RX-5350 issue...

So I bought this Panasonic from ebay knowing it had an issue. The guy I got it from told me about it and said it did a weird thing when it hadn't been turned on for a while.




The first time I turned it on the speakers would fully extend and retract making a wub sound about once every 2 seconds. They started at slightly different frequencies with the left a bit slower than the right and both gradually sped up until it became a constant noise and then stopped after about 5 minutes. The right speaker finishing a minute or so before the left. You could play music while this was going on but it was very distorted. After that it distorted a little initially but then became fine on line in or radio, just the tape player distorts a bit. I left it off for a few weeks hoping it would do it again and I could video it and post it here but I turned it on again today and it worked fine.

Does that make sense? Anyone seen that before?

Excessive DC at the outputs = very bad, especially for speakers
Oscillation in the circuits
Suggest a huge recapping is in order....

Ahh, I was bidding on that too....

I was almost sure it was the rec bar because the same thing happened on my 767 before I sprayed the rec bar......

Very possible Max. I presume however that the simple cleanings, etc, was already performed before asking for help. Another thing to look into is transistor bias adjustments. Also ground loop issues.

Sean, if you want me to check it out like we talked about a while ago, I'm happy to do that for you
I am planning on been down your way in a week or two.

tshorba said:

Sean, if you want me to check it out like we talked about a while ago, I'm happy to do that for you
I am planning on been down your way in a week or two.

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Yeah man, that sounds awesome

Sazeus said:

So I bought this Panasonic from ebay knowing it had an issue. The guy I got it from told me about it and said it did a weird thing when it hadn't been turned on for a while.


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The first time I turned it on the speakers would fully extend and retract making a wub sound about once every 2 seconds. They started at slightly different frequencies with the left a bit slower than the right and both gradually sped up until it became a constant noise and then stopped after about 5 minutes. The right speaker finishing a minute or so before the left. You could play music while this was going on but it was very distorted. After that it distorted a little initially but then became fine on line in or radio, just the tape player distorts a bit. I left it off for a few weeks hoping it would do it again and I could video it and post it here but I turned it on again today and it worked fine.

Does that make sense? Anyone seen that before?

Click to expand...

I'm agreeing with superduper on the cap replacement. Does that model take batteries? Does it have the same symptoms w/batteries? Can't believe you left it on for 5 minutes though those poor speakers.

Superduper said:

Very possible Max. I presume however that the simple cleanings, etc, was already performed before asking for help. Another thing to look into is transistor bias adjustments. Also ground loop issues.

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Simple cleanings for some are a little more of an endeavour for those of us with little to no technical experience. I managed to get a squirt of deoxit in there but the rec bar is tricky to get at without taking the tuner/bunch of circuitry off. I'll wait for Matt to come along with his electronics wizardry before we go any further I think. Thanks for the ideas.

I said about the cleaning because truth be told, a simple cleaning resolves so much problems that how can we possibly focus on issues that aren't resolved by cleanings if we don't first remove that cloud. If someone is unable to conduct something as simple as deoxit of the controls and record bar, then really what is the point of asking for help, because that will indeed be the first thing to be recommended. The simplest and easiest solution for any electronics malady is deoxit and every person here would be hoping and praying when they have a problem, that it would be resolved by that one maintenance process. Therefore, if a cleaning does not resolve it, then any other solution will only increase in the degree of difficulty by many orders of degree.

Agree?

All the best with sorting it out Sean. Cleaning of controls first is def the way to go. After that if problems still persist then Superduper is the man with the knowledge. He diagnosed my big ben's illness while being half a world away.

Scotty

Superduper said:

I said about the cleaning because truth be told, a simple cleaning resolves so much problems that how can we possibly focus on issues that aren't resolved by cleanings if we don't first remove that cloud. If someone is unable to conduct something as simple as deoxit of the controls and record bar, then really what is the point of asking for help, because that will indeed be the first thing to be recommended. The simplest and easiest solution for any electronics malady is deoxit and every person here would be hoping and praying when they have a problem, that it would be resolved by that one maintenance process. Therefore, if a cleaning does not resolve it, then any other solution will only increase in the degree of difficulty by many orders of degree.

Agree?

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Yeah man, I'm with you on that. That being said, if the box has done this thing only once in the 6 weeks I've owned it and the only symptom it's now showing is the slightly muffled tape, is it important to test for those other possible problems or just roll with it until it shows another symptom?

now controls have been cleaned of course

After an afternoon of re-capping she is back to her former glory. It has made a world of difference in sound quality. Thanks to Will and his steady soldering hand.

That is good news!

Did you replace all the polyester capacitors in it?

So satisfying to see it sounding so good!

Did you order those amps yet haha?

Sazeus said:

After an afternoon of re-capping she is back to her former glory. It has made a world of difference in sound quality. Thanks to Will and his steady soldering hand.

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As I suspected. Glad it's all working. I bet it sounds better than before? Although with so much time passing between when it last worked, it's probably hard to tell before/after.

That's great new, congrats on the fix!

BoomboxLover48 said:

That is good news!

Did you replace all the polyester capacitors in it?

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I don't think so, just electrolytic ones I'm told.

Superduper said:

As I suspected. Glad it's all working. I bet it sounds better than before? Although with so much time passing between when it last worked, it's probably hard to tell before/after.

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Oh it was working before, just distorting somewhat. It was only the first time I turned it on that it went crazy. So much better now.