Star Trek SOS won't boot.

[SaminVA]

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

(And has anyone accomplished that before?).

Darren Harris
Staten Island, New York.

What do you mean by G80 ?
All 3 Star Treks are G80 games
I supose I could get a Star Trek in a convert a cabinet.
Not sure thay made a Star Trek in a cocktail or not but they did make the 4 player Elminator, that would be cool

 

[D_Harris]

What do you mean by G80 ?
All 3 Star Treks are G80 games
I supose I could get a Star Trek in a convert a cabinet.
Not sure thay made a Star Trek in a cocktail or not but they did make the 4 player Elminator, that would be cool

Yes, the G-80 Convert-A-Cab.

It would be great to see a pic of all four together.

Darren Harris
Staten Island, New York

 

[Sinistar]

Oh you guys don't know how baddd I want this game working, it is sitting there teasing me and hearing a quick fix like a chip replacement working has me all the more determined to get this sucker working.

The story so far,

monitor works as far as I can tell- Ive tested HV and can hear it power up.
Ive tested all the power going into the g80 cage and it all checks out good, but I can see no LED on the cpu board,
hear nothing (although i can hear a sound pop if i plug the g80 power conector in),
and the reset switch does nothing.
History is that it worked fine one day, and stopped the next (a few yrs ago).

I see no way of taking the g80 cage apart for testing purposes, no way to easily reach that z80 down there to test its clock. If someone has some suggestions that'd, be great.

I still need to pull all the chips for cleaning, but i dont have an eprom reader yet to go any further than that.

I can say Ive isolated it to the cpu, pre-boot, pre-test, but that where Im stuck.

Im going to clean that cpu board thoroughly tonight, and will report back asap. This is probably one of my favorite games of all time, and its just eating me up seeing her sit there!!

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.

 

[SaminVA]

Oh you guys don't know how baddd I want this game working, it is sitting there teasing me and hearing a quick fix like a chip replacement working has me all the more determined to get this sucker working.

The story so far,

monitor works as far as I can tell- Ive tested HV and can hear it power up.
Ive tested all the power going into the g80 cage and it all checks out good, but I can see no LED on the cpu board,
hear nothing (although i can hear a sound pop if i plug the g80 power conector in),
and the reset switch does nothing.
History is that it worked fine one day, and stopped the next (a few yrs ago).

I see no way of taking the g80 cage apart for testing purposes, no way to easily reach that z80 down there to test its clock. If someone has some suggestions that'd, be great.

I still need to pull all the chips for cleaning, but i dont have an eprom reader yet to go any further than that.

I can say Ive isolated it to the cpu, pre-boot, pre-test, but that where Im stuck.

Im going to clean that cpu board thoroughly tonight, and will report back asap. This is probably one of my favorite games of all time, and its just eating me up seeing her sit there!!

They make a card extension which slides in one of the slots and has a edge connector on top so you can plug the board in on top of the cage for testing a board but they are as scarce as hen's teeth. I have only seen pictures of one. What you can try is take the back pane out of the cage, held in with 4 screws and plug the 2 x,y boards and the CPU in, lay it on the side and maybe put foam between the boards to keep them separated and straight in the card slots. Never tried it but sounds like it might work. You could also try and find a working CPU or send it off to someone to be fixed but I don't know who works on these now. Maybe someone can chime in if they know.

 

[Sinistar]

Maybe someone can chime in if they know.

Heck I'd just appreciate if one of you fellas would take and do some chip swapping for me if I get truly stuck. I still have a lil more tinkering to do, but if I had a working one sitting here- man things sure would go alot smoother. I've heard mention of a Mongo who can fix these- so I might try him too. I have got to get this thing working!


Thanks for the help all!

 

[Muel]

I'd be happy to help. First, I would agree with you in your assessment tho ...that there is a problem in the boot stage.
2 things come to mind that you can try, that are not to expensive either...

1. Buy a NEW z80a CPU ($2 at JAMECO.com)
2. Buy (4) NEW 2114 RAM chips (also $2ea at JAMECO.com)

Maybe the z80a that you swapped with another game of yours - the PCB just didn't like... or maybe the CPU still wasn't making contact with all of the socket connectors? The NEW z80a CPU that I bought fit TIGHT in the socket as with NEW chips, you sometimes have to 'roll the pins' on the chip to get it to go in the socket. I could't believe my ears when I heard the Star Trek music bellow thru the basement once again! Something as simple as a $2 CPU kept it dead in the dark for so many years...

Also, while I had the PCB out of the cage, I gave it a good general cleaning and I cleaned the GOLD edge connector contacts with a SOFT eraser. It is also possible that your card is not making good contact with its edge connector. Try and shift this card over 1 socket in the cage (you may have to move other cards to make it work - the slots are not specific to any card)

I have my fingers crossed for you!!!

