Star Trek SOS won't boot.

Muel

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Hello..

I'm hoping that someone out there is familiar with the old Star Trek SOS game.

I have a "captain's chair" version of this game. I bought it many years ago - originally working after I got it home - for many years after that as well.
One day, it just decided that it didn't want to boot anymore.

Here's what I've come to find out so far....

Game partly powers up- coin doors light, Power supply puts out power - not getting any sound or video though.

I did test the power supply and it is putting out +5 (5.05 each to be exact) and the 12v is spot on. The CPU board that has the "test" button on it has a LED just below it. I assume that when the boards are powered that this LED should be lit - it is not. "Test" button on board does nothing, reset switch near volume does nothing. Main power fuse is good. I also checked Power Supply Fuses.

Is the CPU board dead? I checked all 6 boards for obvious signs of burnt components and all looks good, traces look good..

Any thoughts?

Thanks,
Muel
 
First thing you need is the manual, if you don't have one make sure you get the one for your game. They made 3 different manuals, Cockpit, dedicated upright and kit versions. For the most part they are the same but have slight differences in the wiring harness and cabinet parts list. They have a lot of trouble shooting info as well as schematics, wiring diagrams and parts lists.
Next download or print a copy of The Sega/Gremlin X-Y FAQ version 1.15 written by: Mark Jenison
you can find it on his web site
http://users.rcn.com/jenison/mars/
First unplug the power going to the monitor and the signal wires too. No need to risk the monitor if it's good if you have a power supply or board problem.
Start with the power supply, theirs more than +5volts and +12volts
You have +5VDC, -5VDC, +12VDC, and -12VDC
You have 4 fuses inside the power supply. Did you take the metal cover off and check them?
The audio amp is also made into the power supply.
Once you have all the voltages then you start with the CPU board. Here's what Marks Sega/Gremlin X-Y FAQ says to do.
"CPU boards
==========

The led on a good CPU board will flash out information that can be used to
debug other problems; check the manual for these codes.

If the game isn't coming up, press the test plunger. If you get a halt light,
try replacing the 2114 RAMs and replacing the Z80 CPU and see if that fixes it.
If the halt light flashes repeatedly, the first 1k of EPROMs is either bad or
making a bad connection. If you get nothing, the CPU is bad (or the LED or
test switch is bad).

By the way, bad sound boards and speech boards can cause symptoms that might
make you suspect the CPU or X-Y boards are bad. Do not test CPU and
X-Y boards with untested sound and speech boards. You don't need these boards
in the card cage for the game to run, so unplug them and set them
aside until you've tested the rest of the boards."

If I had to guess I'll bet you have a power supply problem so check it out first.
The plug and pins on the AC input of the power supply often over heat and burn up and turn brown or black and the pins can have bad solder joints on the power supply board too.
 
Hey Sam!

Thanks for replying back.

Okay, I checked the voltages coming off the Power Supply Harness at the bottom of the card cage - got +5.05, -5.05, +12, -12 - I had previosly opened the Power Supply and fuses were good. AC input looked fine, no burnt pins or connectors.

I will remove the other unnecessary boards (sound and speech) and retest to see what happens with the CPU PCB.

Currently, no LED will light (at all) or flash codes, test button does nothing either. If the z80 is bad, would that make the board act totally dead?
 
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Hey Sam!

Thanks for replying back.

Okay, I checked the voltages coming off the Power Supply Harness at the bottom of the card cage - got +5.05, -5.05, +12, -12 - I had previosly opened the Power Supply and fuses were good. AC input looked fine, no burnt pins or connectors.

I will remove the other unnecessary boards (sound and speech) and retest to see what happens with the CPU PCB.

Currently, no LED will light (at all) or flash codes, test button does nothing either. If the z80 is bad, would that make the board act totally dead?

