Pole Position - Missing red

bencao74

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Ritterhude, Bremen, Germany
Hey

I`m the owner of this wonderfull Pole Position sitdown.

http://4.bp.blogspot.com/-fQvrePELw7Y/T7zWjnzWxvI/AAAAAAAAEVo/pSmUedHKOQU/s320/IMG_0573.JPG

Here is the roadtrip driving thru half europe to get it. ;) I even bougth the topper from takeman and imported it to EU :)

http://bencao74.blogspot.de/2012/06/gameroom-pole-position-topper.html

So I really like this cab, but... the color red is missing.

I traced down the schematic for PIN 9 RED via R103->R59 -> down to

Custom PROM 136014-137.

This one has a strange addition from one of the pre-owners. There is capacitor between pin 12 and GND.

When I cut this capacitor I get screen with lot of funny characters with red working. But the game isn't playable.

When I leave the cap in place the game works without red.

So I guess this PROM is defect. Additionally the pre-owner was trying to bridge the PROM.

Where can I get a new one? Is it possible to re-program this PROM?

Thanks

Jochen
 
Sorry for digging out my old pole position thread. I've replaced ic 11e with a good one and the color red is working. Now the game is fun again :)

I still have a slight issue. In all the sprites are horizontal lines, looks oversized scanlines....

Anyone?
 
in case somebody has similar issues.

IMG_0177.JPG


pictures shows every second lines is missing.

After this reading this
showthread.php


I focused on 9F and 10F, the SRAM line buffers.

After replacing them it looks fine again:

IMG_0191.JPG


Here is the complete repair log
http://bencao74.blogspot.de/2012/11/pole-position-repair-log.html

IMG_0183.JPG

--> bad ic's

IMG_0184.JPG


desoldered them

IMG_0186.JPG


and replaced them
 
Thanks for posting this repair, this is one of the hardest games to get and keep working from what I have read.
 
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