Yamaha rx v373 - no power

**tom66** · 10-22-2013, 01:05 PM

Re: Yamaha rx v373 - no power

Completely dead?
Check this video for similar fault
https://www.youtube.com/watch?v=J42wDUzgx7s

**mmoore5553** · 10-22-2013, 01:16 PM

Re: Yamaha rx v373 - no power

Yes it is completely dead when you hit the power button. I seen that video before but was unsure as I do not think i have that cap. I will take a picture when i get home. I was going to order an ESR meter but i do not do enough small component fixes.

If i still live in my apartment i would be happy to go dumpster diving for things to fix.

Once i get paid i was going to order bob parker meter - assembled of course.

I am too lazy to do things for myself but fix or put together other people's stuff I am game lol.

**tom66** · 10-22-2013, 01:58 PM

Re: Yamaha rx v373 - no power

ESR meter cannot test the cap shown in video. Only for electrolytic caps.

**mmoore5553** · 10-22-2013, 04:35 PM

Re: Yamaha rx v373 - no power

Wow i did not know that. You saved me some money. I tried to ohm them out in circuit and some read 980 ohms and others where open or showed 1 on multimeter. Then i just ran a continuous check with tone and only one cap actually beeped. I think i am going to replace them all but unsure. I do not know how to test the caps in circuit. But if i am replacing one might as well do all small ones. I have attached the board and the caps i will replace unless you do not think so.

Attached Files

**tom66** · 10-22-2013, 05:06 PM

Re: Yamaha rx v373 - no power

That does not use the low power standby design it is completely different, my video does not apply in this instance unfortunately.

**mmoore5553** · 10-22-2013, 05:08 PM

Re: Yamaha rx v373 - no power

I understand but voltage is clearly not getting there at all. I am unplugging the other boards and the voltage does not come up. I do not even hear a relay clicking on when i hit the power. Nothing happens at all. I found voltage on one cap and the other nothing.

**mmoore5553** · 10-22-2013, 05:24 PM

Re: Yamaha rx v373 - no power

Any suggestions as i been all over the board looking

**mmoore5553** · 10-22-2013, 05:47 PM

Re: Yamaha rx v373 - no power

It appears to have a standby via the schematics. Here are some shots. the only cap i see in standby is c1507. I take some tests points and do not see the 9.3 at all. I see around 11 volts. So i assume the relay is not kicking on. I also assume it is because it is in standby. I know i could be totally off but that is my thinking. Your thoughts ?

c1507 is the blue cap in the previous pictures.
i can provide full schematic if needed for anyone.

Attached Files

**mmoore5553** · 10-22-2013, 09:46 PM

Re: Yamaha rx v373 - no power

Here is another shot where it shows it is going straight into the the standby it appears. But also hits the transformer.

I did an ohm test on the transformer and it showed 2.6 I figured it would show higher out of circuit.

Attached Files

**budm** · 10-22-2013, 10:51 PM

Re: Yamaha rx v373 - no power

So at S9, you are getting about 11vdc? What do you get at PWR_RY?

**DJduck** · 10-23-2013, 01:30 AM

Re: Yamaha rx v373 - no power

I remember EEVblog did a video on an older Yamaha receiver that would not power up because one of those 500v poly film caps on the 5V rail was toasted.

**mmoore5553** · 10-23-2013, 06:17 AM

Re: Yamaha rx v373 - no power

Budm - I have 13.54 at S9 and at PWR_RY I have nothing.

DJduck - I have seen that video and my board is not the same layout but I have thought maybe c1507 causing the error but unable to test it. I do not know how to test the small ones but I did check c1507 has 120 volts AC running through it.

Also I checked the power button and only 1.5 volts was going up to it.

**tom66** · 10-23-2013, 07:34 AM

Re: Yamaha rx v373 - no power

The fact that you're seeing good standby voltage (variations are expected; that voltage is given when the amplifier has powered on fully and is producing audio) but no POW RY indicates the main board is somehow not sending the right signal. There will be a regulator on one of the boards somewhere knocking the 11V down to 5V or 3.3V; test that.

**budm** · 10-23-2013, 08:38 AM

Re: Yamaha rx v373 - no power

You need that 3V to turn the transistor which drive the power relay to supply the voltage to the transformer. So main board is not doing its job. BTW, the the transformer DC resistance will be very low, but at 60 Hz, the impedance will be a lot higher.

**mmoore5553** · 10-23-2013, 06:15 PM

Re: Yamaha rx v373 - no power

I am having trouble getting to it as it is on the heatsink. Can i power it on without the regulator being on the heat sink ? they have a bunch of caps in the way.

**mmoore5553** · 10-23-2013, 08:53 PM

Re: Yamaha rx v373 - no power

Okay I have to say sorry that I do not have this on my desk but i have a TV on it that i am waiting on parts but i have it on the ground trying to take readings but i am not getting anything. Do i need to have everything plugged up ? I do not have the hdmi and rca hooked up or the front panel. As i am just trying to find where the volts are being dropped to five. I am not finding any voltage now but 120 AC. Do i need to have something else plugged in ??

do not worry i have them sitting on cardboard. I have repaired a lot of things in my short life but a stereo is kicking my butt. i will take a laptop repair or tv or anything else but another one of these .

If you want to make fun of my work floor that is okay too.

Attached Files

**budm** · 10-23-2013, 09:19 PM

Re: Yamaha rx v373 - no power

When I work on something that is crowded and hard to get to check the voltage, I just solder a long piece of wire to the test point, hook eveything back together and just measure the test point on that wire with ref to the chassis..

**mmoore5553** · 10-24-2013, 08:35 PM

Re: Yamaha rx v373 - no power

Okay i got the bugger put back together without some parts that i believe do not need to be on and still unable to track some voltages down. I am almost ready to give up. Anyone want a fixer upper for free ..well just pay shipping. Hell i will even go in half to ship

I will even throw in the service manual i bought.

This is a shame though.

**mmoore5553** · 10-28-2013, 06:40 PM

Re: Yamaha rx v373 - no power

anyone wanting a receiver to toy with ?

Yamaha rx v373 - no power

Yamaha rx v373 - no power

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