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Marantz 2216 recap

Controls have been cleaned. The amp worked fine before starting the recap. I recapped the power supply and then it started. Though the voltages are fine on the power supply which is weird, I still think something went wrong with the power supply. Maybe the transistor?
 
Voltages are good on the transistor bro, all voltages coming out of the power supply are good. Do you own a scope?
 
How about the tape monitor button. Push it in and out a few times and see if any change.
 
The balance slider works only to one side, it was like that when I bought it and the amp worked fine nonetheless. I have played with it a little to check whether it makes any difference, it doesnt. Tried the tape monitor also: no difference.

Isn't it key to this riddle that the amp works fine for the first 4 seconds, then something goes wrong and bam, distortion appears?
 
You need to determine "where" it is distorting- that's the challenge, pre amp or amp and that unit doesn't allow you to separate the amp from the pre.
 
On the power supply board there are several pins which connect the board to the circuit, J801-815. Check the wires and make sure none of them are loose. Perhaps you have a bad connection.

BK is right on, you would need to start tracing the signal path to see where the distortion begins. It is much more difficult without a scope of course. There is an area you could separate the preamp from the amp. See pins J701 and J702 on the amp board, those are your left and right signals sharing J703 common ground coming from the preamp and going to the amp. This is where you could tap to add a set of jumpers on the back of the amp.

In any case, I'm still not sold this is a preamp or amp issue. Since it is both channels and happened after the recap of the power supply the problem probably lies there. Check the voltages again at the PS board then follow the wires to the board it feeds and check it there. Perhaps you have a bad wire or one of you wire wraps have failed. I have had wires detach at the wire wrap from manipulating the board to gain access to the trace side.
 
HVHiFI said:
On the power supply board there are several pins which connect the board to the circuit, J801-815. Check the wires and make sure none of them are loose. Perhaps you have a bad connection.

Perhaps you have a bad wire or one of you wire wraps have failed. I have had wires detach at the wire wrap from manipulating the board to gain access to the trace side.
Click to expand...

2nd that. I had a receiver that exhibited the same symptoms and turned out it was a loose wire on the tone board. A wire had broken off at the wrap junction. They're a b&*$h to get back on - you need to really clean the post to get the solder to stick. Check all of those wraps. If you had any boards bent back for soldering, a wire could be loose.
 
Will definiterly check the voltages at destination. My gut also tells me that it is the power supply board. Will check tonight and let you know. Thanks!
 
I checked the voltages at destination and the wires and everything was perfect. So I decided to carry on and start recapping the tone board. I had only time to change one cap so I decided to replace the 100uf/50v cap which looked REALLY bad and guess what, the volume is back and the distortion is not completely gone but almost. A full recap of the tone board will probably do the trick. As someone mentioned before, recapping the power supply probably caused some of the tone board caps (and maybe somewhere else) to completely fail. The cap I replaced was completely blown and leaking. I will keep you posted.
 
Sounds like your tracking it down. May want to check the transistors downwind of that cap that failed.
 
So finished recapping the tone board.The tone board was not original, somebody had replaced some of the caps with different values than the manual stated. I know they where not original as the solder traces where obvious. Anyways, after recapping I tested and it sounded sweet.

So I gave him a little bit of volume and he blew away the 100uf 50v cap. :( It turns out I had placed it backwards. \

I replaced the blown cap with another one soldering it correctly and guess what: the distortion is back! the same old distortion...


How can it be that with that cap backwards (though it blew away), the amp sounded great... with the cap properly installed it sounds horrible.

Could this be the transistors? Im testing them with the DVM and I get weird readings...

What are good replacements for: 2SC1328 T and 2SA722 S?

Thanks!
 
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Are the following appropriate replacements:

512-KSA992 for the 2SA722
512-KSC1845 for the 2SC1328

Thanks
 
So, an update. I replaced all transistors on the Tone Board. The distortion has been noticeably reduced but it is still there. Which means that the replacement of the transistors had a positive effect but there is still something wrong going on.

There is only resistors and film caps left original on the tone board. Can any of these be causing the problem?

Could this be transistors on the Main Amp Board?

Im close to admitting defeat to this one... at least until I buy a scope (and learn how to use it)

Any help would be extremely appreciated.
 
It distorts with the radio and aux, Have not tried phono.... and to make clear what the distortion is: now its a small reduction in volume accompanied by what sounds like "bad reception" or robotic like sound. With the old transistors the volume reduction was huge, now its only a little bit. And it remains that when I turn off the power (or on with source playing) it sounds ok for a couple of seconds and then the distortion kicks in.
 
Without a scope all you can do is take voltage measurements- if you're confident it's not in the pre measure voltages on the amp compared to the schematic.
 
Im pretty much confident that the problem is still the pre but how do I test it further? I could test transistor voltage, if not correct, given that the trannys are brand new, I can trace back the problem to the right component... right?
 
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