Back to my dusty old MCU board

Took another look over the MCU board I bought on Ebay at the beginning of the month which was giving me some erratic behaviour.

I started off by taking the CPU out of its socket, using a small screwdriver in the corner and prising it out gently. I lightly stroked the screwdrive over every contact within the socket and then took the CPU and rubbed each of its sides (where the pins are) over a piece of 1200 grit wet & dry sandpaper (whilst it was dry) to clean the contacts and then inserted the CPU back into the socket (the right way round).

Then, using a sharp knife, I lightly scraped each of the connector pins on the outward facing side of every connector to get rid of any built-up grime.

I then straightened all of the bent component legs on the underside of the board.

I then took my soldering iron and repaired any dodgy looking solder joints – there were a few.

I then took my soldering iron tipped with solder and lightly stroked the tip against the outward facing side of each of the pins on every connector previously scraped with the knife – effectively re-tinning the pins on that side.

I then took out my current MCU board from the pinball and put in this “new” board, pre-loaded with batteries and an L-7 eprom and fired up the machine. And it worked.

I went into the menu and set the time and date, increased the number of balls per game to 5, turned off THING (it’s still not attached – and won’t be until I’ve finished the renovation) and disabled the minimum volume setting. All with no problems.

I then loaded up 10 credits and played a game. It all worked.


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