Gorf Restoration

[Scottacus]

I've never owned or refurbished an arcade game but I've always wanted to get a Gorf game for the basement.  My buddies and I fed way too many quarters into these in the early 80's and I figured that this game would still be fresh today because of its multiple games within a game.  I found one within a couple hundred miles of us for sale on Craigslist and was a little dismayed at what kind of shape it was in.  The entire machine was covered with grime inside and out, there were even dried leaves in the base of the cabinet.  Some repair man had cut out several of the light fixtures and there were exposed line voltage wires inside the cab.  The control panel was badly scratched up, the lens for the joystick was caved in, the plastic sponson on the back that protected the CRT neck was cracked in one corner, all of the locks and coin mechs were missing, one of the leg levelers was torn off and the side art was gouged. 

The good news was that the game would power on, drive the monitor and make some sounds.  When power was first applied, the coin counter went crazy and kept registering coin ups but that went away after the power was removed and restarted.  The ship would drift to the left and not move up or down but the fire button worked and the game seemed to play correctly.  The test screen showed that the move left and down controls were both stuck on but all of the other switches were functional.  I guess I really wanted a Gorf game because I ended up buying it and lugging it home in the back of our minivan.

I had found a GREAT refurbish article on this site by Spyridon that can be found here http://forum.arcadecontrols.com/index.php?topic=80733.0 so I had a good idea of what was on the inside of the Gorf game before I bought the game.  I won't go through all of the gory details of the refurbish here since Spyridon has already covered that but I will go through the bits of my refurbish that were different to help anyone else who might benefit from my experiences.  here is a link to the Gorf manuals and schematics http://www.arcade-museum.com/game_detail.php?game_id=7983 from KLOV.  These were invaluable in trouble shooting the machine.  More to follow...

[Generic Eric]

Sounds cool.  The more gorey the details the better.  Get the smell-o-net plugin for chrome to upload the funk from the mold.

And pics, lots of pics.  If you are worried about hosting them, upload them to this thread.  That way when yahoo goes under and no one buys flickr, we can still see your pics.

[Scottacus]

Sorry I can't upload the smells but I did have Vincent Price's line from Thriller going through my head as I cleaned out the cab as he said "the funk of 40,000 years...".

Here are some photos of the game in the condition that I found it.  Starting with the cabinet, over all it was in pretty fair shape.  There were some deep gouges in the sides and the artwork had been defaced but structurally everything was pretty good except for a little rot on the base corners of the cab.





The instructions had been worn off from the metal panel that sits under the joystick



Some of the lighting wires had been cut and taped off and others like the purple one here were just sitting there waiting to fry someone with line voltage.



I didn't know about this until I took the cab apart but of course I made the game safe first!

The inside was pretty well grunged up and had leaves and lots of fasteners that the repair guys lost or tossed.





The one that nearly gave me a stroke was this little screw sitting in the bottom of the metal enclosure for the boards!



I tried the game at the warehouse where I bought it and transported it home on its side.  If that screw had slid around and shorted out one of the boards to the metal chassis I would have been royally screwed!  I was very fortunate to not have more problems on my hands but between the hot wire and crap thrown into the cab.

[Scottacus]

I started by pulling out the transformer board and the metal enclosure for the game boards.



I then carefully washed everything up with soap and water.





There are scads of wiring harnesses and these were cleaned with a tooth brush while the rest of the cabinet was scrubbed and cleaned.



Once everything was clean and dry I restarted the game and it worked just like it had before.  I did this after every major act in the refurbishing just to be able to isolate any new problems.

[Scottacus]

I checked the voltages on the linear power supply and they were all pretty close to the specs for the machine but a couple of the big caps had leaked and one of the diodes had burn marks at both terminals so I ordered a new cap kit from Bob Roberts along with a cap kit for the Wells Gardner 4600 series monitor as well as locks, leg levelers and some other parts.

My primary concern was getting the joystick fixed so that the ship could move in all directions.  The Gorf joystick uses flags to interrupt a signal from an IR LED and photo transistor to determine if the joystick has been moved.  A voltage comparator determines if there has been a change in the voltage sent by the phototransistor and passes that information on to the game computer.  Ithat the checked out the voltages and quickly found that the LED for the "move left" optocoupler was not working.  This is what sent the signal to the board that was making the ship always drift to the left.  Unfortunately the original part is no longer available so I did some digging and found that someone had used a Fairchild H21A1 optocoupler with good results so I ordered one of these.  It was interesting to see that you could make the ship move to the right even though it drifted to the left.  I take this to mean that the game strobed the joystick to check for right move before left, that was pretty lucky for me!

