Star Trek SOS help (resolved)

TSB

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My SOS started acting up yesterday. I powered it on, played for a while, and then the monitor started blinking at me.
All 3 colors were fading out at the same time. After a few minutes, they would cut out, rather than fade out.

I connected the game to a spare monitor, but it did the same thing, so I plugged the cabinet monitor back in. (not the monitor)
I checked the video cable pins. I pulled the pins, cleaned them, checked for good tension. I also checked the other side, at the edge connector, and hit it with some fresh solder. (not the wire)
I checked the connector going from the card-rack lid to the XY Control & XY Timing boards.
I put fresh solder at the headers on both XY Control & XY Timing boards. They were looking grey, but not cold. New solder anyway.

I'm looking at the PCBs, now, tracking down where the signal's getting lost. Here's a vid (change the quality to 720p 60fps to see past the flickering):

 
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Doh sorry to hear that.. I believe there is someone here that repairs PCB stacks… thinking it's @BackInTime82 but my old man memory isn't all that reliable these days…

Need to send my spare Star Trek PCB stack for service as well…
 
Doh sorry to hear that.. I believe there is someone here that repairs PCB stacks… thinking it's BackInTime82 but my old man memory isn't all that reliable these days…
Yes, BackInTime82 is one of the G80 and G08 gurus here. Did a bang up job on my boards.
 
For sure. @BackInTime82 is the man. He chimed in multiple times when I was putting this (and another) machine together. Even reached out over the phone a time or two.
 
Long shot here. If you are using the original G80 power supply, check the -5v output.
If the -5v is not right.. the screen will not work.
or maybe Q2 on the XY control board is borderline..
Ran into the -5v thing a long time ago..

View attachment 835928
Ah hah! Beat me to it! Yes, please check all the components in this circuit. I've seen several boards, especially early revisions, have broken solder here because they used the legs of the transistors and resistors to form traces that weren't printed on the board.

If that does not solve the issue, check the 10 pin DC voltage harness on the power supply and cage side both. I've seen tarnished or fatigued pins cause issues with stable voltages resulting in the flicker of the RGB signal.

Good luck!
 
Long shot here. If you are using the original G80 power supply, check the -5v output.
If the -5v is not right.. the screen will not work.
or maybe Q2 on the XY control board is borderline..
Ran into the -5v thing a long time ago..

View attachment 835928
Ah hah! Beat me to it! Yes, please check all the components in this circuit. I've seen several boards, especially early revisions, have broken solder here because they used the legs of the transistors and resistors to form traces that weren't printed on the board.

If that does not solve the issue, check the 10 pin DC voltage harness on the power supply and cage side both. I've seen tarnished or fatigued pins cause issues with stable voltages resulting in the flicker of the RGB signal.

Good luck!

I've been digging through the Owner Manual scans, looking for one that shows my version of the XY Control Board.
Is there a difference? Here's mine:


Scratch that. They substituted a562 and c1959 with different pinouts.

IMG_1577.jpg
 
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Have you determined that you are getting a clean -5v out of that circuit? That's the part that matters. We had a bad LM7905 in the power supply putting out -5.3V and that was killing the video out, normally I don't think much about it being off by that little, but it mattered.... So the -5v needs to be pretty close in this case..
 
Depending how reproducible it is, but most likely a voltage fluctuation issue due to weak connectivity. Clean the edge pins, replace the all the pins on both ends of the 10 pin power harness with trifucon pins, and check the solder on all the header pins.
 
I've pulled the sled out, and will be replacing the headers on both the power supply and backplane. Just don't have any on-hand.
The harness is NOS, but I may re-pin with trifurcon for good measure.
 
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