Silly Sega Turbo

dethfactor

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So my friend and I picked up a SEGA Turbo mini lastnight from a local guy who said that it worked at the place he bought it from but it was broke when he got it home.
Took the back cover off to find a master lock, a pencil, a tv antenna and a piece of a slot car track stuffed in the already small confines of the cab.

Still doing a little R&D on the cab but the machine just makes all sorts of crazy sounds when it's turned on. But every 1/20th of a power up it starts up fine for a little while then it goes bonkers again. I was able to get the tests working and everything passed, ROM and RAM then it seized up on the input tests and went crazy again.

I'm thinking it could be a power supply issue, as someone put in a switcher alongside the other PSU in the cab, which leaves little room. I swapped the switcher for a new one and I also pulled the board and reseated all the chips as well and it continues to go haywire.
Does anyone repair these things and would other boards be compatible with the mini if I need to replace my boards?

 
mines of the fritz too. not like that though. i suddenly get a black screen covered in yellow S's with the ambulance sound.
 
Turbo's are weird. When I was restoring mine, thought I read somewhere that there are certain chips that "expire" after awhile. Don't remember where I read that or what it was, but I thought I saw that. The power supply is also weird due to the 100V monitor. I had to mix and match between 2 different boardsets and power supplies before I finally got it to work. The sound board also goes bad frequently. ElDorado games can fix it for you, or swap a working set for your non-working set if it ends up being more tha $55/hr labor. If you've got sound of some sort, I'd send off the other boards first and then see if you actually have an issue with your sound board first. I don't know if anyone else works on them.
 
Turbo's are weird. When I was restoring mine, thought I read somewhere that there are certain chips that "expire" after awhile. Don't remember where I read that or what it was, but I thought I saw that. The power supply is also weird due to the 100V monitor. I had to mix and match between 2 different boardsets and power supplies before I finally got it to work. The sound board also goes bad frequently. ElDorado games can fix it for you, or swap a working set for your non-working set if it ends up being more tha $55/hr labor. If you've got sound of some sort, I'd send off the other boards first and then see if you actually have an issue with your sound board first. I don't know if anyone else works on them.

Great! I'll hit him up. Thanks for the 411.
 
Turbo's are weird. When I was restoring mine, thought I read somewhere that there are certain chips that "expire" after awhile. Don't remember where I read that or what it was, but I thought I saw that. The power supply is also weird due to the 100V monitor. I had to mix and match between 2 different boardsets and power supplies before I finally got it to work. The sound board also goes bad frequently. ElDorado games can fix it for you, or swap a working set for your non-working set if it ends up being more tha $55/hr labor. If you've got sound of some sort, I'd send off the other boards first and then see if you actually have an issue with your sound board first. I don't know if anyone else works on them.

I contacted El Dorado and they said they haven't worked on turbo boards for a long time and wanted $145 for the repair. I'm not sure my boards are haywire just yet and want to check the power supply out. I think there's something off about it though because it blew the fuse in my meter the other night and has crazy climbing voltages on the -12v leg. Anyone have any experience testing/repairing the PSU?
 
I contacted El Dorado and they said they haven't worked on turbo boards for a long time and wanted $145 for the repair. I'm not sure my boards are haywire just yet and want to check the power supply out. I think there's something off about it though because it blew the fuse in my meter the other night and has crazy climbing voltages on the -12v leg. Anyone have any experience testing/repairing the PSU?

I'd change that power supply if I were you. That was the first thing I did on my game. And I haven't had any issues with it since. (other than I have to rebuild my gas pedel when it gets warmer outside)
 
I'd change that power supply if I were you. That was the first thing I did on my game. And I haven't had any issues with it since. (other than I have to rebuild my gas pedel when it gets warmer outside)

The machine already has a switching adapter in it but it's still using it's old PSU as well, do you have instructions on how/what to replace on it?
 
The machine already has a switching adapter in it but it's still using it's old PSU as well, do you have instructions on how/what to replace on it?

Got a picture of it? I bet its still the original one. On mine I went out and replaced the switching power supply with a new one... Matching up the voltages with the ones on the old one.
 
Here's a pic of the guts. I swapped the switching adapter out for a new one the night I got it and it didn't fix anything of note. Looking at the schematics of the manual it looks like the game uses a lot of strange voltages. Is there a cap kit or something for the linear psu that might fix my issues?
ae4b1049.jpg
 
First test the transformer (primary and secondary side) to make sure that it is working properly. Don't forget that it's AC not DC. If that checks out, look at the board with the two light blue caps and the 2 black heat sinks. In my game (which I'm still working on) one of the voltage regulators on that board was getting hot. This pointed me to a short further down the line. I looked around and found that the sound board had a short (when the sound board was unplugged, the voltage regulator didn't get hot). I fixed the short and got sound.

After you are done checking for heat on the regulators, check the output voltages of everything else in the power supply, including the diode bride, which is small and is the part that delivers 8V unregulated to the CPU board near where the high score display plugs in. Fixing a problem with the diode bridge made my high score display light up.

If there was debris in the cab, then something may be shorted just from a small piece of metal touching a board or a piece on the psu. Maybe a good cleaning would help?

Also, if you order a new switcher, make sure the amps is the same as well. I hope this was helpful.
 
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