Yes if the Z80A is bad everything will be dead.
You could try removing the Z80A and cleaning the pins.
Even install it in another game if you have one that uses the Z80A, like Asteroids or Pac Man or even Frogger I think or just put in a new Z80A if you have one.
Also remove the 4 RAM chips and clean the legs and put them back in.
According to the manual,First is the CPU RAM test- Test all RAM on CPU card before proceeding,system needs to use this RAM for stack and Variables during other tests so if any locations are bad processor will half(halt light will come on)
Also check the card slots and bottom of card edge. They should be clean. Sometimes dust and dirt can fall in the card slots in the bottom of the cage. Some times just plugging the cards in and out can make things work again.
It's always easer to find a working set of boards and swap in the non working set one at a time to find the bad board.
If you put a know working board set in and it's still dead then you know the card cage or wiring or power supply is the problem.
I am sure their is someone here that knows someone that works on these boards.
Hopefully someone will chime in if none of this works.
 
Okay, I think my next stop will be the Z80A. I had already cleaned the bottom of the cage - yes, it was way dusty! I had removed all the boards (carefully noting the positions of all the connectors on top and where they go as well.) I vacuumed all the dust out of the box and it is super clean. I'll try and clean the pins on the Z80A and reseat it in the socket as well as the 4 ram chips. If I get no love there, I'll try and replace the Z80A with a new one - a trip to FRY'S Electronics!

Question, if the Power Supply put out more voltage than the 5 and 12 to the PCBs, would it have damaged the CPU board or the CPU itself? I know that our city power has varied over the years from 115v to as much as 130v which would step up the transformer going to the Power Supply. I'm beginning to suspect that at one point, this could have been the case.
 
Dont forget that the first device that the Z80 reads on reset is the EPROM on the CPU board... the RAM test program is in that EPROM. No EPROM, no test. So be sure to check that as well... There are others that will affect boot such as the security chip, which all addressing goes thru.

Troubleshooting G80 with guesswork is a bitch because how the cards are in the cage... Its easiest to have a spare, known good set to isolate the bad card...
 
If I were to swap the g80 CPU board with one from like Space Fury - is it a direct swap or does the "Star Trek" eprom need to be swapped to the new board?

I'm gonna try and take the board out and clean it up a bit. Gonna try and check the test switch for continuity and see if it is functioning properly. If the switch is bad, I imagine that it could also keep it from booting.

You're right, those PCBs and cables are packed tight. Not very easy to work on unless you undo the connectors. Leave the ribbon on xy-boards tho. Wish me luck.
 
Yes the CPU boards are the same and the security chip 315-0064 is the same for both Star Trek and Space Fury so you wont have to change it but you will have to change the one EPROM chip on the board. Star Trek EPROM is 1873 and Space Furry is 969,
 
Thanks for the reply back SaminVA (and thank you armis2000 for your input as well!)
Okay, I took out the CPU board and checked the "test" switch and it still works fine, checked with the meter and it's not stuck.
I took out all the socketed chips on the CPU board, cleaned the pins and re-seated them (ram, Z80a, eprom)
I cleaned the gold contacts at the end of the PCB just to make sure that it is getting a good connection.
I plugged the board back in - still no LED.

I know that the PSU connector is putting out the right voltages at the end of the connector... however...
Is there a place on the CPU board that I can test to make sure that the board itself is getting +5v ??

I think I may pull all the boards and test the slots to see if they are getting +5, -5, +12, -12 volts. I'm not sure witch one is the 3vac tho...

If I get juice at the slots, I will go and get a z80a chip and 4 ram chips for the CPU PCB and replace them. Again, I did not see any fried components on the CPU board upon visual inpection.

BTW... I went to your webpage Sam - I love your arcade (and your restorations!) ....and I cannot believe that you have (3) Star Trek SOS games!
 
similar issues

Is it okay if I jump aboard this thread? Seems were trackin similar issues.

I just acquired a dedicated upright, with dead boards and no led. Monitor appears to be ok, Power Supply ok. Previous owner says worked one day and then just stopped. Very clean cabinet all around, interior as clean as the exterior- home owned for 20yrs. $50 (!!)

repair log:
-fixed cut power cord
-Power running into the cage has been tested to be at correct voltages.
-no led flashes or any sign of life
-pulled all boards, looked for bad traces loose chips
-pull and clean socketed chips
-replaced z80a
-test without speech and sound boards

to do:
-test actual power to boards (how?)
-Test at TP points.

thats about it- I'll report back with anything else I do or find with my boards, and be watching this thread for any more details with you Muel:)
 
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Alright, so I just pulled the sound and speech boards, to test without. No good.
Pulled the z80 and replaced with a working ms pac z80a, and no good there. Still not seeing any led action of any kind.

