Gorf Repairs

Mizzou

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So I got this gorf on the cheap and figured I would start trying to learn to fix my own games rather then always having to get people from the forums to come over and help me do it.

Step 1. Plugged her in...nothing. Checked the fuses on the power brick and found one had blown.

Step 2. After replacing the fuse I turn it on again..no loud boom! ..so thats good. However, its giving me a static screen and then it will flash on and off at me..My next guess is to look at the power supply and see what kind of voltage I am getting..Problem..I have absolutely no idea how to do that. Its not a switcher, its the original williams, but I dont know where the test points are on there..Could someone lend a total noob a hand and maybe point me to an illustration or a nice how to on this? Also if there are any other ideas on what to look for with the gorf please let me know..Thanks!
 
Those linear power supplies can cause issues. AFAIK, there is a rebuild kit out there if youre somewhat-handy with soldering.

Also, you might just try reseating all the connections you can find, along with reseating all the cards in the board stack. You never know!
 
Ill give that a try, I actually hace a midway power supply. Ill have to see if it is the same seriesas the one I have in my tron and spy hunter.. I still need to learn how to check the voltage though..can anyone suggest a good link or something?
 
yeah, but for whatever reason I cant get the images to appear..it just shows a small box with an x in it..Any ideas how on what I can do there?
 
It does not use the same power supply as tron (90412). Pull the header connectors off the power supply and look for burnt connections. There is a yellow wire on it that is almost always burned up.
This is not a good game to learn repairs on.
 
Yeah gorf sucks to work on. Riptor is right on, that power supply connector is usually toast.. if your not tech savy get the arcade shop supply. You almost need a fully working set to debug these...
 
Yes, 1 of the 2 yellow wires/connector housing/board header pin (or all 3) at position 1 and 2 is usually crispy (do a search here for all GORF threads that have pics of the PS, you'll see it). However one of these lines is redundant, so even if the other is still connected, that's not your problem.
 
The best location to test voltages is at the small molex that is connected to the bottom of the pcb cage. Sorry I dont know the pinouts right now, but it should be easy enough to find by trial and error, or download the owners manual. But as others have stated even if you power is good, there are so many things with Gorf that can go wrong that is only one of your issues. The ram cards can have issues, as well as the cpu board especially. If you don't have a heatsink on your cpu board it's most likely done for...
 
i rebuilt my gorf power supply with the kit from bob roberts and it works great, all the voltages adjust spot on. as above the connector that goes to the bottom of the board cage is the best place to test the voltages. under the pins unless its covered in dust tells you what the pins are 5v,5v, 12v ect. start by testing those and adjust the pots if the voltages aren't right. i wouldn't plug the board cage in until you have checked the voltages are right.

if you can solder its a nice job rebuilding the original power supply and much nicer to keep the machine original instead of fitting a switcher.

you also need to download the manuals for gorf and the wiring diagrams will come in really handy. ive replaced almost every pin in all the connectors for mine.
 
Yes, the card rack pcb power connecter is labeled right on the pcb. When I set the 5v I usually measure off an IC a card in the rear of the rack. You will find there is significant power drop across the boardset.
For what its worth, I installed a switcher in mine and kept all the wiring intact. I just wired up pigtails soldered to headers that plug into the original harness.
 
That sounds a good way to do it. I thought it a good idea to check the voltages to get an idea before putting an unknown voltage through a boardset. Then check from an ic like you say and maybe turn it up a little if needed.
 
Yes, the card rack pcb power connecter is labeled right on the pcb. When I set the 5v I usually measure off an IC a card in the rear of the rack. You will find there is significant power drop across the boardset.
For what its worth, I installed a switcher in mine and kept all the wiring intact. I just wired up pigtails soldered to headers that plug into the original harness.

Done this myself. Ive found that some boards are more sensitive to the reset line timing. A few would need to be reset after powering up to run.
 
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