Star Trek - Asteroids Conversion - Help getting her running

just look at SaminVA schematic where p4 is. brown = +5 , vio=-5 black=gnd, etc.
 
I have heard nothing but bad things about the original power supply so I didn't even consider checking mine out and rebuilding it; my game came with a switcher and I replaced it with a switcher and the VectorLabs power board.

Ask Gamefixer how many Star Trek boards he's fixed that had catastrophic failures that took out a zillion components and couple that with lots of talk of the power supply taking lots of stuff out when it fails and that was just somewhere I didn't want to go. My Star Trek was tormented enough as it was; I didn't need that added on top.

And this is coming from someone that's a big fan of keeping things original wherever possible. But not with that power supply. Not me. Unlike Cwilbar, I'm NOT capable of diagnosing and fixing massively damaged boards.

Now if this were a Midway MCR linear power board, I'd be the first one to encourage you to rebuild it rather than go with a switcher. But not this one.

Edit: I should add that I do use the original power supply for its audio amplification because that makes for better sound in the game than the VL equivalent on the power board.
 
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Technically I chose Pole Position but this keeps bugging me so I dove into this real quick first. "Real quick"...lol.

Man, Pole is another hell of a choice to get your feet wet on.

Only way you could have made it harder would have been getting a dead Cinematronics game. :)
 
Man, Pole is another hell of a choice to get your feet wet on.

Only way you could have made it harder would have been getting a dead Cinematronics game. :)

Don't forget the Omega Race with acid damage. :)
 
Yep...lol. But it seemed consistent. I've only seen 1 working board set for sale in months.

There's a reason for that. :)

I don't know what the ratio is between PP projects and actual working ones but it's probably fairly large.
 
Transformer sends out like 60v if I remember right but we lose it at the power supply. We're trying to figure out where it picks up chassis ground...

the transformer puts out a bunch of different voltages but I believe you are referring to the AC IN on the power supply.

In the attached you can see which AC in lines go to the various Bridge Rectifiers for the various DC voltage supplies. I couldn't find a quick reference on what those voltages should be but assume @ 8-10vAC for +5 volt line and @ 15-18v for +12v line etc.

basically..i think.. measure pins 1&3 on ACinput for the AC voltage feeding +12/-12v, pins 5&7 for +/-5v, and 8&10 for audio power.

>>edit>>
this image isn't that great but I went ahead and tested mine.
I get @26vac on pin1&3 (12v line) @ 16vac on pin5&7 (5v line) and @ 26vac on pins8&10 audio amp line.

others feel free to correct my terminolgy etc.
 

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>>edit>>
this image isn't that great but I went ahead and tested mine.
I get @26vac on pin1&3 (12v line) @ 16vac on pin5&7 (5v line) and @ 26vac on pins8&10 audio amp line.

others feel free to correct my terminolgy etc.


Wow, what a piss poor design. Fuses AFTER the bridge rectifiers. GREAT IDEA SEGA!

To the OP, Fix that supply if you really want too. I wouldnt bother with it...

You can either Vector Labs --> ATX it or do as I suggested and run the +5 to an outboard switcher.

Or mess with the original supply. Just know that when it goes it will take other things with it.
 
the transformer puts out a bunch of different voltages but I believe you are referring to the AC IN on the power supply.

In the attached you can see which AC in lines go to the various Bridge Rectifiers for the various DC voltage supplies. I couldn't find a quick reference on what those voltages should be but assume @ 8-10vAC for +5 volt line and @ 15-18v for +12v line etc.

basically..i think.. measure pins 1&3 on ACinput for the AC voltage feeding +12/-12v, pins 5&7 for +/-5v, and 8&10 for audio power.

>>edit>>
this image isn't that great but I went ahead and tested mine.
I get @26vac on pin1&3 (12v line) @ 16vac on pin5&7 (5v line) and @ 26vac on pins8&10 audio amp line.

others feel free to correct my terminolgy etc.

