Star Trek SOS (start & credit swaps!)

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Hi;
I recently picked up a ST SOS and have ended up spending about a dozen hours on it and it still has issues. It was sold to me as working and during the shipping, the monitor was damaged. I swapped a spare G08 into the game and checked all voltages. The game boots and goes into attract. I play a game, (works correctly), get killed and enter my initals. The following, (second) attract is messed up. Letters are missing from words, the score is missing numbers and the dividing red lines that seperate the various areas of the display are missing in areas.

The display is not all jumbled up and skewed etc. Just some information is "missing".

I shut the game off for 10 seconds and reboot, then when I press the one or two player buttons, it puts credits on the game. I have to flip the credit switch to start a game.

This is not the situation when the game is "cold", the credit and start buttons function as they should.

I pulled the switcher that someone hacked into the game and installed a fully rebuilt Sega linear power supply. I had to also replace the hacked wires in the harness. And then while the harness was out, repinned them all with Trifurcon pins to insure a proper connection.

I set the voltage a little on the high side, +5.12 but that did not help either.

Also, there is much oxidation on the board cage, spinner encoder wheel and the CP hardware, it's like hair is growing all over the place, (I'll post those pics later on).

I pulled all the boards and happy to say that they were not corroded. I reseated all the socketed IC's on the CPU and ROM PCB's but still have the same issues. Since the speech, sounds and drawing work, I think that the problem is either on the CPU or ROM PCB's.
Am I going in the right direction?

I'll video the situation and post a link later as well.

ANY positive suggestions would be greatly appreciated.

Thanks in advance.
Jeff
 
Last edited:
When all else fails ...... Read the instructions!

I went through the manual, (finally) and had forgotten about the internal test feature!

I'll be running it in an hour or so and hopefully I'll have an answer.

Jeff
 
Hi;
I recently picked up a ST SOS and have ended up spending about a dozen hours on it and it still has issues. It was sold to me as working and during the shipping, the monitor was damaged. I swapped a spare G08 into the game and checked all voltages. The game boots and goes into attract. I play a game, (works correctly), get killed and enter my initals. The following, (second) attract is messed up. Letters are missing from words, the score is missing numbers and the dividing red lines that seperate the various areas of the display are missing in areas.

The display is not all jumbled up and skewed etc. Just some information is "missing".

I shut the game off for 10 seconds and reboot, then when I press the one or two player buttons, it puts credits on the game. I have to flip the credit switch to start a game.

This is not the situation when the game is "cold", the credit and start buttons function as they should.

I pulled the switcher that someone hacked into the game and installed a fully rebuilt Sega linear power supply. I had to also replace the hacked wires in the harness. And then while the harness was out, repinned them all with Trifurcon pins to insure a proper connection.

I set the voltage a little on the high side, +5.12 but that did not help either.

Also, there is much oxidation on the board cage, spinner encoder wheel and the CP hardware, it's like hair is growing all over the place, (I'll post those pics later on).

I pulled all the boards and happy to say that they were not corroded. I reseated all the socketed IC's on the CPU and ROM PCB's but still have the same issues. Since the speech, sounds and drawing work, I think that the problem is either on the CPU or ROM PCB's.
Am I going in the right direction?

I'll video the situation and post a link later as well.

ANY positive suggestions would be greatly appreciated.

Thanks in advance.
Jeff

Check the +5 volts at the chips.
 
I had verified voltage at the cage which is at +5.12vdc and I probed the EPROM PCB which read +5.07vdc. I did that one as it had the most IC's and would have the biggest draw.

I preformed the internal test and it seems that all is OK but that is not the fact.

I get:
-All video RAMs good
-Multipliers good
-P1 and P2 activate as I press the button
-Color bars come up
-All ROMs good
-Options switched list but when I flick the credit switch the screen changes, like I hit the P1 button
-Then I get the screen with Fire, Thrust, Photons, Warp and Spinner, which all activate

I am going to sound out the harness. Maybe the same "guy" that hacked the P/S screwed with the harness for some reason......

BTW, here are the pics of the cage and spinner etc....

