Tech: Car Action Schematic

[John Bennett]

[ukvac] Tech: Car Action Schematic
I'm currently playing around with a 'Car Action' board, which I believe is a
bootleg of Burnin' Rubber (aka Bump'n'Jump?). I've got it working almost
100%, but some of the sprites are still wrong. Unfortunately I can't find a
circuit diagram for the video circuitry. I've been using a Burger Time one
for the meantime, which seems quite accurate for the upper (mainly sound)
board, but bears precious little resemblance to the lower (video) board.

There's a picture of the offending board at
http://www.stumpie.com/tech/arcade/video-board-clean-small.jpg
and a really big one if you want to read the chip numbers at
http://www.stumpie.com/tech/arcade/video-board-clean.jpg

Does anyone have any ideas about what circuit diagrams might be available
which might be somewhere close to this board? Or, since it's a bootleg, am
I completely on my own?

Cheers
Chris
--
Chris Jones - chris@stumpie.com
http://www.stumpie.com/



DATA Imported from archives: originally posted by Chris Jones (chris@stumpie.com)

 

[P-Man]

Re: [ukvac] Tech: Car Action Schematic
i fixed one of these a while back, sans schematics..

i believe it uses 2114's for sprite or video ram.. just piggyback them until
you notice a difference and change the one that makes them ost idfference
after piggybackign and re-powering up...

i had a very similar problem (loads of garbage ON TOP of the actual game
display) turned out to be one of those. a quick 10 second piggyback check
found one making a lot of difference, ddn't fix it, just got a lot of
different tiles instead of just zero's and gabage.

Andy Welburn
www.andys-arcade.com

 

[John Bennett]

Re: [ukvac] Tech: Car Action Schematic
Andy wrote:
> i believe it uses 2114's for sprite or video ram.. just piggyback them
until
> you notice a difference and change the one that makes them ost idfference
> after piggybackign and re-powering up...

Thanks for the hint. In the short time I've been fiddling with arcade boards
I've already learnt to be deeply suspicious of 2114s! Unfortunately I've
already been through socketing them and tried replacing each one, but
without making any difference :-(

I'm also staggered at the sheer number of faults you can end up with on one
board set. My record so far is 10 separate faults on a Frogger board! Is it
because the machines are just left running as long as they'll play,
regardless of sound and graphics problems, and only given up on when they
won't take money any more?

Chris



DATA Imported from archives: originally posted by Chris Jones (chris@stumpie.com)