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Post by youyoudeyou on Feb 15, 2016 7:46:53 GMT -5
My problem:I have a pioneer VSX921K not power on with mcacc blinking(By rls the error using tune- & zone2 off, can power on for 2second then force shut down) My finding: 1. I test AMP transistor ohms resistance no short, no toasted capacitors . 2.I test IC3004 (IC3004 is near the volume control on Front ASSY)pin 80 the voltage show 0.6v and normal it's 5V(manual said it dc error), other protection pin 71/72/81 shows Normal from 4.9 to 5v.(normal is5V). 3.Yesterday I unplugged the power connector marked as "CP401" from AMP board, machine start normally for about five minutes than off. I try to described it as I can because I m not native English speaker and also I m not an expert for the circuit. But I need your kindly advice because I don't know what to do next!Thanks for all of you! Note:The manual From here is not match the actual design of my VSX921k www.hifiengine.com/manual_library/pioneer/vsx-921.shtmlAll the pin and Chip mentioned above is from the manual pioneer VSX1021k(have same design with mine) www.hifiengine.com/manual_library/pioneer/vsx-1021.shtml |
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Post by mastertech on Feb 15, 2016 11:38:12 GMT -5
Well it looks like there are 2 versions of the VSX921k models. The 120v AC version and the 220v AC version and they are totally different in all aspects. So I am assuming yours is the 220v version and yes, would be the same as the 1021.
So now that we have this sorted out let me look over the schematics. I'll be back.
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Post by mastertech on Feb 15, 2016 12:18:30 GMT -5
In there some where is the IR Assy Board (O). Then locate connector CN501. Test for power on any of those lines and let me know. Hopefully you can get to it while assembled. If not, follow that harness back and see if you can test at the other end.
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Post by youyoudeyou on Feb 16, 2016 9:18:32 GMT -5
In there some where is the IR Assy Board (O). Then locate connector CN501. Test for power on any of those lines and let me know. Hopefully you can get to it while assembled. If not, follow that harness back and see if you can test at the other end. I measured all the pin while machine with blinking mcacc light DC-DET4 -0.1mv DC-DET3 -0.3mv ASO-DET -0.1mv RADI-THERMAL 53mv IR-THERMAL 53mv Some thing is wrong with the thermal detection? |
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Post by mastertech on Feb 16, 2016 10:04:51 GMT -5
You have to bring it out of protection when doing the test. If it will not stay on long enough then you have to solder a jumper wire on the main power relay so the unit is powered all the time.
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Post by youyoudeyou on Feb 16, 2016 10:56:34 GMT -5
You have to bring it out of protection when doing the test. If it will not stay on long enough then you have to solder a jumper wire on the main power relay so the unit is powered all the time. Thanks! Mr mastertech! I did it just now and get following readings: DC-DET4 46mv DC-DET3 31mv ASO-DET -1.2mv RADI-TERMAL 53mv IR-THERMAL 51mv While the same time IC3004 pin71 0.66v Pin72 4.0v Pin80 0.41v Pin81 4.86v |
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Post by mastertech on Feb 16, 2016 11:49:42 GMT -5
On that same IR board, remove the harness connected to CN501 and then retest the pins on ic3004.
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Post by youyoudeyou on Feb 17, 2016 9:14:17 GMT -5
On that same IR board, remove the harness connected to CN501 and then retest the pins on ic3004. While disconnect CN501, the reading are as follow: pin71 0.78v Pin72 81mv Pin80 0.51v Pin81 80mv The reading is normal for pin 71 &80? Thanks and appreciate for you quick response every time! |
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Post by mastertech on Feb 17, 2016 10:14:45 GMT -5
Did you bring it out of protect to do that last test?
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Post by youyoudeyou on Feb 17, 2016 10:29:04 GMT -5
Did you bring it out of protect to do that last test? While disconnect CN501 and with jumper main power relay,machine still just power on for 5second than off, then HDMI light blinking instead of mcacc. Is there some button to power on the machine at this moment? |
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Post by mastertech on Feb 17, 2016 13:05:20 GMT -5
I will assume you have the relay properly jumped.
Put CN501 harness back in.
Remove these transistors from the IR board and then retest your voltages on the ic and see if they have come up. (Q527,Q530,Q533)
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Post by youyoudeyou on Feb 18, 2016 11:33:01 GMT -5
I will assume you have the relay properly jumped. Put CN501 harness back in. Remove these transistors from the IR board and then retest your voltages on the ic and see if they have come up. (Q527,Q530,Q533) Remove Q530 527 533 pin71 4.86v Pin72 4.11v Pin80 0.42v Pin81 5.02v POWER ON than still get mcacc light blinking !Then I need to remove more transistor on IR board related pin 80? |
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Post by youyoudeyou on Feb 18, 2016 11:45:06 GMT -5
I will assume you have the relay properly jumped. Put CN501 harness back in. Remove these transistors from the IR board and then retest your voltages on the ic and see if they have come up. (Q527,Q530,Q533)  I just found that there was no Q528 Q525 exist on IR board for VSX921k,so that's the reason why no high voltage on pin80 even I removed Q527 Q530? What should I do next, I think I m getting so close to the truth within your step by step guiding.！ |
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Post by mastertech on Feb 18, 2016 11:50:06 GMT -5
remove Q526 and Q529 and retest.
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Post by youyoudeyou on Feb 18, 2016 12:24:36 GMT -5
remove Q526 and Q529 and retest. after removed them, unit power on normally then off after about15 seconds with out any lights blinking, only unplug the main power then can power on again and do the same thing. The 4pins all reads 0v during it powered on! |
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