Quoted from Randy_G:And...failure to launch
Mpu only flashed twice
Probably due to typical battery corrosion around the 5101 RAM chip at U8 on the MPU board.
Quoted from Randy_G:(but would that prevent booting up?)
Battery corrosion hits the socket at U8 due to proximity causing connectivity issues with the RAM chip at U8. On power-up a failure with U8 RAM test will cause the LED indicator to stop flashing after two flashes.
I really should start checking the pinwiki.com site more...there's a ton of info there!
Here's a picture of my Stern mpu-200 board...the batteries were totally green and I tossed them away.
So a lack of a 3rd flash means an issue with U8(or even perhaps the socket or traces).
The bottom edge of the board looks kind of good.
Quoted from CaptainNeo:bottom of that board looks amazing.
Indeed, I don't see any corrosion... That's a real nice looking board.
Pop out U8 (note the semicrcle notch on the left side of the chip). Make sure when you reinstall it later the notch is on the same side (left).
Carefully inspect the pins for any green/black tarnish.
Carefully inspect the socket with a magnifying glasss again looking for any green/dark tarnish in the sockets receptor pins.
If it all looks nice and shiny, then do the same with the RAM chip at U13 as it's also part of the same RAM test as U8 on power-up.
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