GORF issue

buxtonore

Member
Joined
Mar 12, 2010
Messages
144
Reaction score
4
Location
Wixom, Michigan
Does anyone know which one of the boards, and which chip would cause this? I am able to start a game but it ends in about 10 seconds and the ship gets bombed immediately. Also the controls do not work. Thanks
 

Attachments

  • IMG_0841.jpeg
    IMG_0841.jpeg
    439.1 KB · Views: 38
  • IMG_0845.jpeg
    IMG_0845.jpeg
    559.6 KB · Views: 38
  • IMG_0846.jpeg
    IMG_0846.jpeg
    965.4 KB · Views: 38
Sounds like one of the 0066-117XX customs on the game board has gone south. The game board is the one that has all of the pins on the top that the connectors go into. There are two of those custom chips on that board. Swap them and see if anything changes.

Thanks,
Jason

Jason
 
Does anyone know which one of the boards, and which chip would cause this? I am able to start a game but it ends in about 10 seconds and the ship gets bombed immediately. Also the controls do not work. Thanks
It looks like you have some RAM issues. When you say "bombed immediately" I'm assuming you mean the player ship explodes immediately? This is likely caused by some of the stray extra pixels you see on the screen triggering the "hit detection" in the U15 custom as soon as the game starts. It's also possible the U15 custom is having an issue as well but I would start with the RAM.
 
was anyone else mind=blown when they discovered you can die if you touch the score of an enemy you killed? lol
 
Pattern board looks like its leaving behind crap. Had that happen on a set I had - took some work to whittle down the chip on the pattern board, but there it was... There is a test ROM out there for GORF that can validate if this is a RAM issue or not.
 
I too would vote for Ram.

I suspect that if you swap the two small boards in the back of the cage it would change what you're seeing on the screen. Swapping will not resolve the issue but it'll likely change the issue and confirm it's one of the ram cards (small boards).
 
There are Test-ROMs for Gorf avalable:

 
I too would vote for Ram.

I suspect that if you swap the two small boards in the back of the cage it would change what you're seeing on the screen. Swapping will not resolve the issue but it'll likely change the issue and confirm it's one of the ram cards (small boards).
You were right. I switched the ram cards and I have a slightly different pattern now.
 
There are Test-ROMs for Gorf avalable:

Where do you get the GORF Test-ROMs?
 
Where do you get the GORF Test-ROMs?
There are links to the .bin file in that post.

Note, that Mark's test will tell you first bad ram you get to (which may or may not be the only bad ram). So, you'd have to replace that with a new 4027 ram and then retest to find another/others which is bad.

If you have the original Bally test cards (like I do) it tests all 16 rams at once on each board. That can tell you if there are several and also help you determine when repairing any one ram board becomes cost prohibitive.

All that said, your image isn't horrible so probably one or two bad rams. And on that topic, I find that Twisty Wrist has the best prices on 4027's…. and they're currently on sale!

Good luck.

 
There are links to the .bin file in that post.

Note, that Mark's test will tell you first bad ram you get to (which may or may not be the only bad ram). So, you'd have to replace that with a new 4027 ram and then retest to find another/others which is bad.

If you have the original Bally test cards (like I do) it tests all 16 rams at once on each board. That can tell you if there are several and also help you determine when repairing any one ram board becomes cost prohibitive.

All that said, your image isn't horrible so probably one or two bad rams. And on that topic, I find that Twisty Wrist has the best prices on 4027's…. and they're currently on sale!

Good luck.

Thank you!
 
There are links to the .bin file in that post.

Note, that Mark's test will tell you first bad ram you get to (which may or may not be the only bad ram). So, you'd have to replace that with a new 4027 ram and then retest to find another/others which is bad.

If you have the original Bally test cards (like I do) it tests all 16 rams at once on each board. That can tell you if there are several and also help you determine when repairing any one ram board becomes cost prohibitive.

All that said, your image isn't horrible so probably one or two bad rams. And on that topic, I find that Twisty Wrist has the best prices on 4027's…. and they're currently on sale!

Good luck.


The RAMs are all interleaved -- any test code tests all of them at the same time.
The only difference is how the errors are reported.

The RAM test on the bally test cards isn't very exhaustive, but it at least finds completely dead RAMs.
 
The RAMs are all interleaved -- any test code tests all of them at the same time.
The only difference is how the errors are reported.

The RAM test on the bally test cards isn't very exhaustive, but it at least finds completely dead RAMs.
Thanks for the clarity, Mark, that's interesting. If I understand you correctly both tests (your ram test and the Bally test) are in effect testing all 16 rams but whereas the Bally test reports back on all 16, your test only reports back on one at a time. And using your test rom in order to understand if any more rams are bad, you'd have to replace that bad ram and test again. Correct?

Effectively, it doesn't change my original advice above that the Bally test is more helpful as it's not uncommon to find many (including all) rams on a board as bad so it's super helpful to know how many are bad so that you can assess the viability of repairing that board before you begin.

Typically my cutoff is about 3-4 rams as if it's more than that it's not worth the parts and labor to repair and just easier to source another board.

All that said, I appreciate the work you put into the test rom as it's proven super useful for many people, as most do not own the Bally test boards.
 
Thanks for the clarity, Mark, that's interesting. If I understand you correctly both tests (your ram test and the Bally test) are in effect testing all 16 rams but whereas the Bally test reports back on all 16, your test only reports back on one at a time. And using your test rom in order to understand if any more rams are bad, you'd have to replace that bad ram and test again. Correct?

The Bally test is only testing 1 card... mine tests both.

Effectively, it doesn't change my original advice above that the Bally test is more helpful as it's not uncommon to find many (including all) rams on a board as bad so it's super helpful to know how many are bad so that you can assess the viability of repairing that board before you begin.

If you have enough bad RAMs you can't really make out the results on either tester -- which is why I generally run with a logic analyzer hooked up and trigger on the bad RAM ID routine.
 
For posterity, the issue was a bad 4027 DRAM at location U16 on one of the ram cards.

The OP stated Mark's test rom did not report this issue, but the Bally test card quickly showed it bad on my bench.

It's been many years since I've used Mark's rom but it worked fine for me when I did use it. Had I thought about it I should have reenacted the test with Mark's rom on my bench before repairing.

Regardless, a single bad ram as predicted and OP has the boards back and reports all is well.
 
Back
Top Bottom