A few weeks ago my trusty Yamaha RX-V667, which I've had for 9yrs since new, stopped working without warning. We have all our HDMI sources connected to it, and these could no longer be accessed. The standby light has gone out and neither the remote or power button can start the receiver. When I press the power button I cannot hear any relays.
Before this, the amp has never put a foot wrong and sound quality was perfect.
I have downloaded the service manual from here:
https://elektrotanya.com/yamaha_rx-v.../download.html
I've scoured this forum and the internet for threads on dead Yamaha AV receivers, but have drawn a bit of a blank in finding a solution that works. Here is what I've tried so far:
- The three button 'reset procedure' from the service manual.
- Checked the main plug fuse and the internal fuse in the power supply. Both fine.
- Checked continuity of the primary winding on the main transformer. Measured fine.
- Visual check for 'toasted' components or bad caps. Nothing obvious.
- Having read about 'C405' on Yamaha receivers (and watched the EEVblog video), I replaced the 22nf 600V capacitors C3701 and C3717 on the "Video(2)" board that seem to do a similar job in the standby circuit. There was no change, and the old capacitors tested fine on my multimeter.
- Bridged the main relay in an attempt to get it to power up, but still nothing lit up.
- Checked voltage across the main relay and it's basically zero regardless of the power button being pressed or not.
- Removed the "Video(2)" standby power supply board and powered it up on the bench. All of the outputs at CB379 are as expected - I get 5.49V on the +5.5V power supply.
Where it gets interesting is that when the receiver is fully assembled, I only measure about +0.2V on the +5.5V inputs to CB73 on the main 'Digital' board (with all the HDMI sockets). If I unplug the connector I measure +5.49V again. My meter is showing continuity between the +5.5V and DGND inputs at CB73. This makes me think that something on that board is shorted somewhere, which is a shame as it looks like the hardest board to repair!
Have also tried to get a reading on a +3.3V line and that was at close to 0V also.
I'm fairly sure it's an issue with the parts of the amp connected to standby power at this stage. According to the block diagram on pg83 of the manual, the +5.5V feeds a bunch of regulators on the main 'Digital' board. At this point I'm stuck with how to proceed.
In terms of equipment and experience, I have a decent temperature controlled iron and a multimeter. I don't own a scope or any other test/repair equipment. I've completed successful repairs in the past e.g. re-capping a motherboard, repaired traces and battery damage in old computers, rebuilt a valve amp with new components, but am not experienced in fault finding and have never attempted any surface mount soldering. I can read a circuit diagram but most of the time don't understand how the circuit actually works. I'm basically a novice, but not a "n00b".
It seems a shame to throw the receiver out if there could be a simple fix. I don't have a 4K TV yet, and don't plan on upgrading from 5.1 to Atmos any time soon. I also don't have a tonne of time to spend on this as I've got a 9 month old in the house. Am therefore looking to see if anyone has any suggestions of simple things I can try or has resolved a similar issue before. Any advice gratefully received.
Before this, the amp has never put a foot wrong and sound quality was perfect.
I have downloaded the service manual from here:
https://elektrotanya.com/yamaha_rx-v.../download.html
I've scoured this forum and the internet for threads on dead Yamaha AV receivers, but have drawn a bit of a blank in finding a solution that works. Here is what I've tried so far:
- The three button 'reset procedure' from the service manual.
- Checked the main plug fuse and the internal fuse in the power supply. Both fine.
- Checked continuity of the primary winding on the main transformer. Measured fine.
- Visual check for 'toasted' components or bad caps. Nothing obvious.
- Having read about 'C405' on Yamaha receivers (and watched the EEVblog video), I replaced the 22nf 600V capacitors C3701 and C3717 on the "Video(2)" board that seem to do a similar job in the standby circuit. There was no change, and the old capacitors tested fine on my multimeter.
- Bridged the main relay in an attempt to get it to power up, but still nothing lit up.
- Checked voltage across the main relay and it's basically zero regardless of the power button being pressed or not.
- Removed the "Video(2)" standby power supply board and powered it up on the bench. All of the outputs at CB379 are as expected - I get 5.49V on the +5.5V power supply.
Where it gets interesting is that when the receiver is fully assembled, I only measure about +0.2V on the +5.5V inputs to CB73 on the main 'Digital' board (with all the HDMI sockets). If I unplug the connector I measure +5.49V again. My meter is showing continuity between the +5.5V and DGND inputs at CB73. This makes me think that something on that board is shorted somewhere, which is a shame as it looks like the hardest board to repair!
Have also tried to get a reading on a +3.3V line and that was at close to 0V also.
I'm fairly sure it's an issue with the parts of the amp connected to standby power at this stage. According to the block diagram on pg83 of the manual, the +5.5V feeds a bunch of regulators on the main 'Digital' board. At this point I'm stuck with how to proceed.
In terms of equipment and experience, I have a decent temperature controlled iron and a multimeter. I don't own a scope or any other test/repair equipment. I've completed successful repairs in the past e.g. re-capping a motherboard, repaired traces and battery damage in old computers, rebuilt a valve amp with new components, but am not experienced in fault finding and have never attempted any surface mount soldering. I can read a circuit diagram but most of the time don't understand how the circuit actually works. I'm basically a novice, but not a "n00b".
It seems a shame to throw the receiver out if there could be a simple fix. I don't have a 4K TV yet, and don't plan on upgrading from 5.1 to Atmos any time soon. I also don't have a tonne of time to spend on this as I've got a 9 month old in the house. Am therefore looking to see if anyone has any suggestions of simple things I can try or has resolved a similar issue before. Any advice gratefully received.
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