Yamaha RX-V479: Bridge Rectifier Question

[manfriend]

I have a Yamaha receiver and the self diagnosis points to a faulty bridge rectifier activating the self protection circuit. It calls for a TS6P03G 6A 200V. The size is very specific as I have discovered and I can't find one any where. Would it be safe to deviate from the amp rating? The volts? Here's the data sheet on what I need: https://www.mouser.com/datasheet/2/3...15-1115464.pdf. Do I need to keep turning over rocks till I find this bridge rectifier? Thanks for any help.

[diif]

Re: Bridge Rectifier Question

Are you sure it's the bridge rectifier ? I wouldn't expect the receiver to turn on if it has failed.

[redwire]

Re: Bridge Rectifier Question

You can test the four diodes inside the bridge if you pull the part.
If in-circuit testing, be careful the big filter caps are discharged so they don't zap your multimeter. Those big caps cause a long delay getting a Vf reading, but it sounds like you suspect an open diode. A shorted diode would pop the main fuse.

Protection circuit trip is most likely a failed power amplifier.

Consider GBJ series of bridge rectifiers, like a GBJ1002 10A 200V or higher PIV, in that same package.

[budm]

Re: Bridge Rectifier Question

Model number of the YAMAHA will help also.

[manfriend]

Re: Bridge Rectifier Question

Rx-v479

[manfriend]

Re: Bridge Rectifier Question

You can test the four diodes inside the bridge if you pull the part.
If in-circuit testing, be careful the big filter caps are discharged so they don't zap your multimeter. Those big caps cause a long delay getting a Vf reading, but it sounds like you suspect an open diode. A shorted diode would pop the main fuse.

Protection circuit trip is most likely a failed power amplifier.

Consider GBJ series of bridge rectifiers, like a GBJ1002 10A 200V or higher PIV, in that same package.

The flow chart seems to point to excess heat from the bridge rectifier tripping the protection circuit. The only way I could turn the receiver on for more than 5 seconds was to use protection cancel mode and run through the self diagnosis. The power amplifier could be it as well. I'm attaching some mroe images.

[CapLeaker]

Re: Yamaha RX-V479: Bridge Rectifier Question

Nah, if the bridge rectifier is shorted, there wont be any power at all. Not even for a split second. I think there is something else shorted on that +51V or -51V line that sucks all the power away. So I suggest you look at the amp section first and look for shorted transistor(s) output, driver and predriver.

[manfriend]

Re: Yamaha RX-V479: Bridge Rectifier Question

Heeding CapLeaker's advice I started working back from the bridge rectifier and pulling and checking components. The first things are two big caps both 8200uf 63v. They both test within 8% of the 8200uf but they both show 0.00 ESR on my Peak ESR70 meter. Is that normal for an audio capacitor? I checked them both with an ohm meter and one shows .OL and the other shows 2.395 M ohms and climbing.

Thanks for your sage advice.

[CapLeaker]

Re: Yamaha RX-V479: Bridge Rectifier Question

these are fine. What DC voltages are you measuring one those caps when you turn the amp on? These aren't audio caps, these are just the secondary filter caps for the 51V and minus 51V supply for the amplifier stage (transistors i mentioned before).
With the amp off and unplugged, turn your DMM to Diode mode and check the big output transistors for a short. Same thing on the driver transistor and the pre driver transistors I am betting on one of these transistors is shorted, putting the amp in protection mode. You can compare the left channel to the right channel.

The second last amp I repaired had a blown pre driver transistor that had failed.

[manfriend]

Re: Yamaha RX-V479: Bridge Rectifier Question

I've only checked one of the big transistors so far and it was fine and I haven't had a chance to pull any others yet. I will later this week and let you know what I have found. Thanks again for the advice!

[manfriend]

Re: Yamaha RX-V479: Bridge Rectifier Question

I got side tracked by life a few times the past couple of weeks. I have been pulling transistors and testing them, a lot of them, and so far I haven't found a bad one. I've been looking up their data sheet and using this guide to test them: https://vetco.net/blog/test-a-transi...04-12-25-37-07

[CapLeaker]

Re: Yamaha RX-V479: Bridge Rectifier Question

transistors do not only fail short, but the can act as if there is another diode, while there shouldn't be any. That's what happened to that other amp that I repaired.

[manfriend]

Re: Yamaha RX-V479: Bridge Rectifier Question

I have pulled and tested dozens of transistors and all of them tested good. I bought a Peak DCA75 and double checked them, all good. The bridge rectifier tested good. I don't see any sign of a bad cap. Thoughts?