What am I looking for at the various TP's on the board, and damn its really hard to reach the TPs down towards the bus with the cage on!

Any ideas what to check for next, what I think we're looking for here has to be high up in the boot chain.
 
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first to look at are: clock at the z80, and reset signal at the z80. clock should pulse, and reset should start low at power up, then go high...
 
ITS ALIVE!!

I got it working again.
Thank you everyone for your suggestions - it did the trick!

So, what was the problem?

A bad Z80A.. Yup!

I took the cue (from Armis2000 & SaminVA) about checking the Z80 and did just that. I live just 25 minutes from JAMECO so I went and bought a brand new Z80A over the counter for a whopping $2.25, popped that processor in and the room filled with that wonderful Star Trek music!

Led lights, test button works... back in business!

I did notice something new tho... The screen warps a bit (goes from small to big ~1" variance) when major vector changes occur, like completing a level an going to the next. Colors don't seem to be as crisp as they used to, in fact the playfield lines that separate the three sections are hardly visible. Any corrections that I can fiddle with or am I looking at a CAP kit?

-Muel
 
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ITS ALIVE!!

I got it working again.
Thank you everyone for your suggestions - it did the trick!

So, what was the problem?

A bad Z80A.. Yup!

I took the cue (from Armis2000 & SaminVA) about checking the Z80 and did just that. I live just 25 minutes from JAMECO so I went and bought a brand new Z80A over the counter for a whopping $2.25, popped that processor in and the room filled with that wonderful Star Trek music!

Led lights, test button works... back in business!

I did notice something new tho... The screen warps a bit (goes from small to big ~1" variance) when major vector changes occur, like completing a level an going to the next. Colors don't seem to be as crisp as they used to, in fact the playfield lines that separate the three sections are hardly visible. Any corrections that I can fiddle with or am I looking at a CAP kit?

-Muel

Yep, theirs not a sweeter sound than that Star Trek music when you flip the power switch.
Great work, glad it was as simple as replacing the Z80A.
As for the monitor, when it comes to the G08 unless it's got a very noticeable problem I tend to leave them bee. You might try turning up the brightness control a little, that may help. I have 3 Star Trek games working, one of them sense 1989-90 and it's still working great, knock on wood, so far none have ever caught fire. :004_scool:

Now if we can only get Sinistar's CPU running.
Sinistar, do you know if you have a working monitor? Ok just re read where it should be working.
Have you ever had this game working? Ok read that too.
If you replaced the Z80A with a known working one then you should check the Eprom chip at U25 should have 1873 on the label and the 4 Sram chips at U26,27,28,29 which are 2114 which I think are also found on a Pac man board.
If you can get the CPU running the test mode and your monitor works then it will tell you on the screen if any Roms or Rams are bad but I think the 1873 Rom at U25 has to be good and the only way to check it is with a Eprom burner/reader.
If you power the game and push the red test button on the CPU board do you see the red LED blink? If so look at the monitor to see if it comes up in test mode.
Also check and make sure it has the correct security chip installed in U21 it should have 315-0064 on the chip.
That's all I can think of for now.
 
Thanks for the reply back SaminVA (and thank you armis2000 for your input as well!)
Okay, I took out the CPU board and checked the "test" switch and it still works fine, checked with the meter and it's not stuck.
I took out all the socketed chips on the CPU board, cleaned the pins and re-seated them (ram, Z80a, eprom)
I cleaned the gold contacts at the end of the PCB just to make sure that it is getting a good connection.
I plugged the board back in - still no LED.

I know that the PSU connector is putting out the right voltages at the end of the connector... however...
Is there a place on the CPU board that I can test to make sure that the board itself is getting +5v ??

I think I may pull all the boards and test the slots to see if they are getting +5, -5, +12, -12 volts. I'm not sure witch one is the 3vac tho...

