Pioneer VSX-921k power on fail with MCACC blinking

mastertech Global Moderator Posts: 3,538	Pioneer VSX-921k power on fail with MCACC blinking Feb 18, 2016 12:54:27 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by mastertech on Feb 18, 2016 12:54:27 GMT -5 The 4 pins on the ic read 0v while it is powered up? That does not make sense.
	MT

youyoudeyou
New Member

Posts: 17

Pioneer VSX-921k power on fail with MCACC blinking Feb 19, 2016 10:30:34 GMT -5 via Tapatalk

Quote

Post by youyoudeyou on Feb 19, 2016 10:30:34 GMT -5

Feb 18, 2016 12:54:27 GMT -5 mastertech said:

The 4 pins on the ic read 0v while it is powered up? That does not make sense.

Yes, you are right! I just retest the 4pin on ic3004 during the short moment the unit is on, voltage is just around 4.8 to 5v .
Now the unit turn itself off just no more than 15seconds. Some thing still wrong with the main board itself?

mastertech
Global Moderator

Posts: 3,538

Pioneer VSX-921k power on fail with MCACC blinking Feb 19, 2016 11:18:33 GMT -5

Quote

Post by mastertech on Feb 19, 2016 11:18:33 GMT -5

Ok. Here is what you need to do.
First, test Q533 that you removed with your DMM on diode scale and make sure it is good.
If good, then reinstall it. Just that one, not any of the others.
Then retest pins on ic3004 and see if any voltages have dropped.

youyoudeyou
New Member

Posts: 17

Pioneer VSX-921k power on fail with MCACC blinking Feb 21, 2016 10:52:22 GMT -5 via Tapatalk

Quote

Post by youyoudeyou on Feb 21, 2016 10:52:22 GMT -5

Feb 19, 2016 11:18:33 GMT -5 mastertech said:

Sorry I didn't have time to do the testing yesterday, just now I got the results with Q 533 connected with good transistor as follow:
pin71 3.1v
pin72 3.6v
pin80 3.1v
pin81 3.8-4v
The unit can power on but shut off even more quick than no transistors on it.

Also tried to connect Q533 with bad transistor, pin 71 got 0v and machine power on then went to overloading protection with HDMI blinking .
So what I should do next to keep machine work all the time, even ok without protection function fixed.
Thanks again and willing to hear your suggestion!

mastertech
Global Moderator

Posts: 3,538

Pioneer VSX-921k power on fail with MCACC blinking Feb 21, 2016 10:58:00 GMT -5

Quote

Post by mastertech on Feb 21, 2016 10:58:00 GMT -5

Feb 21, 2016 10:52:22 GMT -5 youyoudeyou said:

Feb 19, 2016 11:18:33 GMT -5 mastertech said:

Also tried to connect Q533 with bad transistor, pin 71 got 0v and machine power on then went to overloading protection with HDMI blinking .

What makes you think that transistor was bad?

youyoudeyou
New Member

Posts: 17

Pioneer VSX-921k power on fail with MCACC blinking Feb 21, 2016 11:23:15 GMT -5 via Tapatalk

Quote

Post by youyoudeyou on Feb 21, 2016 11:23:15 GMT -5

Feb 21, 2016 10:58:00 GMT -5 mastertech said:

Feb 21, 2016 10:52:22 GMT -5 youyoudeyou said:

Also tried to connect Q533 with bad transistor, pin 71 got 0v and machine power on then went to overloading protection with HDMI blinking .

What makes you think that transistor was bad?

The transistors I thought it's bad got ~0.6to0.9v between base and emitter by both 2 direction under diodes mode, the good one no similar issue. Pls suggest if I did something wrong with it, thanks!

mastertech Global Moderator Posts: 3,538	Pioneer VSX-921k power on fail with MCACC blinking Feb 21, 2016 11:35:10 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by mastertech on Feb 21, 2016 11:35:10 GMT -5 At this point we need to be sure. What was your reading base to collector and emitter to collector?
	MT

youyoudeyou
New Member

Posts: 17

Pioneer VSX-921k power on fail with MCACC blinking Feb 23, 2016 10:06:24 GMT -5 via Tapatalk

Quote

Post by youyoudeyou on Feb 23, 2016 10:06:24 GMT -5

Feb 21, 2016 11:35:10 GMT -5 mastertech said:

At this point we need to be sure. What was your reading base to collector and emitter to collector?

just now I collect the resistance and diode mode voltage for all 5 transistors, The manual said the 5 transistors are exactly the same,Ican't figure out why each one have different value!Some thing wrong with my DMM?
.

mastertech Global Moderator Posts: 3,538	Pioneer VSX-921k power on fail with MCACC blinking Feb 23, 2016 12:20:21 GMT -5 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by mastertech on Feb 23, 2016 12:20:21 GMT -5 Your right. Those readings make no sense at all. Maybe pick up another cheap DMM.
	MT

albertto: Hi everyone. This is my first post here, so greetings to everyone. I hope to help and get helped in my diy prjects or other stuff. Thank you in advice!! Nov 2, 2024 12:45:30 GMT -5 *

zerolearner: Hi team members I'm new to the forum. I have denon X2000 firm issue I replaced the new ADSP IC but upload the firmware via USB port I got a error message connection failed 5A. FLAG0 present 0.84V is there any JTAG programmer for update the firmware. Sept 30, 2024 22:36:28 GMT -5

redpill: Would you able to provide more details in regards to your fix. Did you replace faulty unit or fixed yourself? I'm having similar problem and wonder how to approach it. Thanks. Lucas. Sept 8, 2024 1:10:29 GMT -5