4400 puzzler

Jailtime

Standin' on a corner
I restored my 4400 a while back, worked great as you would expect from a restored receiver. I recently moved, and the 4400 was packed well enough that it wasn't visibly damaged. I put it in my system for the first time since the move, and it's broke. Here's the deal, all inputs sound weak in all channels, volume and balance controls have no effect. So at zero volume, any input sounds like it's just bleeding through.

Power amps are good, I checked them with the main in. Tuner section is good, I used the tape monitor out into another receiver to check that. Power supply voltages are good. I checked around with my scope and a 1KHz signal, there's good signal at the JE01-JE04 inputs to the buffer/preamplifier board. No signal on the JE17-JE20 outputs though. I checked around some of the transistors too, HE13-16 didn't seem to have signal, so I replaced them. Didn't solve the issue though. I should mention the transistors on the board are original.

Start shotgunning transistors? I really should replace the other row of "shithaus" C1345s (HE01-04), but they seemed to be passing signal fine. I'm out of ideas.
 
All four channels have the same issues? That would suggest a power supply supply issue to the preamp board some place. Just seems like something came loose due to the move....cold solder joint.

Being a 4400 owner myself...and knowing all the knobs and switches... wouldn’t be a first for me to have it set up wrong...been there, done that...

I just found a cold solder joint on my 500 after some 6 years later of being in that area of the amp... recently I was get a slow fading out of a channel once the amp warmed up. The joint was likely having issue for some time, but became a real failure after I moved the unit to work on a different area in the amp.

By the way, it was the 4400 and 500 that put the Marantz audio bug in me as a kid in the 70’s, still got that bug. Saw/heard them at a local audio shop as a very young teen and never forgot the first introduction to Marantz to this day.

Jk
 
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I was thinking power supply too, but all the voltages look good on the preamp board. Maybe pinched wire or bad ground?
 
Yup bad ground or pinch wire some place. Seen a few pinched wires show up after transit because the vibration “eats” through the insulation.

An open gorund seems like a good possibility, as it would affect all 4 channels. But it would show up as high voltage on most voltage test points on the preamp board.... I think. Like seeing 35vs almost every where.

I need to clean the 4400 in the living room... you are pushing me to jump in....

Jk
 
Is JE the one with the backwards cap silk screen?
I've had them work for a while with that cap in backwards.

Tom
 
Well, I just learned a big lesson in Keep It Simple, Stupid. Ya know that Local/Remote switch on the back? Yeah, that was in Remote.

4400s, all those knobs and switches. :no:
 
Dude.... here’s me working on my 4400 (not really, I am better looking ;) ).... And your point is what? :D

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Me working on the 4400 scope....
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