Gorf Repair Guys, Help

Phetishboy

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OK, I restored a working GORF machine. I was putting the finishing touches on it when I noticed frayed wires near the larger edge connector that plugs into the IO board. I turned the machine off, got out some heat shrink tubing and connected/ covered the bare wires. Turned it back on, the game played blind. I tried reseating, removing, etc and still the same. Game played blind. Sent my RGB board, full wiring harness and IO board out for repair. All 3 were tested/working and new connectors were crimped on. Got them all back, plugged them in, still playing blind. Monitor was lit up yellow, sounds could be heard in attract mode. Sent all 5 boards out for repair, all 5 were tested and working. Decided to rebuild my power supply board. got it all rebuilt, unpacked my board stack, plugged it all in and now it no longer even plays blind. Monitor powers up, lights all power up, no video, no game sounds. The only hitch I had when rebuilding the power supply, is that smaller voltage regulator's legs were too damned short to poke thru the board when the screw on the heatsink was in place. I just melted more solder into the holes, and with the middle leg, I actually had to add a clipped capacitor leg to bridge the distance of less than half a millimeter.

My question is, where should I be testing voltages and what should I be getting?

My second question is, could the tranformer/ power brick be bad? The AC for the lights and monitor seems fine.

My 3rd question is, if all else fails, can I get someone to take a look at my power board/ 5 board stack and RGB board and see if they all work together in another working machine? I can send them all to someone in a flat rate box.

Signed,

Fucking Baffled
 
I don't have the manual, but thanks. I guess I can try to open those slow assed PDF's on arcarc.

OK, you've been collecting, restoring and repairing arcade games for how long now? The *first* thing you should always do is download the manual. Go to CrazyKong, or arcarc, or whatever - all the common games are out there, and you can have the manual within two minutes. If that's too slow for you, then...

But seriously - don't just throw parts at a game without stopping to figure out *why* it's not working. You'll drive yourself nuts, as you already have, I see :D

Yeah, I'm giving you a hard time, but you've been in this hobby for a long time. No excuse not to have the manual. Heck, I usually read the manual before I've even picked up the game.

-Ian
 
OK, you've been collecting, restoring and repairing arcade games for how long now? The *first* thing you should always do is download the manual. Go to CrazyKong, or arcarc, or whatever - all the common games are out there, and you can have the manual within two minutes. If that's too slow for you, then...

But seriously - don't just throw parts at a game without stopping to figure out *why* it's not working. You'll drive yourself nuts, as you already have, I see :D

Yeah, I'm giving you a hard time, but you've been in this hobby for a long time. No excuse not to have the manual. Heck, I usually read the manual before I've even picked up the game.

-Ian

I'm more of a restoration guy. Beyond capping monitors and owning a multi-meter I am lost on the electronic side of things, even with a manual. I'll leave that part of it to you fine fellows with the temp controlled soldering stations, the O-scopes, the logic probes and the eprom burners. I had Rip helping me out, but he is in the middle of rebuilding his work space and has no time for repairs at the moment. This thing was working when the restoration of the cabinet was finished, now it's not. 90% of the components test out as working in another person's machine. The only 2 things that have not been tested are the power brick and the power supply board. I have 13 restorations to do, and just have no more time to screw with this one if I wanna get at least half of the other 13 done by the time my 3rd kid is here. In addition, I also have a Tempest to troubleshoot, my Pole Position is down and my recently restored Multi-Williams is still not working right. Forgive me if I seem a little frazzled at this point. I wish I had hours of 'shop time' but I just don't anymore.

Signed,

Mr. Saddy Pants
 
Forgive me if I seem a little frazzled at this point. I wish I had hours of 'shop time' but I just don't anymore.

Signed,

Mr. Saddy Pants

Hehe. I'm just giving you a hard time.

One thing I would double check is the connector from the power transformer that plugs into the power supply board. On every GORF I've worked on, this has been crispy and burnt.

Also, the power connector that plugs into the backplane gets flakey too, I've had to replace those as well. Check the voltage both at the power supply, and at the backplane's power connector (the backplane is labelled, IIRC)

-Ian
 
I struggled with my Gorf for a LONG time.

After swapping boards from 2 spare sets and rebuilding the PS I got it running for a while.
Then I had similar issues as yours. It would seem to always need tinkering to get it to play.
I eventually wired in a switching PS but the problems came back.
I decided to pull the switcher, and I replaced all the connectors, and used the cleanest card cage of the 3 I had. It has worked fine ever since.

There's so many connections from board to board on Gorf. That's where I'd focus.

Good luck
 
I struggled with my Gorf for a LONG time.

After swapping boards from 2 spare sets and rebuilding the PS I got it running for a while.
Then I had similar issues as yours. It would seem to always need tinkering to get it to play.
I eventually wired in a switching PS but the problems came back.
I decided to pull the switcher, and I replaced all the connectors, and used the cleanest card cage of the 3 I had. It has worked fine ever since.

There's so many connections from board to board on Gorf. That's where I'd focus.

Good luck

Yeah, I will get out the meter and start checking things. The connectors have mostly been replaced, but the one that plugs into the power supply board and the one that plugs into the bottom of the board cage have not been. I will start there. Thanks.
 
