signal into the front AUX and trace PE01 to see if it's going into the pre and coming out. The same sort of issue happened with Kyle and his 4400.
 
Bk...ok.....that sounds good. The signal is getting through all the way to the speakers. It does not matter which single FRONT rca input I use.........aux, tape, etc.......I get '1 in and 2 out'.
I think the signal is getting blended on the buffer amp/preamp board.....it cant be anywhere else. I have checked and rechecked all switches/pots/etc...all are ok. I have not touched any of the selector switches....they are intact....no loose wires etc. Those switches are a nightmare to behold! Friggin wires all over the place!

Also....when looking at the block diagram in the UM......if the switches are ok....the FRONT signals go from them to the buffer amp.....after that they get divided up going to scope and amps.
 
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