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Post by nonoise on Sept 10, 2017 11:29:27 GMT -5
Hi all,
Bought myself an oldskool beast.
The Poa 2200, now the problem is that there is no sound, but there is power.
3/4 of the front LEDs are blinking,when I hit the protect button the error resets. But after a few seconds it returns to 3/4.
So my best guess is to solder all the connections again.
Maybe someone got any idea?
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Post by mastertech on Sept 10, 2017 14:33:09 GMT -5
Check solder joints. I that does not fix it I have the schematics so we can troubleshoot.
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Post by nonoise on Sept 15, 2017 18:08:10 GMT -5
Resoldered all solder joints. Still the same error. Cleaned the prints with alcohol.
DC offset was - 7,2 and - 8,4
I have a fluke multimeter and a scope at my disposal.
If my thoughts are correct it must be the right channel, because it's barely getting warm. And the left channel is getting warm.
Hope you can help
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Post by mastertech on Sept 16, 2017 9:11:09 GMT -5
Test DC voltage across caps: C587,C588,C589,C590
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Post by nonoise on Sept 16, 2017 10:51:20 GMT -5
In circuit?
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Post by nonoise on Sept 16, 2017 12:02:50 GMT -5
Measured them in circuit.
C587 72,5
C588 72,9
C589 72,1
C590 73,1
Accidently short circuited the c590. Measured it afterwards gives me the same value.
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Post by mastertech on Sept 16, 2017 13:42:03 GMT -5
Unless I say otherwise all measurements are in circuit. Besides, you cannot measure voltage out of circuit.
Now measure DC voltage across C592 and C591.
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Post by nonoise on Sept 16, 2017 14:11:17 GMT -5
Unless I say otherwise all measurements are in circuit. Besides, you cannot measure voltage out of circuit. Now measure DC voltage across C592 and C591. Yes I figured that out later haha. C592 59v C591 0,007 |
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Post by mastertech on Sept 16, 2017 14:24:52 GMT -5
Looks like your right channel is blown. Do you know how to go from here?
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Post by nonoise on Sept 16, 2017 14:54:23 GMT -5
Not really. My best guess is desolder the transistors and test them.
But when I found the broken one or ones I need to measure further in the circuit to find more broken components?
Could use the the help.
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Post by mastertech on Sept 16, 2017 18:05:53 GMT -5
I would remove TR532,TR534,TR536,TR538 and do a diode test on each one checking for shorted legs. If I found shorted legs I would then check for voltage across C592 again, leaving those transistors out.
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Post by nonoise on Sept 17, 2017 7:05:47 GMT -5
Tr538 0,555 and 0,557
Tr536 0,564 and 0,565
Tr532 gave me good values then nothing then good values, now nothing.
Tr534 first nothing then good values now nothing.
So the 532 and 534 are dead. Didn't knew they could give good results. Are the broken ones the input transistors?
C592 gave me something close to 0,007. And it also gave me 54. Testing it a few times :0,007.
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Post by mastertech on Sept 17, 2017 13:10:34 GMT -5
Does the unit come out of protect and stay out now?
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Post by nonoise on Sept 17, 2017 15:10:50 GMT -5
C602 blew r550 r548 r542 started to melt.
I tested it first with no problem.
Someone moved it, so it short circuited there. Don't want to turn it on.
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Post by nonoise on Sept 17, 2017 15:20:08 GMT -5
D516 short circuited with j607. That made the cap blew. Stupid...
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