Pioneer Reverb SR-303 Not Powering On.

[ajohnnyz]

Every single time I turn the amp off and back on it works perfect for 10 minutes. And then it starts to fail at 10 minutes. There's no components inside the balance control so why would it work right and then be affected after 10 minutes? I appreciate your opinion but I don't think there's anything wrong with balance pot itself. I tend to think this is a problem with something I did on the other board or something went bad on this board because of what I did on the other board.

 

[dr*audio]

so why would it work For 10 minutes every single time and then fail.

I can't explain that, but it measures bad. The readings on B and E are barely changing. E changes only at the extreme and not enough.

 

[ajohnnyz]

I can't explain that, but it measures bad. The readings on B and E are barely changing. E changes only at the extreme and not enough.

Well obviously, it would be nearly impossible for me to get another balance control for this. Are you sure there's absolutely no other component on the board that would be causing this issue?

 

[ajohnnyz]

I'll call my Fix It guy tomorrow and schedule a drop off for him to fix it, Unfortunately it will probably be $350. And after that I'll let you know what he comes up with.

 

[dr*audio]

I'll call my Fix It guy tomorrow and schedule a drop off for him to fix it, Unfortunately it will probably be $350. And after that I'll let you know what he comes up with.

In my opinion, it's a waste of money. You don't need the balance control. How often do you use it? As long as you don't have one speaker in a corner and the other in the middle of a wall you don't need a balance control.

 

[ajohnnyz]

In my opinion, it's a waste of money. You don't need the balance control. How often do you use it? As long as you don't have one speaker in a corner and the other in the middle of a wall you don't need a balance control.

But the problem is it's affecting the sound, It merges both channels into one channel There's no more left and right.

 

[dr*audio]

I didn't notice that in your description of the problem. On that balance control, with the balance in the center, measure the resistance from B to E.

 

[ajohnnyz]

I didn't notice that in your description of the problem. On that balance control, with the balance in the center, measure the resistance from B to E.

73.1K And remember the SPEC 1 is not plugged in or powered on. The issue doesn't occur until after it's been on for about 10 minutes. I can turn it off and turn it back on and it all works fine again for about 10 minutes it resets very quickly just turning it off and turning it on.

 

[dr*audio]

73.1K And remember the SPEC 1 is not plugged in or powered on. The issue doesn't occur until after it's been on for about 10 minutes. I can turn it off and turn it back on and it all works fine again for about 10 minutes it resets very quickly just turning it off and turning it on.

Ok, just wanted to see if the 2 channels are shorted together. They may be shorted elsewhere but not at the balance control. I don't have an explanation for the time delay. This is the type of problem you have to input a signal only on one channel and go through it with a scope to see where it becomes mono.

 

[ajohnnyz]

I ordered a small AMP that should be in today. That way I won't have to carry the 70 pound amp up and down the stairs be able to set something up on the bench to start trying to figure this out. Plus, if I have the same problem with the new small amp it will rule the SPEC 2 having anything to do with the issue.

 

[ajohnnyz]

At this point I don't know what to do or where to start testing on how to figure this out and fix it?

 

[dr*audio]

At this point I don't know what to do or where to start testing on how to figure this out and fix it?

This is the type of problem you have to input a signal only on one channel and go through it with a scope to see where it becomes mono.

 

[ajohnnyz]

This is the type of problem you have to input a signal only on one channel and go through it with a scope to see where it becomes mono.

OK i'm there.... Just where to test and how to test and I will do it. If I knew how to do everything I wouldn't be on this forum. Like I said I dealt with a guy years ago I had no issues he walked me through everything sent pictures I was good I was able to figure everything out do what he asked and then I got referenced all the parts I should buy and I changed out all the parts went very smoothly.

So again with that said I changed a bunch of parts on the 82 Bored and I don't know if that board flows through this board and there could have been a problem with what I changed out that reflects on the 83 board? I keep trying to provide all the information I can possibly provide.

 

[sregor]

Tip. Run one channel in at a time, and trace signal when malfunctioning.

 

[dr*audio]

1. Set your audio generator at 1KHz sine wave 440mV.
2. Connect generator to left Aux input on preamp. Set balance control to the middle.
3. Turn on preamp, set to Aux input, turn volume to at least 1/4. You don't have to connect an amp to the output.
4. Monitor both output channels with the scope. Let it run until you see an output on both channels.
5. connect scope to the center pins on the balance control. Do you see signal on both channels? (each center pin of the control is one channel.)

 

[ajohnnyz]

1. Set your audio generator at 1KHz sine wave 440mV.
2. Connect generator to left Aux input on preamp. Set balance control to the middle.
3. Turn on preamp, set to Aux input, turn volume to at least 1/4. You don't have to connect an amp to the output.
4. Monitor both output channels with the scope. Let it run until you see an output on both channels.
5. connect scope to the center pins on the balance control. Do you see signal on both channels? (each center pin of the control is one channel.)

OK I got it all set up and The balance is working 100 percent correctly. I do see a signal on the balance center pins for each channel. I am going to let it run for a while and see if anything changes. Will let you know.

 

[ajohnnyz]

1. Set your audio generator at 1KHz sine wave 440mV.
2. Connect generator to left Aux input on preamp. Set balance control to the middle.
3. Turn on preamp, set to Aux input, turn volume to at least 1/4. You don't have to connect an amp to the output.
4. Monitor both output channels with the scope. Let it run until you see an output on both channels.
5. connect scope to the center pins on the balance control. Do you see signal on both channels? (each center pin of the control is one channel.)

OK its been running over 2 hours now and the balance is still working perfectly on the output channels, and still separated on center balance pins, it's all working perfectly. So now what?

 

[dr*audio]

OK its been running over 2 hours now and the balance is still working perfectly on the output channels, and still separated on center balance pins, it's all working perfectly. So now what?

Well, just to make sure, run it awhile longer and turn it off and on a few times. If it's an intermittent problem that's about all you can do.
Question:
The last time it messed up for you what did you have connected to it; the amp and what else? A tape deck?

 

[ajohnnyz]

Well, just to make sure, run it awhile longer and turn it off and on a few times. If it's an intermittent problem that's about all you can do.
Question:
The last time it messed up for you what did you have connected to it; the amp and what else? A tape deck?

Ok, of and on and another 3 hours and no issues with the balance. When hooked up to the AMP it was using the CD player through Aux 1, so all the same as now minus the AMP.

 

[dr*audio]

Ok, of and on and another 3 hours and no issues with the balance. When hooked up to the AMP it was using the CD player through Aux 1, so all the same as now minus the AMP.

Hmm, that means that either you have an intermittent problem in the preamp or the problem is in the amp. I guess try another preamp with the amp and see what happens.