nashou
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Tech in Training.....
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Post by nashou on Feb 23, 2014 20:17:19 GMT -5
Ok On to the Pioneer VSX 822-k. On this one I tried the power on test of holding the power button and advanced surround button down and it powered on and shut off. I held it down again for a while with out letting go and got some smoke!!! Uh oh!! I pulled the amp board and thought i may have fried another amp but from that side where the smoke came from the amps are fine. But there is one resistor I sniffed out and it looks burnt and I can not tell the value. its R493 .  Now there is a transistor right behind it not sure if that is bad also. the blown Amps are Q404 and Q410 Q 409 the smaller one in-between them seems of no short. The 100 ohm resistor R439 is also burnt as seen here.  What other parts should I check? Nashou |
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Post by tokejo on Feb 23, 2014 20:28:46 GMT -5
That builds looks exactly like the 1022 that I'm working on. I'm sure Mac will set you straight, but you might be able to take a look at the 1022 thread and x-ref from there.
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Post by mastertech on Feb 23, 2014 20:35:20 GMT -5
Yes, the 822 and 1022 are very similar.
First off you probably should not be trying to force it on so long. If it is shutting down then there is something wrong. The more you force it the more damage can occur.
So first lets look at R493. That is part of the B- supply and when outputs are shorted that is like putting it right to ground. R493 is 33ohm. You will also have to check R551 and Q417 in that circuit.
I will do another post for that FL output.
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Post by mastertech on Feb 23, 2014 20:45:25 GMT -5
Parts to check with shorted outputs. R424 and R425 = 0.47ohm, 1 leg has to be lifted since they are parallel. R430 and R431 = 0.47ohm, "same" D403 ZD403 D404 ZD402 R415 and R439 = 100ohm R443 = 47ohm Q412 Q409 Q408 Q407 Q401 R717 and R438 = 200ohm ZD401 Here is the print if you want to check anything else.   |
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nashou
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Tech in Training.....
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Post by nashou on Feb 23, 2014 21:17:59 GMT -5
Yes, the 822 and 1022 are very similar. First off you probably should not be trying to force it on so long. If it is shutting down then there is something wrong. The more you force it the more damage can occur. So first lets look at R493. That is part of the B- supply and when outputs are shorted that is like putting it right to ground. R493 is 33ohm. You will also have to check R551 and Q417 in that circuit. I will do another post for that FL output. Q 417 I Fried, what is R551 suppose to read? 8 Ohms? I look later at the FL Nashou |
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Post by mastertech on Feb 23, 2014 21:38:06 GMT -5
R551 is 100ohm.  |
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nashou
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Tech in Training.....
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Post by nashou on Feb 23, 2014 22:22:26 GMT -5
Ok then that is bad if I got the right pin. So I measured the parts All diodes fine. One resistor 443 cracked in half when i just touched it!!  So that is bad, 439 is blown 430 and 431 I did not lift but they measured way off compared to all the others of the same type measured the same. i will remove to make sure. R717 and 438 are in parallel so they each measured 98ohms so good. now here is where all hell broke loose Q407,408, and 412 are shorted on some legs. Nashou |
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Post by mastertech on Feb 24, 2014 12:02:58 GMT -5
So do you have a completed list now?
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nashou
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Tech in Training.....
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Post by nashou on Feb 24, 2014 15:34:43 GMT -5
So do you have a completed list now? Almost. MCM electronics has the all the small signal transistors. I think I have most of the resistors, at least I know I have the 100ohm ones Vishay Dales too. Much better. Mouser did not have the KTC transistors but the KSA are really cheap there compared to MCM but not sure i want to pay extra shipping. I would also maybe order a lot of those since I have more Pioneeers here. Unless you have a cross for the one KTC I cant find at mouser. Nashou |
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Post by mastertech on Feb 24, 2014 15:41:46 GMT -5
Which KTC? 3206Y?
Also. where were you getting the 2sd and 2sb from?
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nashou
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Tech in Training.....
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Post by nashou on Feb 24, 2014 16:29:55 GMT -5
Which KTC? 3206Y? Also. where were you getting the 2sd and 2sb from? Both KTC's I cant find at mouser or Digikey. I did not try to cross them tho. The large amps Digikey have and are much cheaper than MCM electronics. But MCM has the KTC's both types. So I think I'll get the KTC;s from MCM i think I have a coupon too from them. I plan to order a bunch of each so I have them in stock incase I need them. I have so many parts building up I could open a repair shop soon!!! If you have a better source let me know. Nashou |
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Post by mastertech on Feb 24, 2014 17:26:40 GMT -5
If Q409 is not blown then audiolabga has all parts.
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nashou
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Tech in Training.....
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Post by nashou on Feb 24, 2014 17:52:08 GMT -5
If Q409 is not blown then audiolabga has all parts. They don't have the KSA's or the KTC3964 :-( |
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Post by mastertech on Feb 24, 2014 18:09:39 GMT -5
KTC3964 is Q409. They do have the KSA's though. If you think you want to order from them I will post the links to the KSA's. Otherwise I won't waste the time.
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Post by mastertech on Feb 24, 2014 18:13:28 GMT -5
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