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Pioneer Reverb SR-303 Not Powering On.
- Thread starter ajohnnyz
- Start date
Sounds like a bad ground on the balance control. A cap somewhere may be providing a ground until it charges up.
ajohnnyz
Active Member
Not sure, it takes anywhere from 1 - 3 hours for it to start doing that.
ajohnnyz
Active Member
No the spec 2 works fine as far as I know, I just got that back from Service. When I Turn individual knobs on the spec 2, turn top knob, the right channel goes quiet, bottom knob is the left channel goes quiet.
The problem is with the balance knob on the spec one. Turning it left or right doesn't do anything after an hour or three. I get this one is so weird it's gonna be super hard to troubleshoot because it not constant. Well it is constant once it happens it stays that way until I turn it off turn it back on.
ajohnnyz
Active Member
So let me explain clearly if I can. I turned the stereo on this morning The balance on spec 1 the preamp works perfectly I turn the knob to the left The left channel plays I turn the knob to the right Only the right channel plays all is good. About halfway through a CD I turned the balance knob on the spec one preamp to the left and nothing happens, It continues to play on both speakers, I turn it to the right and nothing happens it continues to play on both speakers.
You have a bad ground on the balance control. Measure the resistance between the power supply ground and the chassis and from the chassis to the balance control. If there are shielded cables on the control, the shield is ground. You probably have a broken wire somewhere.
ajohnnyz
Active Member
Thank you, I'm working two jobs and I have kids so I will get to this one of these days.
ajohnnyz
Active Member
And a list of some of the components that I've changed in the SPEC 1. Has to give you some history Not sure of anything there would affect the balance
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ajohnnyz
Active Member
OK, it takes me a while to get that rack moved out, disconnect everything, and bring the unit down to my bench.
Once I had it on the bench and removed the top cover, the first thing I noticed was that C69 on the AWG-035 board was disconnected — see picture. I’ll fix that, but before I go any further I’m wondering if you think that alone could have been the issue? But I'm guessing that would have maybe caused a treble issue.
To properly test it, I would need to move the amp down and hook everything up again.
Right now I’m using my waveform generator into AUX 1, and I connect the oscilloscope to Record Out. I can see the signal on both the left and right channels, but the balance control doesn’t affect the Record Out, so that test doesn’t really tell me if the issue is fixed.
Because of that, I’m guessing I would still have to pull the SPEC-2 out of the rack and bring it down to the bench for proper testing.
That’s the frustrating part — the thing weighs about 70 pounds, and moving everything in and out of the rack and up and down the stairs is honestly a nightmare.
Once I had it on the bench and removed the top cover, the first thing I noticed was that C69 on the AWG-035 board was disconnected — see picture. I’ll fix that, but before I go any further I’m wondering if you think that alone could have been the issue? But I'm guessing that would have maybe caused a treble issue.
To properly test it, I would need to move the amp down and hook everything up again.
Right now I’m using my waveform generator into AUX 1, and I connect the oscilloscope to Record Out. I can see the signal on both the left and right channels, but the balance control doesn’t affect the Record Out, so that test doesn’t really tell me if the issue is fixed.
Because of that, I’m guessing I would still have to pull the SPEC-2 out of the rack and bring it down to the bench for proper testing.
That’s the frustrating part — the thing weighs about 70 pounds, and moving everything in and out of the rack and up and down the stairs is honestly a nightmare.
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ajohnnyz
Active Member
SPEC 1 bottom.
On first inspection of the bottom, I don't see loose wires, anything disconnected, or any touching.
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That picture is not high enough resolution to see anything if you zoom in.
Measure the resistance between power supply ground and the chassis. If that is good (less than 1 Ohm) start measuring from the chassis to ground on the balance pot, and every place on the filter board that is supposed to be ground.
ajohnnyz
Active Member
Ok, and FYI Here's the with no power on the spec one it's not even plugged in, Waveform generator hooked to the Aux 1 and scope record out, And this is good and I let it run for a while and the purple line goes away. I shake the entire spec one and it comes back So yeah something is loose somewhere. I tap on everything and move everything around and it doesn't change anything so it's internal somewhere I'll have to dig into it more.
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ajohnnyz
Active Member
OK so I deoxed everything again and shook the heck out of it several times. I tighten all the screws I could see, and for 4 hours the scope has been solid. I picked the thing up and shake the heck out of it and it holds solid. So I'm gonna let it run for another day and see if it holds solid on the scope and then try it out. I just don't wanna take it all apart if I shook loose whatever the issue was? I just learned from experience messing with things that don't need messing with can cause more problems. We will see.
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I gave you the troubleshooting method, to measure the resistance of the grounds. You didn't do it. Maybe you'll get lucky but since you didn't do any testing you won't know for sure.
ajohnnyz
Active Member
Oh I know and I'm keeping all that in mind but I really don't wanna have to take the entire thing all apart and pull the boards off to do all that if I don't have to I hope you understand.
I would have to pull all the knobs off the front take the front off unscrew everything Pull the boards out cut all the zip ties Flip the boards up There's a lot involved to do that I'm just trying to avoid doing all that at this point if I shook something loose. I have all your instructions to move forward I'm just going to wait it out and see if I shook something loose and it's all good without tearing a thing apart. I shipped this thing before and every time the scope went crazy and now it's been rock solid no matter what I do to it so I don't know what happened and maybe I shook something loose. Again I have all your instructions to move forward... And I appreciate it very much i'm not disregarding any of that. But again I've never had any issues with this so I'm hoping there was just Something weird going on and it got shook loose? We will see scope is still rock solid and I'm throwing that thing all around the bench and shaking it dropping it and the scope is rock solid.
I have it powered on now just to see if letting everything warms up changes anything. We will see and I will keep you posted.
I mean the scope changed every few minutes before and it's been rock solid so I don't know?
And to be honest I honestly don't know where all the grounds are and how to do everything you told me to do. Sorry I'm a pretty smart guy and I can do a lot of things but I'm here on the farms because I don't know how to do any of this. I need 100% hand holding point A to point B test here and test there That's the only way I would be able to do anything at this point It's all new to me and I don't get any of it.
I don't know the scope's been solid all day Maybe I shook something loose? I'm gonna go put it back in the rack and hook it up and see what we have? If we have a problem I will move forward with everything you suggested.
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