micle
Junior Member
Posts: 57
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Post by micle on Jan 10, 2022 4:44:03 GMT -5
Hello, my Pioneer vsx 920 receiver does not turn on anymore, I have seen several forums with similar problems but no one has found the damage, can we try?
I would be very grateful to anyone who helps me to fix it.
Symptoms: while it was connected with hdmi out to the TV it stops turning on / off in collaboration with the TV; the next day it switches off and switches on by itself, then the Mcacc LED flashes; finally it dies, no LED lights up and no components burned, it switches on and off only by holding down the power for 10 seconds or with tune down + multizone on / off, always freezing the word "POWER ON".
Now everything is disassembled.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 11, 2022 12:44:43 GMT -5
Hello, sorry for the language, I am from Italy, I give other data using the VSX-1020 service manual:
- if going into protection means standby, this receiver blocks first, it does not go into standby / protection, in fact the voltages are:
xolerr = 4.9V
xprotect = 5.0V
xcderr = 4.54V
xvdderr = 4.86V
x12verr = 3.3V (Shouldn't it be 12 or 1.2V?)
-On IC1501 pin136 = 3.3V (shouldn't it be 1.2V?)
-Then there is no 5V on pin 18 of the HDMI connections, is the voltage coming from the connected external cable?
I also kindly ask the major mastertech expert.
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Post by mastertech on Jan 11, 2022 16:27:38 GMT -5
Is you unit a 920 or 1020. I am looking at both manuals and they look different.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 11, 2022 18:34:45 GMT -5
Hello, the manual of the 920 must be wrong because it does not correspond to the 920 receiver, the 1020 instead is also given for the 1025 and 920 in fact corresponds.
Sorry I'm going to sleep, I'm not in a hurry.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 20, 2022 18:28:36 GMT -5
After several tests I still haven't seen where the fault is.
When everything is connected (just a click and everything is blocked), in the CN55 I find pin 6 (-VF) at -28Vdc, instead when the flat CN1405 is disconnected (it goes into protection with 2 clicks and mcacc flashes) I find pin 6 a 2 Vdc, but where does that negative voltage come from?
Should I perhaps check if the oscillator is faulty? But I only have a multimeter.
Any suggestions?
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Post by mastertech on Jan 21, 2022 18:34:51 GMT -5
Sorry I can not help you. I am going offline for a while as soon as I am finished up with someone else here.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 24, 2022 3:08:00 GMT -5
I am now desperate, during a test on the CN3004 / CN55 connection (pin 5, posistor) which initially was at 0v, it goes to 3.15v I hear the relay trip, but then it redeems and the central blue light turns on.
I have varied the resistance of the heatsink from 265 to 306 ohms, but still blue light remains, resistors and capacitors seem fine.
I read in a forum that the IC800 BGA chip often fails, will it be my case?
Now at least one LED lights up when powered.
Should I throw it out the window?
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Post by mastertech on Jan 24, 2022 16:22:57 GMT -5
Can you test Q5020 for shorted pins?
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micle
Junior Member
Posts: 57
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Post by micle on Jan 26, 2022 18:58:43 GMT -5
Hi mastertech, sorry for the delay, I had measured the Q5020 mounted in the first part (when the central blue led was not flashing yet) and it looked good, in fact xolerr was 4.9v, tomorrow I will disassemble everything again and tell you.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 27, 2022 13:22:57 GMT -5
Q5020 mounted, pin: 1)common, 2)IN, 3)OUT.
pin 1-2 = 42 KOhm
1-3 = 98 KOhm
2-3 = 140 KOhm
XOLERR on CN1250 = 4.88v (off power), 4.90v (on power).
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Post by mastertech on Jan 27, 2022 14:38:11 GMT -5
Where were you testing for x12verr?
What document did you see for ic1501, pin 136 voltage?
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micle
Junior Member
Posts: 57
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Post by micle on Jan 27, 2022 15:43:13 GMT -5
X12VERR pin 19 on CN1252, 0v (off power), 3.26v (on power).
IC1501 datasheet SiI9233ACTU printed on chip, but i realized that 1.2v was on pin 135 (not 136), i will have to check.
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micle
Junior Member
Posts: 57
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Post by micle on Jan 27, 2022 16:08:17 GMT -5
In the first part there was no 5v power supply even to the USB connection, it seemed no signal from the IC800 BGA chip.
Then the blue led turned on since I tested the posistor on pin 5 TEMP CN3003, going from 0.07v (first part) to 3.13v (second part).
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Post by mastertech on Jan 27, 2022 18:04:52 GMT -5
X12VERR pin 19 on CN1252, 0v (off power), 3.26v (on power). IC1501 datasheet SiI9233ACTU printed on chip, but i realized that 1.2v was on pin 135 (not 136), i will have to check. If you tested at pin 19 of cn1252 then it appears that 3.3v would be normal if not in protection however I could not find the 12v protection activation circuitry in this manual. Either I cannot not find it or it is not there but that circuit would have to pull the line low for that pin 19 to not have 3.3v Yes, it would be pin 135 that should have 1.2v I saw that and figured you just mixed up the pin numbers. If you want to do some testing to see what the problem is let me know. But you would have to stop just hunting around and I could guide you through some tests. |
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micle
Junior Member
Posts: 57
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Post by micle on Jan 27, 2022 19:33:58 GMT -5
Ok, I'll follow your directions.
Now everything is disassembled, when I reassemble I will try pin 135, but I think it is irrelevant for the protection it has.
Thank you very much.
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