Need help with commando pcb

DixieDawg

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Hi,

I am just getting started and got my first arcade game. It's a data east version of commando. The game seems to play fine but a lot of the background graphics are missing or bad. I have been doing a lot of reading and watching tutorial on arcade game repairs and this is what I have done so far:

1.Checked Power supply. It's at 5.1v
2.Checked power on the board. It's getting 5.0v
3.Unseated, cleaned legs, and replaced all rom chips
4.Cleaned board edge connectors.

I have ordered and will be trying to learn how to use a logic probe to help diagnose further.
Also I have ordered a GQ-4X usb programmer which I figured I would eventually need.

I would appreciate any advice on where to look next, what to do next etc. Is there any info available as to which roms contain which images? Might help me narrow my search as to which part(s) of the board is bad.

Thanks,
Eric
 

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Ultimately to fixbosrds you will want to get the schematics drawing to the game you are trying to fix and learn to read them... At least figure out what chips are in which sections of the game circuitry)
 
Thanks. I do have the schematics that are in the back of the Instruction Manual for the game. But now to try to learn how to read them...
 
For no concentrate on figuring out what section of the schematics has the circuitry you are intersted in. Atari schematics are usually good as they are usually drawn in separated parts many of the schematics have small comments that describe what goes on.

But if you are having issues say with the Sprites that move, try to find the parts of the schematic that deals with foreground sprites or motion video etc... Don't worry If you understand it or not yet... Just try to find it.. Then read any comments that it had a d try to identify the chips on the board that you see on the schematics or in the comments. Familiarizing yourself with schematics is step one and it gets easier the more you look at it.
 
There is a place in mame that goes inside the roms a bit and can tell you some things about the ram and the check sums but others can help you with that. I have found the rom files I think you need they are the commando world set (I think that is what you have) if not there is the other files here too.

http://www.rom-world.com/file.php?id=30903
 
,

On commando the schematics cover:

1.Scroll H position (Horizontal position?)
2.Scroll Video RAM
3.Scroll Video ROM
4.CPU - Z80
5.I/O Port
6.Sound by PSG (Not Sure what PSG means?)
7.Main Amp
8.Synchronous (Not sure what this means?)
9.Character Video RAM
10.Character Generator ROM
11.Color Mixer
12.Custom Chip
13. 96 Objects Data RAM
14. 24/96 Object Controller
15. Object Data Control
16. Object ROM
17.Line Buffer 1
18.Line Buffer 2

Looking at this list I would suspect maybe #2,3 and maybe 13 and 16

Not sure if character generator or character video refers to actual "letter" characters like a,b,c, etc? Any ideas.

Also any ideas on what kind of things would be on the "Custom Chip"?

The game plays fine and sound seems fine. However, alot of the background, mountains, some vehicles are not visible but the sodlier is still able to run into the invisible objects.


Thanks
 
On commando the schematics cover:

1.Scroll H position (Horizontal position?)
2.Scroll Video RAM
3.Scroll Video ROM
4.CPU - Z80
5.I/O Port
6.Sound by PSG (Not Sure what PSG means?)
7.Main Amp
8.Synchronous (Not sure what this means?)
9.Character Video RAM
10.Character Generator ROM
11.Color Mixer
12.Custom Chip
13. 96 Objects Data RAM
14. 24/96 Object Controller
15. Object Data Control
16. Object ROM
17.Line Buffer 1
18.Line Buffer 2

Looking at this list I would suspect maybe #2,3 and maybe 13 and 16

Not sure if character generator or character video refers to actual "letter" characters like a,b,c, etc? Any ideas.

Also any ideas on what kind of things would be on the "Custom Chip"?

The game plays fine and sound seems fine. However, alot of the background, mountains, some vehicles are not visible but the sodlier is still able to run into the invisible objects.


Thanks

I don't own one of them boards and have not seen the schematics so I would need the part number, many customs are just different clocks or buss drivers but it is hard to say without the part number.
 
I believe my Commando cabinet is a dedicated origional commando. It has a 44 pin Capcom to 56 pin Data East adapter with it. Does this mean i can use standard JAMMA boards with this cabinet?
 
I think i answered my own question. Looking at the pinout of the 56 pin data east adapter it does not exactly match the pinout of a standard jamma pinout. So no, it wont work :(
 
Which version of MAME runs with missing or corrupt roms?

I am trying to find a copy of MAME that is old enough to let me play games with missing or corrupt roms but able to run on a Windows 7 computer. So far after numerous tests the old ones aren't compatible and all the others I have tested won't run with a missing rom. Any suggestions on which version to use? Thanks!
 
Just an update and unfortunately a setback,

I have been doing a lot of reading and learning. Dumped all the eproms and tested them in mame. All working fine. Used diode test mode on the multimeter to identify some ICs with potential shorted to ground input pins as suggested by Randy Fromm on his arcade game repair video. Played around some with the logic probe but far from an expert yet. Then I won an auction for a 100% working commando on ebay for a very good price. The idea being that I could use it as a comparison to the bad board and help with my logic probe diagnostics. Three days after the auction was completed I get an email that he is refunding my money because the 100% working board "doesn't work"! Very frustrating! Watched the auction for half a week then waiting like Christmas for it to show up, only to find out Santa's not coming this year! Guess my options are to order some ICs and start replacing them or wait and hope a new commando eventually goes to auction for a good price.
 
Post a want ad in the wanted section of this forum. I'm sure someone has a working one to sell.

Brian
 
Just an update and unfortunately a setback,

I have been doing a lot of reading and learning. Dumped all the eproms and tested them in mame. All working fine. Used diode test mode on the multimeter to identify some ICs with potential shorted to ground input pins as suggested by Randy Fromm on his arcade game repair video. Played around some with the logic probe but far from an expert yet. Then I won an auction for a 100% working commando on ebay for a very good price. The idea being that I could use it as a comparison to the bad board and help with my logic probe diagnostics. Three days after the auction was completed I get an email that he is refunding my money because the 100% working board "doesn't work"! Very frustrating! Watched the auction for half a week then waiting like Christmas for it to show up, only to find out Santa's not coming this year! Guess my options are to order some ICs and start replacing them or wait and hope a new commando eventually goes to auction for a good price.

post a pic of the board and what it is doing and we all can help you more better. If the board is dead then look at the cpu with that logic probe and report back what pins are doing what. Some of the pins I am wanting to see are 21-40 and most should be pulsing but pin 26 < if memory is right is the reset and when board starts should be low and go and stay high.
 
The game plays fine so I believe the cpu is working correctly. Certain background images are missing like the grass, rock faces, some stone walls and there are occaisional blue bands that scroll down in the background as your soldier advances up the screen. I discovered from online research that the top board c-1 takes care of the backgrounds so I have been focusing my attention there. Will get back to you on the probing of those pins as soon as I have a chance to test them.

Getting an error trying to upload the board photos. Maybe they're too large filesize. Will redo them and get them uploaded.
 
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