Dragon's Lair Fans - Arcade Lifestyle
General Chat => Technical Area => Topic started by: Belike on September 08, 2010, 12:28:12 PM
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I have a strange problem with my Vanguard pcb, when I switch the cab on, everything works great until the first game you play is over.
After the "Game Over" sign the screen collapses and I can see only vibrating lines.
If I switch it off and on again, I can play 1 game again, but after it acts the same way. :'(
Any ideas what could be the problem?
Otherwise if somebody have a working spare Vanguard pcb, I'm up for it! ;)
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Uh first check if it's a monitor or a PCB problem ?
Otherwise, the first game that's REALLY Game Over ;D ;D ;D ;D
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LoL! ;D
If I leave it in demo mode it doesn't collapse.
Could it be a monitor problem in this case?
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Wonder how it looks like. Can you post a video (youtube).
If it happens exactly at the same time every time it could also be a ROM problem.
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Wonder how it looks like. Can you post a video (youtube).
If it happens exactly at the same time every time it could also be a ROM problem.
Voila:
http://www.youtube.com/watch?v=OMJ90cCiMZI (http://www.youtube.com/watch?v=OMJ90cCiMZI)
It's starting to be interesting from 1min.16 sec. ;)
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Looks like a PCB problem to me. Looks like bad ROM code making it crash. Is there a test menu to check the ROMs ?
If not try to re-seat the (EP)ROMs carefully.
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That's not a monitor problem, the game itself crashes. Like André suggested it might be a ROM Error. Did you try first aid: removing, cleaning, and reseating all socketed Chips, esp. the Roms. Also check and reseat all ribbon cables (if any), and check the voltages. Increasing +5V slightly might help.
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I reseated everything in the pcb, and I have another nonworking board, so I could swap all the chips one by one, but it was worse than the original situation.I think if the +5 V wouldn't be correct, the pcb wouldn't start and play only 1 game. :(
There is no test menu and as I'm an electric noob, I don't know which roms are the "game" roms. :D
Maybe an eprom burner and a working pcb could help in this situation. ;)
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The game roms are supposed to look like this if it's an original board (which I assume):
(http://abload.de/img/img_4016tayq6.jpg)
Sound Roms should be marked "VGS".
Ok, increasing +5V is something like a shot in the dark, quick'n dirty means of first aid, but I've seen many boards behave in all kinds of strange ways when +5V was too low (or too high, for that matter). I'd give it a try, can't hurt (at least if you don't increase to 10V :D). Remember that for some boards +5.0 is too low.
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double post - please ignore
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and be sure to measure on the board and not on the power supply !
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Thanks guys, I will try what you advised! ;)
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I swapped only these game roms again, but nothing changed, the game running until 1st game over:
(http://lh4.ggpht.com/_-UA8BV99Des/TIjXHSUebSI/AAAAAAAABqA/_x-mqVk-zII/s800/vanguard%20003.jpg)
When I swap this big one next to the game roms, there is just a white screen:
(http://lh6.ggpht.com/_-UA8BV99Des/TIjXH3TuT-I/AAAAAAAABqE/MCV4j5tRhTs/s800/vanguard%20004.jpg)
There is also a big one on the lower pcb, if I swap that, it also doesn't work:
(http://lh5.ggpht.com/_-UA8BV99Des/TIjXIEHYTsI/AAAAAAAABqI/2Iipx-vC0hE/s800/vanguard%20005.jpg)
There are also 2 golden mostek chips, if I swap one of them, the game running partially in white:
(http://lh6.ggpht.com/_-UA8BV99Des/TIjXIbMgdGI/AAAAAAAABq8/6Erw-x-YP10/s800/vanguard%20006.jpg)
I couldn't try to set the 5V yet, I think the game roms are ok, I have a feeling, that one of the big ones or the mosteks is defective.
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The 6502 is the processor (the big one).
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The 6502 is the processor (the big one).
Is it possible, that the processor causes this problem?
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Is it possible, that the processor causes this problem?
I'd say anything is possible ;)
Try to find a 6502 on one of your other PCBs, this CPU was used on many games, so chances are you have one on a working game.
Then try that on your Vanguard.
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Possible yes. Likely....mmmmm.
If it _constantly_ crashes at the same time, I would normally say it's getting a fault in the program (=from the ROMs). The 6502 is doing SO many cycles without crashing on that video.....I think it's not likely that it's the 6502.
The other one you swapped in is obviously bad as it didn't run right ?
Be sure that it is a 6502 and not another variant (check the numbers on the IC).
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Possible yes. Likely....mmmmm.
If it _constantly_ crashes at the same time, I would normally say it's getting a fault in the program (=from the ROMs). The 6502 is doing SO many cycles without crashing on that video.....I think it's not likely that it's the 6502.
The other one you swapped in is obviously bad as it didn't run right ?
Be sure that it is a 6502 and not another variant (check the numbers on the IC).
Yes, the other boardset's processors are bad, the game didn't start with them.
I try to find one in a different pcb. ;)
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André and Laschek had the jackpot, that was a fu....g power supply problem.
The voltage was only 4.6 and since my friend did a 2 minute repair on that, it's working fine! ;D
I still don't understand, why did it work in demo mode and for 1 game with the broken power supply, but these are arcade machines, so anything could happen! ;D