Yamaha HTR-6130 - Blown "front" channel

[mattpd]

I am rather new at AV repair, but have a good understanding of general electronic repair.

Someone asked if I could take a look at their broken receiver. They were using it to drive 8 speakers throughout their office, with 4 speakers connected to each of the two "A" speaker terminals.

The amp is rated for 8ohm minimum speakers, and they had four 8ohm speakers wired in parallel, giving it a 2ohm load on each channel. Although it worked like this for quite some time, I am thinking it stressed something out in the amp and it finally blew.

This thing will not produce sound out of the "front" speaker terminals of the "B" speakers. It will also not produce sound from the "A" speakers at all.

The center channel and surround channels on speakers "B" still work.

It's not a setting problem. I have been though all of the settings and also reset the whole thing, with no results.

I took it all the way apart to look for anything obvious. Did not see anything. Tested the FETs on the heat sink and they are not shorted.

There are two large multi-pin Sanyo chips on the heatsink. Looking at the data sheet of them, one of them is used to drive 2 channels, and the other is used to drive 3 channels. I am guessing that the chip that drives 2 channels (STK433-130) is supposed to be driving the "front" speakers and is probably bad.

Thoughts?

[budm]

Re: Yamaha HTR-6130 - Blown "front" channel

Service manual.
It does not show that it is in protection mode on the front panel?

[petehall347]

Re: Yamaha HTR-6130 - Blown "front" channel

maybe a blown fuse .

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

Service manual.
It does not show that it is in protection mode on the front panel?

No messages on screen.

After looking through the manual, it looks like the Sanyo IC that powers 2 channels is actually powering the surround left and right, which work fine.

It's the other Sanyo IC with 3 outputs that power the center, and front R and L.

I am kind of thinking it's the bigger Sanyo chip that may have failed. I may have been mistaken when I originally said center channel worked (going from memory). I know SL and SR are working though.

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

maybe a blown fuse .

The only obvious fuse that I see is on the power supply, which is fine. I will double check for pico fuses, but I don't think it has any (unless they are integrated inside those Sanyo ICs)

[petehall347]

Re: Yamaha HTR-6130 - Blown "front" channel

very much doubt there are fuses in the power-pack ic.s .. i have never seen it .
have come across plenty of smd fuses in units similar to yours .
if the ic blows it will likely be short circuit and outputting dc that should trip the protection circuit .
if its easy enough to get to you could voltages for the output pins to see if there is large dc voltage present .

[petehall347]

Re: Yamaha HTR-6130 - Blown "front" channel

i just skipped through the manual and noticed it has over-current protection . this should have protected the amp and speakers if the speakers were the problem .
also noticed you can do self checks and there should also be a record of faults . maybe best looking at recorded faults before going any further .

[madan1]

Re: Yamaha HTR-6130 - Blown "front" channel

Is there any sound output on the headphones and the HDMI ?


p.s. this unit has a pretty good self-diagnostic menu, so just follow the instructions from the service manual.. everything you need to pinpoint the problem is there.

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

i just skipped through the manual and noticed it has over-current protection . this should have protected the amp and speakers if the speakers were the problem .
also noticed you can do self checks and there should also be a record of faults . maybe best looking at recorded faults before going any further .

Thanks, will check for errors and SMD fuses.

[petehall347]

Re: Yamaha HTR-6130 - Blown "front" channel

i must say these units are far ahead of the ones i have tried fixing . i have never come across any with self diagnostics . just heed the warnings about defeating protection circuits .. i can see it can make it easy to look for dc current on the speaker terminals if protection is defeated though . if its like any protections i am used to it wont harm anything defeating it so long as there is no load at speaker terminals .

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

i must say these units are far ahead of the ones i have tried fixing . i have never come across any with self diagnostics . just heed the warnings about defeating protection circuits .. i can see it can make it easy to look for dc current on the speaker terminals if protection is defeated though . if its like any protections i am used to it wont harm anything defeating it so long as there is no load at speaker terminals .

I searched high and low for fuses but still just see the one main fuse on the power supply.

Time to put all these parts back together so I can check the diagnostic codes.

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

No history of protection in the error log, but I am afraid that I cleared the history when I did a factory reset of the unit. I probably should have checked for errors first.

I used the test tones in the diagnostic menu and confirmed that C, SL, and SR are all working, but the front speakers do not work on either "A" or "B" outputs. This is with protection disabled.

I think whatever is wrong, the unit can not detect the fault itself...

[petehall347]

Re: Yamaha HTR-6130 - Blown "front" channel

only real way of testing the output packs is to measure voltages for every pin and compare to the schematic or the data sheet .

[madan1]

Re: Yamaha HTR-6130 - Blown "front" channel

plug headphones and check if there is any sound on them

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

plug headphones and check if there is any sound on them

I will have to order an adapter. I only have 3.5mm headphones. Will update when I get adapter.

[budm]

Re: Yamaha HTR-6130 - Blown "front" channel

If you look at the service manual, block diagram, and circuit diagram: You will see that the output of ALL amplifier are fed to the speaker protection relays (5 of them). So you need to find out of the relays for dead channels are turned on or not, headphone jack is also fed through the relay.

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

If you look at the service manual, block diagram, and circuit diagram: You will see that the output of ALL amplifier are fed to the speaker protection relays (5 of them). So you need to find out of the relays for dead channels are turned on or not, headphone jack is also fed through the relay.

I guess a stuck relay would make sense because the unit isn't detecting any fault.

How would I go about testing them in circuit? Can I check continuity of the relays while the circuit is powered? Or is that a no-no?

[budm]

Re: Yamaha HTR-6130 - Blown "front" channel

The relay is normally OFF, it is turned on if no fault is detected that is why you need to find oyt if you do have DCV on the relay coil or not, if you do have correct dcv on the coil but the relay is still not closed then you will need new relay.
Show us the pictures of the relay as shown in the diagram.
Did you download the service manual and look through them?

[mattpd]

Re: Yamaha HTR-6130 - Blown "front" channel

The relay is normally OFF, it is turned on if no fault is detected that is why you need to find oyt if you do have DCV on the relay coil or not, if you do have correct dcv on the coil but the relay is still not closed then you will need new relay.
Show us the pictures of the relay as shown in the diagram.
Did you download the service manual and look through them?

Here are the 5 relays. The two closest to the top are the ones of concern.

[budm]

Re: Yamaha HTR-6130 - Blown "front" channel

The group of 4-pin are the relay contact, the group of 2-pin is the relay coil, so just check the DCV on those two pins when the unit is on.
Picture of the relays? There will be coil Voltage rating printed on top of the relay.