An interesting dilemma...

My Eight Ball needed display help. I bought two xPin displays with the intent of replacing all 5 at some point ($$).

So the two xPins are in Player 1 and 2 and work perfectly.

The Credit/BIP, Player 3 and Player 4 displays are plasmas. I have numeral issues with these displays however. In Display Test, I get an incorrect sequence (0-1-0-1-4-5~~~~-6-7~~~~-8-9). The tildes are there to represent the fact that when 5 and 7 come up, the displays flicker through several digits, but then lock right back down solid for '6' and '8'.

Sequence is very consistent.

I thought the displays were daisy chained in a way that meant if you had an issue with the MPU everything would be affected. I also understand that a bad decoder or weak resistors could cause strange things, but this is almost as if the top two displays are on one circuit and the bottom three are on a different circuit.

Thoughts?

-scott

Thanks guys - here are the results:

New xPin and Good plasma behave the same way all around:

P! and P2: Perfect

Credit/Match, P3 and P4: 2-3-2-3-6-7-6-7-blank-blank is the sequence

Note that the sequence is different in the bad displays today from last night (last night sequence was (0-1-0-1-4-5~~~~-6-7~~~~-8-9).

Supersonic displays are trashed...none are good ones (to my dismay). Just got Taxi finished so back upstairs to work on EB some more...

Will post as I know more.

-scott

OK - resoldered both the glass and connectors on the plasma displays...went ahead and replaced U10 and U11 for kicks as well but no changes.

Sometimes the number sequence will change in display test mode...in other words a different sequence will cycle, but once the sequence starts in display mode, it does not change.

So....

Next to check the logic on the decoders....

OK - thought I had this down somewhere...

What am I looking for in terms of signal on the scope from the 7734 BCD chip on a display...?

-scott

I cant as supersonic is completely disassembled...I dont have any other machines at present to test them in...

I sold too many early Bally's!!!

-scott

OK will check the continuity and go from there.

Thanks -

-scott