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Marantz 2220B problem.

& I checked everything tjis morning while I was at the house...
I spent an hour or more going over it & couldn't find anything wrong.
 
Jermy69 said:
.
& just out of curiosity, why are y'all saying to test those when they don't affect the sound?
I mean, I get what they do...kind of.
But since that's obviously not the issue I was just wondering about that
Click to expand...

These do affect the workings of the unit. You may not "hear" any change necessarily unless they are way off, but those trimmers set what's known as DC offset. Speakers don't work on DC they operate on AC voltage. Those trimmers set the amount of allowable DC going out the speaker terminals and you want as little as possible, ideally 0mVDC,in most cases. When the DC offset is poor, like 50mV or more, it can give an indication of something not operating properly within the unit if you are unable to get the DC offset to match what the service manual says it should be. Check youtube for setting DC offset and you'll get quite a few hits showing how to do it. After working on the unit, you should always reset the DC offset to factory spec and if it won't, you still have work to do. Good luck!
 
Jermy69 said:
That is a good suggestion. But I've already tried that too.
Click to expand...

Clean the component pins with some good cleaner. Make sure you have your soldering iron set to the correct heat, using a good 60/40 solder with flux. Never not had one stick when prepped properly.
 
Jermy69 said:
.
& just out of curiosity, why are y'all saying to test those when they don't affect the sound?
I mean, I get what they do...kind of.
But since that's obviously not the issue I was just wondering about that
Click to expand...
Any time you change components, DC offset and Bias need to be checked and touched up. The new components might change those values. Like I said, if they are not near spec, bad things can happen even if you can't hear a change. It is not about the audio signal. It is about balance in the electrical circuit. You can't hear that. Of course, if it is wildly out of spec, you will hear a difference. But at that point, you are close to damaging something.
 
Steven Tate said:
Any time you change components, DC offset and Bias need to be checked and touched up. The new components might change those values. Like I said, if they are not near spec, bad things can happen even if you can't hear a change. It is not about the audio signal. It is about balance in the electrical circuit. You can't hear that. Of course, if it is wildly out of spec, you will hear a difference. But at that point, you are close to damaging something.
Click to expand...


I gotcha.
I'll look into that. But right now fixing the audio in the left channel is top priority.
 
So I'm thinking if it's not the C705 capacitor and not the connections to it then it must be related to something else.
What did you change just before C705?
 
Magnus Back said:
So I'm thinking if it's not the C705 capacitor and not the connections to it then it must be related to something else.
What did you change just before C705?
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Part of the P300 boars. Only part because I didn't have all the correct caps. I just used what I was sent & the ones I didn't have replacements for are still on the board.

I don't remember if I explained thjs already, but I did a board or two per day & would hook everything back up when I was done...because I use this reciever literally every day.
I just did a few parts at a time on the P700 board though because of how difficult that one is (& I saved it for last.)
 
C705, C706, C709 & c710 were the last parts I had left to do before I was almost completely finished...except for the speaker relay.
 
Hey y'all...
I'll take some pictures tomorrow of the P700 board & post them here.
Is there anything else y'all wanna know that might help?
 
Jermy69 said:
Hey y'all...
I'll take some pictures tomorrow of the P700 board & post them here.
Is there anything else y'all wanna know that might help?
Click to expand...

Which other parts on the P700 board were swapped? We should check those as well. Sometimes issues appear after a while.

To find the issue when there's nothing visual giving us a clue usually involves measuring with the multi-meter to compare the left and right side until we find a difference between the two.
It looks like there are no reference voltage values in the Service Manual for the 2220B so we have to compare.

Does anyone have a circuit diagram for the 2220B P700 board? Would make it much easier ... :-)
 
something happened for sure when you changed that cap . you proved it wasn't the cap itself .something changed . there are variables in play here . without you knowing how the circuits work its going to be some work teaching you all about it and you reading up and studying schematics and learning at least how to use your meter . i suggest you take break for now and study things. not being nasty or nothing we have all had to learn stuff after breaking it . i was lucky and started at an early age
 
Magnus Back said:
Which other parts on the P700 board were swapped? We should check those as well. Sometimes issues appear after a while.

To find the issue when there's nothing visual giving us a clue usually involves measuring with the multi-meter to compare the left and right side until we find a difference between the two.
It looks like there are no reference voltage values in the Service Manual for the 2220B so we have to compare.

Does anyone have a circuit diagram for the 2220B P700 board? Would make it much easier ... :)
Click to expand...

All the capacitors & the two diodes at the top left & top right...or near there.
That's it.
The diodes were changed out after I discovered this problem.
That's all I did to it.

That's all I was given in the kit my girlfriend bought other than the speaker relay & I haven't even tried that yet.
 
petehall347 said:
something happened for sure when you changed that cap . you proved it wasn't the cap itself .something changed . there are variables in play here . without you knowing how the circuits work its going to be some work teaching you all about it and you reading up and studying schematics and learning at least how to use your meter . i suggest you take break for now and study things. not being nasty or nothing we have all had to learn stuff after breaking it . i was lucky and started at an early age
Click to expand...

Problem is I don't know where to begin.
 
Found the circuit diagram, C705 marked.
First measurement could be the input to the transistors H707 and H708. DC voltage should be ~ 28.2V.

p700_C705.jpg
 
Jermy69 said:
Problem is I don't know where to begin.
Click to expand...
the basic health check is checking the settings what you do with those white knobs regardless of the making a difference to you . first check is set your meter to read dc volts and put one probe in in each channels speakers posts as in left plus and minus then in right side . then we can move on to the idle current thing
 
Um...ok...

I'll look into how I can figure it out tomorrow.

Still confused...but I'll try to figure out how to do that
 
If a closer up of any of those is needed, please let me know which one(s) or if there are pictures of anything else I'll be more than happy to get the best picture I can.
 
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