Queries with a Gorf PS...

keithsarcade

Well-known member
Joined
Nov 27, 2008
Messages
8,875
Reaction score
160
Location
St Peters, Missouri
Just brought a dead Gorf home, and I'm quick to suspect the PS board (A082-90411-B000). A couple caps look to have seen better days, and one of the chips has a leg not soldered to the PCB (maybe its supposed to be like that?).

Before I go poking at it with a meter, I am thinking I can use the PS from my Space Zap to quickly determine if this is indeed the culprit. They are very similar, only I'm noticing the Space Zap has a revision A PS (A082-90411-A000), and has a few less diodes and/or resistors (most noticeably on that chip I was referring to). Am I safe trying this out? I think so, but would like some confirmation before I try this.

First 4 photos are of the Gorf PS, last one is from my Space Zap.

Thanks in advance.
 

Attachments

  • gorfps1.jpg
    gorfps1.jpg
    96.4 KB · Views: 20
  • gorfps2.jpg
    gorfps2.jpg
    85.6 KB · Views: 14
  • gorfps3.jpg
    gorfps3.jpg
    82.4 KB · Views: 17
  • gorfps4.jpg
    gorfps4.jpg
    88.5 KB · Views: 15
  • szps1.jpg
    szps1.jpg
    89.9 KB · Views: 18
Those p/s usually have split caps. I highly recommend the Bob R kit. So it's around $20, but still cheaper than a nice switcher. Fix the original and you'll be ok.
 
Just brought a dead Gorf home, and I'm quick to suspect the PS board (A082-90411-B000). A couple caps look to have seen better days, and one of the chips has a leg not soldered to the PCB (maybe its supposed to be like that?).

Before I go poking at it with a meter, I am thinking I can use the PS from my Space Zap to quickly determine if this is indeed the culprit. They are very similar, only I'm noticing the Space Zap has a revision A PS (A082-90411-A000), and has a few less diodes and/or resistors (most noticeably on that chip I was referring to). Am I safe trying this out? I think so, but would like some confirmation before I try this.

First 4 photos are of the Gorf PS, last one is from my Space Zap.

Thanks in advance.

Those two power supplies are the same. The caps/resistors/etc on the chip of the Gorf power supply was hacked by someone. My guess.....that chip is part of the 5VDC regulation circuit....that chip is way obsolete.....it probably died....and you're looking at someone's attempt to fix it (this is all speculation).

Edward
 
Thanks for confirming. The swap didnt help. Space Zap still works with either board, Gorf doesnt. Problem must be elsewhere, maybe the boardset? Anyone know what fuse values are supposed to be in this game?
 
It lives! I swapped the CPU at J3 from Space Zap and got the screen below. So now I know this CPU is the culprit. I tried swapping Z80's just to rule that out, no difference.

Only problem is there is no sound either. Tried swapping amps with no difference. Sound works in Space Zap, so is it safe to assume another board is bad? Which board puts out sound?

Also, I'm noticing during play, my ship goes up on its own. Pulling down on the joystick will bring it back down, but letting go makes it go up again. Isnt it supposed to be stationary unless you move it? Maybe I need to make adjustments to the joystick.

Keep the help coming, I'd love to get this going.
 

Attachments

  • gorfss1.jpg
    gorfss1.jpg
    85.2 KB · Views: 9
  • gorfcpu1.jpg
    gorfcpu1.jpg
    100.7 KB · Views: 7
It lives! I swapped the CPU at J3 from Space Zap and got the screen below. So now I know this CPU is the culprit. I tried swapping Z80's just to rule that out, no difference.


Only problem is there is no sound either. Tried swapping amps with no difference. Sound works in Space Zap, so is it safe to assume another board is bad? Which board puts out sound?

Also, I'm noticing during play, my ship goes up on its own. Pulling down on the joystick will bring it back down, but letting go makes it go up again. Isnt it supposed to be stationary unless you move it? Maybe I need to make adjustments to the joystick.

Keep the help coming, I'd love to get this going.

Did you try swapping the two custom chips? They are the other two 40-pin chips....that arn't the Z80:). Each of these two customs are different, so don't put them in the wrong location. Sound is also handled by the board that the harness plugs into, as is controls. Joystick issue could be on this board also....or on it's opto board (located under the joystick).

Edward
 
I didnt go that far, but if they are "custom" I assume they cant be swapped or easily replaced? Either way it seems I should look for a complete boardset when you combine the sound issue as well. I can confirm all the smaller RAM boards are good, they all work in both games, as does the pattern board.
 
I didnt go that far, but if they are "custom" I assume they cant be swapped or easily replaced?

Only replacement is robbing them from another board. All Astrocade board sets have them (Gorf, Wizard Of Wor, The Adventures Of Robby Roto, Space Zap, and probably others.....Professor Pac-Man, Sea Wolf II, Extra Bases). Now, other things can go bad on the CPU board...since those customs are socketed, it's easy enough to swap them into a working game to rule them out.

There's also two customs on the input/output/audio board. These two customs are identical (but different from the other two customs on the CPU board). Swap these chips and see if you now get audio....and the controls work properly.

Edward
 
Back
Top Bottom