Hello All, new to this site, and looking forward to hearing all comments and help I can receive. Not even sure if this post is in the correct section. But here goes. I recently acquired a used Yamaha rx-v2095 receiver at a garage sale for $10 (along with a few other things). Some things I keep, some I resell. Cosmetically it looks ok, but unfortunately I have the same problem others have had. It shuts itself off. At first I was hoping it was from the heat. It has been sitting in my garage since I got it,til I had time to bring it in and take a look at it.
Being the middle of the summer and an unavoidable heat wave, I'm sure it was pretty warm inside. After sitting for only a minute inside my air conditioned home, I plugged it in and turned it on. I heard a click,than a second later another click. looked at the display and saw nothing. I did this a few times with the same results,except that I noticed the display flash for a split second everytime I would turn it on again. I figured it was too hot and let it cool for a few hours in the ac. While trying it again later, no different results. After reading some other users posts, I decided to try some things.
I took off the top and did a visual of the inside. Nothing looked damaged or out of place. While turning the unit on,I would notice a quiet springing sound until the other click. I did attempt to run the self diagnoses. It did show me a message. I had to keep running the diagnosis over and over until I was able to make out the message,since it only displayed for a split second. It said CHK SUM: F300 G / PS PRT : 0%.
I figured before I go crazy taking apart things I don't need to, I would look for suggestions from more experienced experts than myself. I am by no means an expert, but I am fairly capable of testing and repairing all types of things. I can read electrical schematics. My main trade is automotive repair so I am familiar with evolving electronics. Thanks in advance for any suggestions you have.
Being the middle of the summer and an unavoidable heat wave, I'm sure it was pretty warm inside. After sitting for only a minute inside my air conditioned home, I plugged it in and turned it on. I heard a click,than a second later another click. looked at the display and saw nothing. I did this a few times with the same results,except that I noticed the display flash for a split second everytime I would turn it on again. I figured it was too hot and let it cool for a few hours in the ac. While trying it again later, no different results. After reading some other users posts, I decided to try some things.
I took off the top and did a visual of the inside. Nothing looked damaged or out of place. While turning the unit on,I would notice a quiet springing sound until the other click. I did attempt to run the self diagnoses. It did show me a message. I had to keep running the diagnosis over and over until I was able to make out the message,since it only displayed for a split second. It said CHK SUM: F300 G / PS PRT : 0%.
I figured before I go crazy taking apart things I don't need to, I would look for suggestions from more experienced experts than myself. I am by no means an expert, but I am fairly capable of testing and repairing all types of things. I can read electrical schematics. My main trade is automotive repair so I am familiar with evolving electronics. Thanks in advance for any suggestions you have.
The AVR's are generally "impossible" to fix, however in this case I think you might be lucky.
The PS PRT 0% indicates a power supply problem, ie, abnormal voltage detected, abnormal
because the voltage was 0% of the expected voltage. This means, in plain english, that you
probably have a voltage regulator down, these should be reasonably accessible, on the top of the unit and heat sink mounted.
Download the service manual from hifiengine.
Certainly the CHK SUM will need to be sorted out however I think the amp is in protection because of the PS issue.
The PS PRT 0% indicates a power supply problem, ie, abnormal voltage detected, abnormal
because the voltage was 0% of the expected voltage. This means, in plain english, that you
probably have a voltage regulator down, these should be reasonably accessible, on the top of the unit and heat sink mounted.
Download the service manual from hifiengine.
Certainly the CHK SUM will need to be sorted out however I think the amp is in protection because of the PS issue.
Dc in the Yamaha i just repaired was measured wrt digital ground (of course). Measuring from analog ground was fine. They seem to come adrift ...
As for the stupid way the various rail voltages are sensed. They just add all the rails together through resistors, along with some transformer windings before the bridge and end up with ~1v which is fed into the cpu. Daft.
Thanks for the tip. Though I doubt I've the courage to have another look at them for a while yet. Happy tinkering with 2 channel amps...
The ability to fix these things (which are essentially simple computers hooked up to a bunch of amplifiers) is entirely dependent on the quality of the documentation. No documentation, no fixing the amp. Great documentation, easy fix. Middling documentation, like the yamaha's, fixable with some head scratching, once you realize the design oddities.
If you say so. I found the schematic a bit haphazard.
For reference (and they don't state this anywhere), various (but not all) DC rails are summed together through high valued (10-50k) resistors and poked into an A/D converter pin on the main CPU. That would be OK, if they didn't accompany it with summed voltages from the secondary windings of the main transformer, which should sum to zero, except when there is enough noise on the incoming mains to not sum to zero and trigger the dreaded PS PRT some random number error message then shut down. That is NOT ok. Cut those resistors out and stick a larger cap in the summing circuit for the rest of the DC rails.
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