What would cause this?

Jeff
 

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That IS odd.

Is that the point that it always messes up? At the attract mode after a full game?

If so, I'd think that something is up with the program RAM or the EPROMS. After it wigs out, does the reset button inside the coin door straighten it back out, or does it require the full power cycle?
 
It does not "wig out", just some missing text.

If I play a couple of quick test games, just die as soon as possible, the attract works always, until it gets "hot" then the missing text starts.

The 1 and 2 player start buttons always put credits on the game and if I press the 1 or 2 player really quickly, then it will start a game. The credit switch on the coin door, once there is credits on the game, will always start a game!

I checked the harness from the CP and it is not hacked. I am going to pull the manual and see if I can track this down - really weird!

BTW, either pulling the plug or resetting from inside the cab has the same results.

Jeff
 
It seems like somethings happening when it gets hot. Ive read alot of people on here getting results using that cold spray.Why not try spraying on the rams while they are hot and see if theres any change.
 
Have you tried swapping the order of the (6) game boards in the cage? Have you cleaned the cage and the edge connectors on the boards? (Would be nice if it is a simple a fix as that, huh!)

If you have any other KLOVer that lives nearby that would be willing to loan you a boardset, then it would just be a process of elimination - swap each one of the boards in until the error stops - then you can isolate the board (if that -IS- the problem)

You are dealing with one of the most touchy arcade games - Star Trek SOS are difficult to keep running.

Keep us posted on your progress!
 
It seems like somethings happening when it gets hot. Ive read alot of people on here getting results using that cold spray.Why not try spraying on the rams while they are hot and see if theres any change.

That is a very good idea I would do that if I could find a way to get to the boards while the game is running. Being that the cards are in that cage, I cannot shoot an IC without hitting all the others but I guess it would isolate the problem to a specific board.....
 
Have you tried swapping the order of the (6) game boards in the cage? Have you cleaned the cage and the edge connectors on the boards? (Would be nice if it is a simple a fix as that, huh!)

If you have any other KLOVer that lives nearby that would be willing to loan you a boardset, then it would just be a process of elimination - swap each one of the boards in until the error stops - then you can isolate the board (if that -IS- the problem)

You are dealing with one of the most touchy arcade games - Star Trek SOS are difficult to keep running.

Keep us posted on your progress!

I was very very relieved to find that the corrosion was local to the exterior of the cage, the interior is clean.

The edge connectors are clean and bright but now that you mentioned it, I'll get the eraser out and give it a once over just to be sure.

I do have another boardset, condition unknown, I'll just have to find it first. It won't hurt to try and swap some boards, I just might get lucky.

The swapped credit and start make me think the the problem lies somewhere on the CPU card.....

Thanks for all the suggestions, hopefully I'll get this bugger!

Jeff
 
The missing characters and line segments only occur after you play a game or is it after a period of time that the game has been on?

If both problems are not apparent on a cold start up, then it would appear that PCB components that draw more power during game play and heat up as a result may be the culprits.

The weird thing is that it sounds like to two unrelated issues, but related at the same time. A rom and CPU problem wouldn't seem to have anything in common unless it involved the connections.

Did you swap the position of the cards inside the cage? Or checked for a metal shaving wedged somewhere that would cross the credit switch and player one signals? (Stupid, I know). I assume you checked for bridged or cold joints on the PCBs. And I'm assuming the previous owner experienced no such problems.

I'm very interested in your resolution, because I have Dedicated Star Trek gathering dust that I've started looking into.

Darren Harris
Staten Island, New York.
 
I am going to start mixing an matching PCB's with another cage set I have and with any luck, I will discover which board is giving me trouble, hopefully it's only one........
 
This is a pretty common problem with this game. I have it happen intermittently but when it does happen it's after the game has warmed up. Reseating the boards has helped in the past but it always seems to come back. FWIW, I have a hacked in switcher to mine as well.

I have always thought that maybe installing another fan to blow into the cage might help. I also thought that maybe it has something to do with cold solder in the cage. I've noticed that the solder on the PCB holders/connectors gets very very crusty on these.
 
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