Monday, October 24, 2011

Black Hole repair part 5

Finally worked a bit further on the Black Hole..
Last time I worked on it was about a month ago, the cpu didn't boot anymore after replacing a lot of corroded parts.

I can solder pretty good (not perfect), was sure I had put all the correct parts in the correct places, so thought it probably were 2 components shorting against each others..
Turns out my idea was correct. Investigated the cpu, measured continuity between every two solder points that were close together, and compared with a spare cpu board I have laying around.
Found two solder points that made continuity, that didn't on the other board. Visibly there wasn't anything wrong so it must have been a very thin trace.. Scratched between the solder points with the tip of the probe of the dmm and continuity was gone. Inspected the rest of the board, didn't find any other problems.

Put the cpu back in the game.. always an exciting moment.. and yes, after about 5 seconds the score displays illuminated !

At least one problem solved, we're making progress again.

The game still doesn't work completely. Popbumpers don't work. At least the fuses don't immeadiately blow anymore, they just don't work at all. Will trace the +5v again on the boards..
Flippers also don't work :-( I'll have to check the Q-replay underneath the playfield.
Some coils do work, like the outhole and drop target reset coils.

For some reason I have problems with this Q-relay. One set of contact points on the game just burns ?!! as if there's too much voltage going over it ?? Last month when troubleshooting it I had already replaced the blade contacts with those from the Q-relay of a game I parted.. they were good..
Now the cpu is fixed, I had started a game, heard a fuzzing noise from the back of the machine.. inspected the Q relay and one set of contactpoints is again a bit burnt ?? :-(

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