Help with Sega Turbo

[doubledown]

Well I just picked up my first arcade game, Sega/Gremlin Turbo, full size stand-up cabinet. The auction listed it as 95% working with a problem with the accelerator pedal. I got the unit today and going through the test screen, all functions seem to work properly. Steering wheel, gear shifter, gas pedal, and all buttons. When I attempt to play the game the pedal seems to work for the first 5-6 seconds, then for some reason after that, no response. After the time runs out I can use the pedal perfectly to input my initials. If I start a new game, again the pedal seems to work for 5-6 seconds then nothing. I also noticed that once I get to the second part of the first stage, the grassy highway with trees on either side, I notice that a set of trees every so often are screwed up as far as their display. Pixels are there, but they're not oriented properly. Any ideas?

[theking21083]

I'm just a novice at this but maybe one of the chips on the board is bad. That's the only thing that I could think of, hopefully some more experienced people can help out.

[Tempest]

It couldn't hurt to reseat all the chips. Sometimes there's a bad connection.

 

Tempest

[doubledown]

Thanks guys! I pulled and reseated all of the socketed chips and now the game works. The only problem are the distored pixels for the trees. It seems like every 5th set is screwed up. It doesn't affect game play obiviously just a cosmetic issue. Is it possible its a corrupted eprom chip?

[theking21083]

Sounds like one of the chips is bad. That's as much as I could tell you.

[Brian D. Deuel]

Thanks guys! I pulled and reseated all of the socketed chips and now the game works. The only problem are the distored pixels for the trees. It seems like every 5th set is screwed up. It doesn't affect game play obiviously just a cosmetic issue. Is it possible its a corrupted eprom chip?

 

Not sure what the problem is, but it's definitely a common one in Turbos. Mine did the same thing, and I've seen it in a few others. Eventually, the board just gave out in mine and I replaced it. It could be a ROM or RAM going bad.

[Cassidy Nolen]

Use your manual (download for free) and find what rom/ram are associated with those graphics. Swap the ram for that section with another one of the same kind and see if the problem moves to some other section.

 

In my Turbos (I have had/worked on about 20) all had VERY loose seated chips, bad contacts or corroded sockets. With some contact cleaner, a pencil eraser and a very steady hand I have managed to get them all going over the years and stay running (as far as I knew anyway).

 

I would also suggest pulling the pedal and cleaning the 28 years of crap out of it.

 

C

[doubledown]

I checked the manual and it lists the following roms that I think might be the culprit(s):

 

 

These are listed as having to do with scenery and the trees/bushes are what I'm seeing distorted pixels with. If lets say one is corrupted, can the files in the unzipped MAME rom for the game be burnt to EPROMS as replacements for these?

Edited April 8, 2008 by doubledown

[doubledown]

I was able to find all the light bulbs for the game today since all but one behind the bezel was still working. So I got the 5 behind the bezel, 2 for the gauges, and 2 for the coin slots. Also got a chance to clean up the control panel a little bit too. Here's a few pics:

 

 

 

It looks so pretty with all the lights working!

 

 

 

The side art is in pretty good shape. Just a few nicks here and there, but fairly nice overall.

 

[Cassidy Nolen]

These are listed as having to do with scenery and the trees/bushes are what I'm seeing distorted pixels with. If lets say one is corrupted, can the files in the unzipped MAME rom for the game be burnt to EPROMS as replacements for these?

 

That is exactly what to do. IIRC, that game will play with a ROM actually removed from the board. In other words, take one of them out, with the game off of course, and then turn it back on. See what graphics are crap (going to be a blank space I think) and then you'll isolate which one is bad. They are all 2764 EPROMS, easy enough to source (email me if you are desparate and I can probably dig one out of a board for you). Somebody here can burn a rom for you (haven't had my burner up in a few years).

 

Does the manual tell you associated video RAM as well? I remember the Turbo book being very helpful in a diagnostic repair.

 

C

[doubledown]

I've got plenty of 2764s and a rom burner as well. I'll see what I can figure out. I've got to replace the woofer today as the one that was in there had it's surround completely rotted away. Fortunately I have plenty of spare speakers in my closet. I use to be big into car stereos and just couldn't throw/give old stuff away.

[Tony Montana]

Looks sweet man. Congrats

 

Good luck getting the graphics glitch sorted