Yamaha RX-V665 After 3 sec. shuts down

[linksys1127]

I am new to this so please bear with me. My in-laws have a RX-V665 av receiver that will not stay powered on. When it initially quit they heard a loud pop through the speakers and then no sound. I got a copy of the service manual and put it in the self diagnostic mode and it powers on for 3 seconds with "DC PRT: 000L" on the display before it powers off. It does this 3 times then will not allow anymore power ons until I unplug and replug back in. My troubleshooting abilities in electronics are limited and any guidance would be greatly appreciated. Just don't know where to begin.

[CapLeaker]

Re: Yamaha RX-V665 After 3 sec. shuts down

I'd say you have a shorted output transistor and the amp is in DC protect mode. As soon as the protection circuit senses DC on one of the output channels, it will protect itself and your speakers. So check the output transistors. Upload your service manual some pictures, so we have something to look at.

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

yamaha_rx-v665_htr-6260_sm.zip
Here is a compressed version of the service manual. Too large to send in original format. Thank you for your help!
Kevin

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

I'm fully capable using a multimeter just not so capable troubleshooting electronics but trying to learn. I'll take some photos when I get home from work today. Just need some guidance on where these transistors are located and testing them. Im guessing they would be shorted to ground if bad? Thank you

[CapLeaker]

Re: Yamaha RX-V665 After 3 sec. shuts down

There is a huge heatsink inside. So either there are "bricks" or individual transistors mounted to that heatsink. That's where we need to look at. I can't look at that zip file on my tablet, but I'll get it when I am on my PC again.

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

Not sure but here's what I found out. I powered the receiver on and checked each large ceramic resistor while the power was on. Took several tries due to it cycling off after a few seconds. I have three large bricks mounted to the large heat sink and seven large ceramic resistors near the large heatsinks.i got 50v DC on R1068 and 1v DC on R1067. Those 2 get their input from IC100 p/n STK433-330-E, one of the large brick transistors. The other resistors are 0 volts. Does that mean the brick transistor is the faulty component? Thank you

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

[ATTACH]144281[/ATTACH]
[ATTACH]144282[/ATTACH]
[ATTACH]144283[/ATTACH]

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down


Here's a pic of the three large IC's and the white ceramic resistors I checked for voltage during power-up. The one on the right is IC100. The one in question. Thank you again for your help on this!

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

Well, it flipped my picture. It's the IC on the top right.

[CapLeaker]

Re: Yamaha RX-V665 After 3 sec. shuts down

Look at the PDF page 116. There are the three output bricks. R1068 is on the Right channel output. So if you have 50V on that (or pin 4 on the brick), the IC100 is bad.
You need to find a replacement brick.
IC100:
pin 4/5 right speaker output
pin 6/7 center speaker output
pin 18/19 left speaker output

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down

Thank you so much for your help! I'll order a new IC brick and update this when I get it installed.

[linksys1127]

Re: Yamaha RX-V665 After 3 sec. shuts down


This is what the inside of the IC looks like. You can see several burned spots. Thanks to Capleaker's help in troubleshooting I replaced this IC and my in-laws are back in full surround sound. Thank you sir!

Kevin

[Flaviocb22]

Re: Yamaha RX-V665 After 3 sec. shuts down

do you think this works on a rx v379?