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From reading the thread, he hasn't checked he even has the -5v, nor the existance of a Negatron in his chain... so yeah, my guess is that's the culprit.
 
oh, I didn't know that. I pulled the -5V lead from the power cable on my MK2 and the LED light still comes on. One thing I would say is that there is a 'noise' when the PCB is going through the ROM check (either with or without a soundboard attached). Hard to explain what it sounds like (very soft beep) and I'd say it's much louder on the ROM test without -5V than with -5V.

So, it's go check -5V.
 
No, that's just letting you know what errors there are in the soundboard based on the number of tones the soundboard makes once you boot the board.

If you could hear 1 tone - the soundboard is 'fine' (not always correct but 99% of the time it is).

If you could hear 2 tones - U2 would be bad, etc.

I currently have one that is making 10 tones - I suspect that's one of the 6116 ram but it is isn't listed in that test menu. I had one that made 7 tones and that was 6116 RAM.

Your board is 'running' on the digital side (LED light is on) but I suspect there's something bad in the amplifier circuit - I can fix these, have fixed quite a few and I'd suspect it's the op amp. This is common to fail on those boards. If you can turn the volume up to the max and listen for any tiny sounds that may help. If you can barely hear the game sounds it will be that op amp.

You can also try running your finger on the solder side of the board on the pins of the main amplifier (that is attached to the large aluminium heat sink). If it makes load static noise you will know the main amp is ok.
However I running my finger under the large aluminum part and I hear some noise.
Now to misure - 5v I put the black on pin 1 and red on pin 5 of jamma connector?
 
Yup, like said via PM, your negatron is broken, ask for a replacement from the seller on ebay
 
Negatrons always ship low, I've purchased three now and that has been the case (maybe for safety or something).
Really its the same old story... Always check ALL voltages before looking for/blaming other unknown variables!
Ok, have you measured. Does it work? Does the board get -5v?
I know my Negatron has a small adjustment pot as well for the voltage
Post freaking 10 BTW, all this (following 41 posts) could have been avoided if ya just took da mans advice. 8|

/dickmode_off ;)
 
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