If I get juice at the slots, I will go and get a z80a chip and 4 ram chips for the CPU PCB and replace them. Again, I did not see any fried components on the CPU board upon visual inpection.

BTW... I went to your webpage Sam - I love your arcade (and your restorations!) ....and I cannot believe that you have (3) Star Trek SOS games!

Three Star Treks?!? Even I don't have three Star Treks. (But I've held the world record for 26 years). :D

I used to go to all the Star Trek conventions back in the 80s, so I guess you can call me a Trekkie. :D

I've been lazy and the dedicated one I have has been gathering dust for the last several years, so this thread has captured my interest.

Darren Harris
Staten Island, New York.
 
Three Star Treks?!? Even I don't have three Star Treks. (But I've held the world record for 26 years). :D

I used to go to all the Star Trek conventions back in the 80s, so I guess you can call me a Trekkie. :D

I've been lazy and the dedicated one I have has been gathering dust for the last several years, so this thread has captured my interest.

Darren Harris
Staten Island, New York.

yep 3 working. I just installed Vector Labs multi game in my Asteroids conversion which had one of Clay's kits installed. I supose it's time to update my web pages.
http://members.cox.net/sverlander/Star_Trek_Asteroids_conversion.html

http://members.cox.net/sverlander/Star_Trek_dedicated_page.html

http://members.cox.net/sverlander/startrekcockpit_page.html

Still looking for an orginial coin box for my cockpit.
 
SaminVA,

On your Captains Chair, the 110v fan on the back by the monitor, does it pull in air or push air out?

I've noticed that the fan on the Card Cage pulls the hot air out, and the fan under the seat also pulls air out of the box. However, the fan behind the monitor pulls air in...?? (I bought it from an arcade this way.)

I'm just curious how your monitor fan is set up?

If mine is installed backwards, it's an easy fix to flip it around.

I also agree on the monitor issue. I didn't want to have to mess with Caps. It's working, I'll just try and adjust the settings a bit to get the colors right. I had no idea that these monitors were even fire hazzards until I started researching about repairing the game itself.
Fire Extinguiser is now on hand.

On another note, have you found anyone making repros on the overlay for the 4-cluster of fire buttons? ..or sideart for the Captain's chair?

This is by far my favorite game and I would love to restore her (as best as I can) to her original glory.

-Muel
 
SaminVA,

On your Captains Chair, the 110v fan on the back by the monitor, does it pull in air or push air out?

I've noticed that the fan on the Card Cage pulls the hot air out, and the fan under the seat also pulls air out of the box. However, the fan behind the monitor pulls air in...?? (I bought it from an arcade this way.)

I'm just curious how your monitor fan is set up?

If mine is installed backwards, it's an easy fix to flip it around.

I also agree on the monitor issue. I didn't want to have to mess with Caps. It's working, I'll just try and adjust the settings a bit to get the colors right. I had no idea that these monitors were even fire hazzards until I started researching about repairing the game itself.
Fire Extinguiser is now on hand.

On another note, have you found anyone making repros on the overlay for the 4-cluster of fire buttons? ..or sideart for the Captain's chair?

This is by far my favorite game and I would love to restore her (as best as I can) to her original glory.

-Muel

As far as I remember the fan on the monitors all blow air into the heat sink tunnel to cool the 4 deflection transistors. Tomorrow I check that out.
I have never seen or heard of anyone making reproduction side art or arm control panel button plate for the cockpit.
My Captain's chair still had the original button overlay but it was badly worn,cracked into at the bend but the part under the buttons was intact with the 4 words so I scanned it and made a few on my ink jet printer. I printed it on adhesive backed vinyl and covered it with clear lamination stock. It should be very easy for someone to reproduce as it's white and the words are black. I still have my scans and the pieces of the original. Maybe we can find someone to reproduce these. Here's a sample of my scan

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yep 3 working. I just installed Vector Labs multi game in my Asteroids conversion which had one of Clay's kits installed. I supose it's time to update my web pages.

So when are you going to get the G80 to complete the set? :D

(And has anyone accomplished that before?).

Darren Harris
Staten Island, New York.
 
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