I wasn't doing it my dad was... but I think it was 60v or so coming from measuring that burnt plug that goes into the power supply from the transformer. When it wasn't plugged into the power supply. Once it hits the power supply it dies.
 
Wow, what a piss poor design. Fuses AFTER the bridge rectifiers. GREAT IDEA SEGA!

To the OP, Fix that supply if you really want too. I wouldnt bother with it...

You can either Vector Labs --> ATX it or do as I suggested and run the +5 to an outboard switcher.

Or mess with the original supply. Just know that when it goes it will take other things with it.

I'm not arguing it's a bad design. I probably will replace it with other suggestions like you're saying. I'm not sure... But I do want to fix the original system first because it just feels right to do so. I'll probably blow the machine up along the way but let's hope not...
 
I'm not arguing it's a bad design. I probably will replace it with other suggestions like you're saying. I'm not sure... But I do want to fix the original system first because it just feels right to do so. I'll probably blow the machine up along the way but let's hope not...

The trick is to NOT plug the monitor in until you are 200% sure the boards are outputting a good signal.
 
I have 3 Star Trek's all with original power supply's which I have not rebuilt and still are working. I really should rebuild them but the only thing I have done to them is replace the burnt pins and replaced the harness connectors with trifurcon pins. If the fuses in the power supply are all good then it may be ok and just not getting AC power. Their really should be a 5 amp slow blow fuse between the on/off switch and the EMI filter before it connects to the power transformer. If their's no AC going into the transformer then their can be no AC from the transformer to the AC input of the power supply. If you have AC going in then check your DC out voltages. You need to get a manual or down load one on line. Wile testing be sure to unplug the monitor and boards. When you have +5,-5,+12 and -12 then you can connect the boards and see if the game plays blind. Just take it one step at a time.
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The slow blow fuse was an 8amp so I gotta fix that. It was built into the back side of the transformer chassis rather then installed somewhere visible. It appears the fuse is after the EMI filter but before the transformer so hopefully that doesn't matter.

A lot of colors on the wires don't match the original colors in my manual. Not sure if that's due to the conversion and maybe they used the Asteroids wiring?

On one page the manual also shows the power supply with a ground to chassis but we don't see that. Not sure if the manual was drawn wrong or my machine is odd.
 
The trick is to NOT plug the monitor in until you are 200% sure the boards are outputting a good signal.

Well I'm employing that trick now but the guy I got it from was toying with it and I toyed with it after without doing that. Hopefully it didn't damage anything since the boards and monitor didn't appear to be getting any power.

Everything we do now has the boards and monitor unplugged.
 
I wasn't doing it my dad was... but I think it was 60v or so coming from measuring that burnt plug that goes into the power supply from the transformer. When it wasn't plugged into the power supply. Once it hits the power supply it dies.

no worries. yes you should fuse it back down to 5amp but that wouldn't stop me from continuing to test the power supply.

here is your picture of the p25 (AC IN) again.

The red wire to the right is pin 10....the two violet wires are 5&7.....and brown farthest to left is 1. Measure where I stated above and revert with your results.
>>edit>> Probably already mentioned but you are going to need to repin this and put new headers on anyway w/ that burnt common pin.
>>edit again>> went back and read my thread this comment from gamefixer :)

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We noticed a couple times when we plugged it in the fan would rotate for a split second and then die.

Well we went to do these tests and it did it again which caught my dads attention. Turns out the dang plug is bad!...lol. We replaced it and everything comes on. We got all the 12's and 5's. We tested all those mentioned pins and they were almost matching exact. Within a digit.

We did not hook up the game boards or monitor yet. I'll do that tomorrow after I hear if there is any additional tests I should do first.

I feel dumb but at the same time I'm happy. My dad was wondering why things were fluctuating on us like that. That's one if the reasons we were ground hunting...
 

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When you do hook the game boards up, listen for audio at power up. If you dont have it coin the game up. If its there and you can start a game and it sounds like things are working as they should then its time to move onto the XY output from the board set.

If you're missing sound DONT connect the monitor. It may be working without sound but it may also be locked up and drawing messed up vectors.
 
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