I'm more of a restoration guy. Beyond capping monitors and owning a multi-meter I am lost on the electronic side of things, even with a manual. I'll leave that part of it to you fine fellows with the temp controlled soldering stations, the O-scopes, the logic probes and the eprom burners.
I feel the opposite way myself. Now granted I'm no genius at all with the electronics repair side of the hobby, but it's definitely the half that I gravitate towards. I'm just not very skilled yet (hopefully at some point I will be) with woodwork. I suppose the only way to get better is to dive in and learn by experience.
 
First thing, let's make sure the power supply is working. Undo the four 1/4" hex screws that secure the board cage to the bottom of the cabinet. Set the board cage on the floor behind the game. Plug the power connector back in....you might have to unscrew a cable clamp or two, to give enough slack for the harness to reach outside of thhe cabinet. Fire it up and measure the voltage at this plug. The board is printed with the voltages on it. Do you have all voltages? Report back. Don't forget to check the pin labeled "reset". Also, check for DC voltage across the 4700uf25V cap on the power supply board. This is the audio voltage. Without this juice.....no sound.

You can obviously do all this inside the cabinet, but it's a hell of a lot easier to spend 3 minutes and pull everything outside the cabinet.

Edward
 
First thing, let's make sure the power supply is working. Undo the four 1/4" hex screws that secure the board cage to the bottom of the cabinet. Set the board cage on the floor behind the game. Plug the power connector back in....you might have to unscrew a cable clamp or two, to give enough slack for the harness to reach outside of thhe cabinet. Fire it up and measure the voltage at this plug. The board is printed with the voltages on it. Do you have all voltages? Report back. Don't forget to check the pin labeled "reset". Also, check for DC voltage across the 4700uf25V cap on the power supply board. This is the audio voltage. Without this juice.....no sound.

You can obviously do all this inside the cabinet, but it's a hell of a lot easier to spend 3 minutes and pull everything outside the cabinet.

Edward

That is exactly what I was going to do. Nothing is secured in the cab at this point, as I just reinstalled it all. Funny you popped up, I was just about to PM you to see if you'd let me send this power supply board to you to see if the rebuild I did worked, or If I screwed something up.
 
That is exactly what I was going to do. Nothing is secured in the cab at this point, as I just reinstalled it all. Funny you popped up, I was just about to PM you to see if you'd let me send this power supply board to you to see if the rebuild I did worked, or If I screwed something up.

You can send me anything you like, for testing;)....but I think we can narrow a lot of this down through posts, PM's, whatnot.

If not already done....check the backside of the connector headers on the power supply board and the input connector header on the cage for cracked solder. Reflow if needed.

Edward
 
OK, this is kinda weird, I tested the pins in the connector that plugs into the bottom of the board stack. With it unplugged, I get 5.09V on the 5V lines and reset line, -4.86 on the -5V line. When I plug it into the board stack and meter, I get .86 on the 5V lines and -0 on the -5V line. When I test the points coming out of the IO board, I get .84 on the 5V lines I was able to test. What's up with the voltage drop when it's plugged in vs. unplugged?
 
OK, this is kinda weird, I tested the pins in the connector that plugs into the bottom of the board stack. With it unplugged, I get 5.09V on the 5V lines and reset line, -4.86 on the -5V line. When I plug it into the board stack and meter, I get .86 on the 5V lines and -0 on the -5V line. When I test the points coming out of the IO board, I get .84 on the 5V lines I was able to test. What's up with the voltage drop when it's plugged in vs. unplugged?

Well, this is where it gets tricky. One of two things is happening......something is shorted on the motherboard stack, pulling the voltage down..........or, something is marginal on the power supply board, crapping out under load. What's odd in your situation, you've got two separate voltage lines dropping.

Do you have another game that uses this same power supply, you could toss it in for testing? If you've got a switcher around, you could alligator clip it to the ground, 5VDC, and -5VDC points at the motherboard connector.....see if the switcher shuts down....or not.

Edward
 
Well, this is where it gets tricky. One of two things is happening......something is shorted on the motherboard stack, pulling the voltage down..........or, something is marginal on the power supply board, crapping out under load. What's odd in your situation, you've got two separate voltage lines dropping.

Do you have another game that uses this same power supply, you could toss it in for testing? If you've got a switcher around, you could alligator clip it to the ground, 5VDC, and -5VDC points at the motherboard connector.....see if the switcher shuts down....or not.

Edward

I don't have another game that uses this power supply. If you can test this for me, I'd be happy to send it out. I can send the board-stack as well, to make sure the problem gets isolated. I'll send the RGB board too. I'll compensate you for your time of course. I would rather someone with experience in this sorta thing takes a look at it with a decent test bench. I was lucky to get the little time I had yesterday to even test voltages on the darned thing. LMK if that works and PM me your shipping address if it does. Preciate it,

Phetty Green
 
Pull the RAM cards out and try again, see if the voltage stays up. I've seen the tantalum bypass cap fail on those RAM boards and do just that.

-Ian
 
Both of them?

Yeah. The game won't work without them, but you can see if that stops the voltage from dropping out. If it does, put one in, try it, then the other, etc.

But, since you say you've tested all the parts elsewhere, it seems unlikely you have a short, but, still - always good to check. It's just that I had this exact problem when I had a shorted tantalum on a RAM board. It only took out the +5 in my case, but there is a cap across each of the voltage legs, so two failed could do this.

-Ian
 
These boards were just tested on my bench and worked great. I doubt its a board problem. Why dont you install a switcher and be done with it.
 
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