Hi guys, I have this Yamaha for repair, the problem is when I push Power ON,, the amplifier goes Off in 1 second, I try Hard reset, same problem, I change all the capacitors on the Ic regulator circuit and same problem, I check all the audio output transistors all are good, I check voltage on Regulators board and I have a little low voltages on circuits like on 12 volts I have 11.6 volts, on -12 volts I have -11.4 volts , on 5 volts I have 4.81 volts, could someone tell me what I have to check now?
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Re: Yamaha RX-V3900
Look at this thread for information and things....
https://www.badcaps.net/forum/showth...t=yamaha+v3900
hopefully, you can get to the self-diagnostics and see what the results are.Last edited by budwich; 02-17-2022, 05:06 PM. -
Re: Yamaha RX-V3900
I try but I cannot because when I push Power On the amplifier shutoff immediatlyComment
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Re: Yamaha RX-V3900
what process are you following to get into the diagnostic menu? Follow the sequence in the manualComment
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Re: Yamaha RX-V3900
Self-diagnostic mode by holding down the 'enter' &preset tuning> buttons while pressing in the master on/off switch repeatedly many times but the message 'MAIN ON' stays on nothing else happening.I think the system has locked itself in.I try another thing , I push Info and Straight and put the Ac cord it's write Firmware update ( blinking) in the display but when I release these 2 buttons the amplifier goes OffLast edited by Fripacks; 02-19-2022, 09:43 AM.Comment
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Re: Yamaha RX-V3900
:-(... I have seen in the manual that if the system is in fault mode, you have to unplug it from the wall before trying to get into the self-diagnostics. Further, you don't keep repressing the power on key. According to the manual, you just press it once (to the ON position... it should be in the OFF position when unplugged) while holding the other two keys and wait for the appropriate display, then release them.Last edited by budwich; 02-19-2022, 12:48 PM.Comment
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Re: Yamaha RX-V3900
I try this thing too, always same problem, shut off in fraction of secondComment
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Re: Yamaha RX-V3900
just for confirmation.... you are using the master on/off button which is a "push in / out" button versus the "on/off standby" button which is a momentary button.
what's the history of the problem / unit?
there is a 9v "supply" along with -5v and 3.3v. You might list all the voltages that you checked on the power supply area specifically.Last edited by budwich; 02-21-2022, 12:35 PM.Comment
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Re: Yamaha RX-V3900
you might need to monitor the PDET line while you attempt your power up sequence to see what happens.
does the display light and display anything before it shuts down?Last edited by budwich; 02-21-2022, 09:48 PM.Comment
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Re: Yamaha RX-V3900
If it's going into protect due to over voltage or over current then you have to remove that condition first. The way to do that is to unplug one of the cables going from the hdmi board to the main board.
You'll have to have a look further or post some pictures as I have no idea about the receiver in question here.Comment
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Re: Yamaha RX-V3900
I try disconnect all connectors on HDMI board always same problem, see the photosAttached Filesif you find these attachements useful please consider making a small donation to the site
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Re: Yamaha RX-V3900
Someone?Comment
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Re: Yamaha RX-V3900
You can't disconnect ALL connectors. Try them one at a time or find the service manual for less guess work.Comment
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Re: Yamaha RX-V3900
Did you check the output voltages on the DCCNVT pcb?
I had an issue with the board, Channel 2 4.3v Dc. Rail was < 0.4VDC.
This was triggering the protect mode.
Note: During this fault you could not enter diagnostics mode, but could activate PSU’s to test voltages using the diag mode.
Replaced the DCCNVT board, problem resolved.Comment
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Laptop is HP Envy x360 13-bf0013dx, hp website link, it's an i7-1250U with 8 gig onboard ram.
Platform: ipa32 la-m024p rev 1b
Originally you'd plug power supply into it and it would take up to 1.2 amps and then drop to 200 milliamps and then go back up again to 1.2, staying all the while at 5 volts. Pressing power button would results in power LED blinking amber 3 times. 3.3 volt rail, 5.1 volt rail present, main power rail 8.8 volts. Power button test pads near EC chip 2.7 volts.
I found a short on the other side:
...10-04-2025, 05:03 PM -
Belongs to my son and he just says it stopped turning on. Any help greatly appreciated. Theres 240v in and fuse is ok but no power anywhere else.
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Hi everyone.
I am diagnosing my personal laptop, because it wont power on and no leds light up.
At the dc-in there are 8 pins, 1 and 2 shows healthy 19.66 volts. The next three are ground, but the 6th one shows .283 volts. This is strange to me, it should be 3.3 or 5 or aome volts not 0.283v. As I am new to this, I would like some guidance. Please someone advise me on what to check next.
Oh the boardview and schematics I am using is for a similar model as I cannot find the proper one anywhere. Quanta DA0P5HMB8F1 rev F. Nowhere on the internet.09-23-2025, 12:13 PM -
Hi All,
I have a Yamaha A-520 that has no sound output.
I notice after power up the protection protection relay does not click in.
I'd appreciate any pointers on where to start.
Many thanks.
Service Manual below:
https://www.badcaps.net/forum/attach...1&d=1641841819... -
I am Repairing this unit. It had many problems. One major one was the power transformer being about 4-5 volts low on the main B+ line which called for 66.5 Vols after the Main Filter caps but only showing about 62 Volts. Caps and the 5 amp Diode bridge were replaced which helped slightly.
The other strange problem was the small secondary winding from the PT which supplies 18 Volts AC to the "FM FLUORESCENT DISPLAY" circuit, and the small winding that supplies 8 Volts AC to the push button grain of wheat lamps. Those voltages were down from 18 Volts to 16 volts. Which was...
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