Hello guys! It’s been a while since my last post here, but I didn’t waste the time 🙂
What I did next was uP PCB remove, capacitors discharge, supercap desolder. I left the PCB removed for a couple weeks and then I washed it with distilled water and compressed air. Several weeks after, I decided to power it and …you never guess… it didn’t work 🙂
Fortunately this is not the end of the story, check this out:
Yup, I’ve picked up another, this time fully functional DSP-AX2 unit! Finally I can check what this thing sounds like and man, what a great performance (never had of any better before).
The first thing I did after disassembly of newer receiver was replacing of already rusty supercap. This unit was more lucky and didn’t have it leaked like the first:
Next I decided to check the uP board from working receiver in dead unit – it worked.
Finally I’ve checked the most concerning for me PRY to GND transition voltage: old dead board has something close to 0V, whereas new has reasonable 0.6V one way and 1.7V oppposite.
Folks, please confirm my assumption: since PRY is generated straight out of uP, measures above indicate that uP is likely damaged and worth replacing.
I can found M30802SGP chip on ebay for around $5 shipped and someone who can help me to do the swap...
Thanks,
Andrey
What I did next was uP PCB remove, capacitors discharge, supercap desolder. I left the PCB removed for a couple weeks and then I washed it with distilled water and compressed air. Several weeks after, I decided to power it and …you never guess… it didn’t work 🙂
Fortunately this is not the end of the story, check this out:
Yup, I’ve picked up another, this time fully functional DSP-AX2 unit! Finally I can check what this thing sounds like and man, what a great performance (never had of any better before).
The first thing I did after disassembly of newer receiver was replacing of already rusty supercap. This unit was more lucky and didn’t have it leaked like the first:
Next I decided to check the uP board from working receiver in dead unit – it worked.
Finally I’ve checked the most concerning for me PRY to GND transition voltage: old dead board has something close to 0V, whereas new has reasonable 0.6V one way and 1.7V oppposite.
Folks, please confirm my assumption: since PRY is generated straight out of uP, measures above indicate that uP is likely damaged and worth replacing.
I can found M30802SGP chip on ebay for around $5 shipped and someone who can help me to do the swap...
Thanks,
Andrey
Hi,
It is possible that you need to buy it from directly from YAMAHA. You need to have the boostrap loaded in the micro. Without it the micro will not initializes. The worst thing for a micro it is energizes a relay. It does not matter how you protect it sometime on power ON/OFF will sap the micro port output. In one of the thread I advice you to remove the PRY wire from the board and wait for a second and turn on the relay or connected it to the +5. That will proof you that the problem it is in the PRY it is bad and you need a new micro. Do not connect any speaker while doing the test.
It is possible that you need to buy it from directly from YAMAHA. You need to have the boostrap loaded in the micro. Without it the micro will not initializes. The worst thing for a micro it is energizes a relay. It does not matter how you protect it sometime on power ON/OFF will sap the micro port output. In one of the thread I advice you to remove the PRY wire from the board and wait for a second and turn on the relay or connected it to the +5. That will proof you that the problem it is in the PRY it is bad and you need a new micro. Do not connect any speaker while doing the test.
Bootstrap... right 🙁
I think I tried shorting PRY to +5V without removing the wire... Relay was activated, but it didn't go any further. I'll remove PRY wire and try again.
I think I tried shorting PRY to +5V without removing the wire... Relay was activated, but it didn't go any further. I'll remove PRY wire and try again.
Why should this be a concern? The microprocessor does not drive the relay directly! It is buffered by Q311 and Q316 (configured as a darlington pair), so only a very small current (< 1mA) is flowing through 'PRY' to the base of Q311 on the sub power supply board. Q311 has a built-in 4K7 resistor in series with its base connection.
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