-Muel

 

[Sinistar]

Well, I cleaned that board good last night, and nothing popped for me. Im going to order all new rams and a Z80 and see what cooks. Stand by for parts order.

 

[Muel]

Bump for update..

So Sinistar, did you get the Z80a and ram chips?
Is the Star Trek alive once again?

Just curious if you have had any progress...

 

[Sinistar]

About to make some progress, at least I sure hope so- as I just bought the tested/working set off of Perfidious. Ill use that set to diagnose this one- then release one back into the wild Muuust play Star Trek.....

 

[Muel]

I can totally understand the fever to play Star Trek once again. Sounds like you are on the right track to diagnosing your bad board(s). Good luck and keep us posted on what you find out!

 

[Sinistar]

Update:

So I received a set of tested working boards and they didnt boot either. Expensive test, uggh.

So doubling back to the power supply my readings off of the power cable are as follows
Power
-12.2
11.8
cycles between -3.58 and 5.26
G
G
G
-5.05
0.348
0.350
0.350


So is this not good with not getting a full 12 and +5 cycling to -3?

 

[Muel]

Yea, it looks like that your 5v is off:
Pinout on the P4 connector should read:

(1) Orange -12v
(2) Red +12v
(3) White AC
(4) Black GND
(5) Black GND
(6) Black GND
(7) Violet -5v
(8) Brown +5v
(9) Brown +5v
(10) Brown +5v

Set yout MM for AC on pin 3

But you are missing +5v which is essential!

Recheck your fuses inside the PS just to be sure...

Time for a PS rebuild most likely...

 

[Sinistar]

Ummm yeah... The 32v fuse was blown. Don't I feel dumb. I post my shame here in hopes of saving someone some future grief.


So 32v fuse, can I get that at auto zone or is it special?

 

[SaminVA]

Ummm yeah... The 32v fuse was blown. Don't I feel dumb. I post my shame here in hopes of saving someone some future grief.


So 32v fuse, can I get that at auto zone or is it special?

As listed in the manual
F1,F2 - 3 amp normal fuse
F3 - 10 amp Slow Blow fuse
F4 - 1.5 amp normal fuse
It doesn't matter what voltage, could be 250 volts but the amperage ,type, slow blow or normal and they have to be the correct size too.
Try a new fuse and re check the voltage before plugging the new boards back in. If the fuse blows again then rebuild the power supply.

 

[Muel]

I totally agree with Sam... check voltages again, especially before putting in known working boards!

Keep in mind, there must've been a reason why the fuse blew in the 1st place!

Sounds like you're on the right track to getting this ST up and running.

 

[Sinistar]

Alright so replaced the fuse, it didnt blow but I'm getting really high readings now.
Starting at orange:
22.1
22.1
17.7
22.2
22.3
22.3
22.4
22.1
22.0
22.0

No ground at all And high everywhere else.

I see an adjustment knob in there but would it really fix this?

 

[Sinistar]

And if rebuilding the power supply is the answer, where can one pickup a rebuild kit from?

 

[SaminVA]

Alright so replaced the fuse, it didnt blow but I'm getting really high readings now.
Starting at orange:
22.1
22.1
17.7
22.2
22.3
22.3
22.4
22.1
22.0
22.0

No ground at all And high everywhere else.

I see an adjustment knob in there but would it really fix this?

That doesn't look right. Replacing one fuse should not affect all your readings. Are you sure you measured the voltages correctly?
I don't think anyone sells a rebuild kit so you will have to put it together your self.
Here's a good web site to get started.
I think most of his part numbers are from Digikey but you can find them at most good electronics parts stores. NO not Radio Shack
http://www.biltronix.com/Star_Trek_08.html
Another option would be to buy a working power supply from someone or find someone who could rebuild it for you.

 

[kstillin]

That last set of readings is pretty whacked.

These G80 power supplies are pretty straightforward. All I've ever seen them need is fuses and individual regulators or diodes. Sometimes the headers are messed up from somebody soldering directly to them or something.

 

[Muel]

Yea, I'd say that's a bit off... way off...

You must have a blown regulator or diode - something's shorted out. ...which would've caused the fuse to blow in the first place.

Don't let those voltages pass thru to the board set!!!

On the PS, if you are going to replace the caps, there is an issue with (I think 5) of the large caps. You have to drill into the PS board and make 5 new solder points since the new caps won't line up with the original holes. There is instruction on how to do just that if you are checking out the previous posters web links. I doubt that your problem lies with the caps tho... If you have the PS out, look for the obvious signs of burnt parts, including the header pins - if they are burnt, replace the pins.

Alright so replaced the fuse, it didnt blow but I'm getting really high readings now.
Starting at orange:
22.1
22.1
17.7
22.2
22.3
22.3
22.4
22.1
22.0
22.0

No ground at all And high everywhere else.

I see an adjustment knob in there but would it really fix this?