Sansui 9090 speakers pop

You want me to adjust them now?

Sure. Just be careful when connecting your probes to the speaker terminals. Best to turn the speaker selector to OFF, connect the probes, turn selector to ON, do the adjustment, then turn it back to OFF, move the probes, then back to ON and adjust that channel. This avoids the risk of shorting terminals with probes.

And again...MAKE SURE YOU ARE ADJUSTING THE CORRECT POTS!!:)

See if you can get both channels close to zero (+/- 25mV is fine).
 
Sure. Just be careful when connecting your probes to the speaker terminals. Best to turn the speaker selector to OFF, connect the probes, turn selector to ON, do the adjustment, then turn it back to OFF, move the probes, then back to ON and adjust that channel. This avoids the risk of shorting terminals with probes.

And again...MAKE SURE YOU ARE ADJUSTING THE CORRECT POTS!!:)

See if you can get both channels close to zero (+/- 25mV is fine).
Ok i just drop both to under 10
 
Good.

Now, with the amp turned off, connect your speakers.

Next, with the speaker selector to OFF, turn on the amp.

Wait until you hear the relay, then turn on the speakers. Any POP?

Turn it off...any POP? One or both channels?

Let it sit for a few minutes, then turn it on again (this time, with speaker selector ON). Did it POP this time? If so, is it coming from one channel or both?

We are making progress.
 
Good.

Now, with the amp turned off, connect your speakers.

Next, with the speaker selector to OFF, turn on the amp.

Wait until you hear the relay, then turn on the speakers. Any POP?

Turn it off...any POP? One or both channels?

Let it sit for a few minutes, then turn it on again (this time, with speaker selector ON). Did it POP this time? If so, is it coming from one channel or both?

We are making progress.
The first time I power it up with speaker off the open, no pop, BUT no more sound on speaker right in stereo but yes on mono. Waiting a bit now to re power the amp
 
Which pots did you adjust?

OK, let's make sure I understand the current situation:

  • You still get the pop when you turn on the amp. Correct?
  • Does the pop occur in both channels or just on one?
  • Does the pop occur before or after you hear the relay click?
  • Are both speakers working? Does the music sound distorted or have noise in it?
Please answer each question.

FYI, I did not expect that adjusting the DC offset would fix the pop. I just wanted to find out if you could adjust it down to a reasonable level.

So far, I suspect a problem with your protection relay...possibly caused when you caused a short or arc at the fuse holder.
 
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Which pots did you adjust?

OK, let's make sure I understand the current situation:

  • You still get the pop when you turn on the amp. Correct?
  • Does the pop occur in both channels or just on one?
  • Does the pop occur before or after you hear the relay click?
  • Are both speakers working? Does the music sound distorted or have noise in it?
Please answer each question.

FYI, I did not expect that adjusting the DC offset would fix the pop. I just wanted to find out if you could adjust it down to a reasonable level.

So far, I suspect a problem with your protection relay...possibly caused when you caused a short or arc at the fuse holder.
I still get the pop, only on the left channel as soon as I push the power button, music in both and sounding good
 
Given everything we know so far, I suspect the left channel relay is closed. Personally, I would just replace it...but you can try to open it up (pop off the plastic cover) and see if you can work a strip of very, very fine sandpaper (1200 grit or higher) between the contact points. Or, just try a strip of notecard or typing paper soaked in deoxit. The coating on these points is VERY thin, so only one or two passes.

If a contact point is indeed stuck in the closed position, replacing the relay is a much better idea, but cleaning the points may work (assuming they are not fused from your earlier misadventures).

Here is a thread about getting the cover off:

http://www.audiokarma.org/forums/index.php?threads/relay-cover-shucker.19413/

If you replace the relay, I would recommend replacing all the electrolytics on that board while you are at it. I seem to remember that one or two of them are bipolar, but they are not indicated as such on the parts list in the service manual. So check the values you need by looking at the actual caps on the board before ordering.
 
Given everything we know so far, I suspect the left channel relay is closed. Personally, I would just replace it...but you can try to open it up (pop off the plastic cover) and see if you can work a strip of very, very fine sandpaper (1200 grit or higher) between the contact points. Or, just try a strip of notecard or typing paper soaked in deoxit. The coating on these points is VERY thin, so only one or two passes.

If a contact point is indeed stuck in the closed position, replacing the relay is a much better idea, but cleaning the points may work (assuming they are not fused from your earlier misadventures).

Here is a thread about getting the cover off:

http://www.audiokarma.org/forums/index.php?threads/relay-cover-shucker.19413/

If you replace the relay, I would recommend replacing all the electrolytics on that board while you are at it. I seem to remember that one or two of them are bipolar, but they are not indicated as such on the parts list in the service manual. So check the values you need by looking at the actual caps on the board before ordering.

And get rid of those fusible resistors (just use good metal films) and VD1212 diodes on the driver board while you are at it. But only undertake any of this work if you are confident in your ability to do it correctly!
 
Given everything we know so far, I suspect the left channel relay is closed. Personally, I would just replace it...but you can try to open it up (pop off the plastic cover) and see if you can work a strip of very, very fine sandpaper (1200 grit or higher) between the contact points. Or, just try a strip of notecard or typing paper soaked in deoxit. The coating on these points is VERY thin, so only one or two passes.

If a contact point is indeed stuck in the closed position, replacing the relay is a much better idea, but cleaning the points may work (assuming they are not fused from your earlier misadventures).

Here is a thread about getting the cover off:

http://www.audiokarma.org/forums/index.php?threads/relay-cover-shucker.19413/

If you replace the relay, I would recommend replacing all the electrolytics on that board while you are at it. I seem to remember that one or two of them are bipolar, but they are not indicated as such on the parts list in the service manual. So check the values you need by looking at the actual caps on the board before ordering.
All right!! Thanks a lot for your help. I’ll go with a new one, seems the better idea
 
You can run the amp as is, but realize that you don't have protection on the left channel...so you are taking a risk. If you decide to take this risk, turn your speakers OFF before your turn the amp on or off.

Before you order a new relay and the other parts I mentioned, you really should verify that a stuck contact is the problem. You can get at that board from the side of the chassis. It's a bit difficult to get out...work carefully so as to avoid stressing the wired connections.

And again....undertake this work ONLY if you are confident in your ability to do it correctly. The 9090 is a very nice amp...you don't want to cause more problems.
 
You can run the amp as is, but realize that you don't have protection on the left channel...so you are taking a risk. If you decide to take this risk, turn your speakers OFF before your turn the amp on or off.

Before you order a new relay and the other parts I mentioned, you really should verify that a stuck contact is the problem. You can get at that board from the side of the chassis. It's a bit difficult to get out...work carefully so as to avoid stressing the wired connections.

And again....undertake this work ONLY if you are confident in your ability to do it correctly. The 9090 is a very nice amp...you don't want to cause more problems.
:trebon:
 
I would appreciate it if you report back on your findings. Take care, and good luck with it.
 
I would appreciate it if you report back on your findings. Take care, and good luck with it.
Sorry for the long delay, I said I would get back to you. I did change the relay and mostly all the caps along the way and everything is back to normal.
Thanks spark1
 
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