U20 IC ST TNG

[robm]

Just wanted to check my diagnostics skills or lack thereof are on the right track.

I have an error on all switches in a column, when following pinrepair guides, i jumped the J207 and J209 connector pins in the switch edges test - all row switches were fine, but when it came to the column test, switch 71 wouldn't work.

Continuity between all switches in the column is fine (checked with multimeter).

Continuity between switches and CPU board is fine.

Continuity between switches and pin 12 (one that is related to that column) of U20 is fine.

The solenoids that are activated by the switches fire during the solenoid test.

I assume U20 is stuffed a ULN2803A IC

If this is correct - do Jaycar (i can't find any IC's on their online store - but i bought some LM339's on the weekend) stock this IC or will Greg or MarkC stock it or where else do i find one (as well as a socket to suit)?

[MartyJ]

Hi Rob,

What game is it - I'm assuming WPC89?

Sounds like an identical problem I had with my Getaway

http://aussiepinball.com/index.php?topic=934.0

Mark has the ULN2803A's on his site no probs.  Not sure about the sockets...Check with them first otherwise Jaycar definately has them.

Does the board have batt damage at all?

I would replace the U18 & U19 as well whilst the board is out....

[robm]

Game is Star Trek TNG, no visible battery damage, but when i made a remote battery holder over the weekend, the batteries were within a poofteenth of leaking everywhere....but i couldn't see anything on either side of the board.

Yep sounds similar to your problem, your excitement at using your new soldering station in that post sounds just like me!!

I picked up one from Jaycar over the weekend and did my 1st PCB repair (new LM339 IC and socket) which turned out way better than expected.  Took plenty of time, sat at the table and had some Pink Floyd cranked....

[MartyJ]

Game is Star Trek TNG, no visible battery damage, but when i made a remote battery holder over the weekend, the batteries were within a poofteenth of leaking everywhere....but i couldn't see anything on either side of the board.

Yep sounds similar to your problem, your excitement at using your new soldering station in that post sounds just like me!!

I picked up one from Jaycar over the weekend and did my 1st PCB repair (new LM339 IC and socket) which turned out way better than expected.  Took plenty of time, sat at the table and had some Pink Floyd cranked....

Great stuff!

I actually quite enjoy doing PCB repairs now.  Not that I hope they break on my machines, but enjoy the challenge..!

Get yourself a new U20+socket and you'll be up and running in no time!

[Marty Machine]

Yep, that Chip is pretty much everywhere, either at the pin suppliers, or good ol Jaycar, Dick Smith etc etc...

Those drivers do some heavy work and suffer all kinds of glitches (depending on the machine they're in) so it's no surprise they "let go" from time to time.

MM.

[Strangeways]

sounds like you are on the right track, Rob.

[robm]

New socket and chip installed - game works perfectly!!!

Love a result like that

[Marty Machine]

That was almost too easy, do it again 

MM.

[ddstoys]

Good job diagnosed and fixed by the owner great work

[MartyJ]

New socket and chip installed - game works perfectly!!!

Love a result like that

 

[Strangeways]

too easy !

Well done