I then took a look at the output from the voltage comparator and found that the set of pins that controlled the up motion never changed voltage while the LED and phototransistor both worked appropriately.  This is why the ship wouldn't move up because the signal from the optocoupler never got past the voltage comparator.  I was able to order a new LM339 so that was a pretty easy fix.  Here is a photo of the joystick board, the optocouplers have the slits in them (CR1-4) and the bad LM339 is U1.



Once the replacements came I removed the bad parts and soldered the new ones it.  It worked like a charm, now my ship moves in all directions and the game suddenly got a lot easier.  Watch out evil Gorfian Robots...

[jennifer]

     "Nice job cadet".... Giggle, Jennifer tried to do the robot computer voice , My Gorf, (a cocktail) had a dead rat in the bottom of it, well the bones anyway, apparently they turn to a stinky liquid goo at some point.

[Scottacus]

Dead rat?!  Let me check on that..

Yep that trumps dried up leaves on the grossness scale!

[Scottacus]

Next up was repairing the metal joystick panel.  Most right handed players rest their left hands over the instructions and most Gorf games that I've seen have these instructions damaged to one degree or another.



Spydron found a source for a replacement in his Gorf restoration but that option has since dried up.  I made another post on this site under artwork where I detail the process of using a product called Decal Pro to make replacement full color artwork using a color laser printer and the Decal Pro system.  http://forum.arcadecontrols.com/index.php/topic,143990.msg1495692.html#msg1495692

Here is what the repaired joystick panel looked like after I was done repairing it.

[Scottacus]

The lens for the joystick was dented pretty badly so I needed to repair that also.  Once again I could find no after market solution so I made one myself.  I wanted to put that technique in its own post so that folks could see that on the artwork section of this forum, the details are at http://forum.arcadecontrols.com/index.php/topic,144009.0.html

Here is the before



and after

[Scottacus]

I removed the coin door and repainted it with Rustoleum hammer finish black and cleaned up all of the internal components.  The 25 cent plastic pieces were pretty scratched up so I used rubbing compound followed by polishing compound and then Miracle X to restore them.  I also installed coin mechs so now the door will coin up with quarters.  New matching keyed locks were also added to all of the doors.



The T molding was removed and I used a heat gun to remove the old artwork.  The glue left behind came off if Goo gone which is a product that my daughter told me about.  I've used just about every solvent to remove old glue over the years and this stuff is amazing.  I went over the entire cab and filled all of the gouges and dings using a water based filler.



I then primed the entire cabinet prior to repainting it.  I took the back door into Hallman Lindsay and they color matched the blue in a acrylic enamel and I copied Spydron's grey for the bottom of the cabinet.  I tried thinning the primer down with water and spraying it with my old high pressure jamb gun that I use for spraying lacquer and the results were a white cab and an entire room covered in white overspray!  I tell you it took a day to clean that all up...

I then went out an bought a HVLP sprayer and that was THE WAY to go.  I experimented with dilutions and found that 1:1 to 1:1.25 water to paint worked the best with this gun.  The blue is a great match and after several coats the machine looked great.  I also masked off the internal window artwork and repainted the black on the inside of the cab around the screen with spray enamel.

Next I took a page out of Spydron's restoration and used a old tooth brush to make the white star splatter pattern on the cabinet using the left over primer.  It worked absolutely perfectly and the cab now looks like it just rolled off the production line.



The plastic cover for the monitor yolk was fractured in one corner so I fiberglassed this from the inside and repainted the cover black.  It turned out really nice.



I made aluminum covers for the bottom corners of the cab to hide the areas where the cab was just too rotten to repair with filler and also added an aluminum base to the back bottom of the cab.  The old leg levelers were removed and new ones from Bob Roberts were installed through the bottom of the cab.  New black leather T molding was installed and new artwork was applied to the sides.

[Vigo]

  Wow! Very good!

[Generic Eric]

I haven't seen this cabinet in person.  What is going on in the red circle? 

[Scottacus]

It is a plexiglass piece that is back lit and made to look like the canopy of an x-wing or other space fighter.  The light in the top of the cab illuminates it.

[Generic Eric]

It is a plexiglass piece that is back lit and made to look like the canopy of an x-wing or other space fighter.  The light in the top of the cab illuminates it.

Thats cool.  Any chance you have more pictures that focus on it? 

[Scottacus]

Sure, here you go.





Two brackets on the sides and one on top hold it in place.  It has a bit of a star field pattern painted onto it.

[Generic Eric]

Cool, Thanks.

Your project turned out great.  Do you find the flight stick makes it spacier?

[Scottacus]

My buddies and I loved this game in the 80's and I still love it today.  The multiple games within a game, a big "boss" to beat at the end of each level, the rankings, the taunting by the SC-01 voice chip, the intensity and aggressiveness of the Galaxians, the very difficult at higher levels of space warp...

The joystick is the same one used in Tron, the only difference its that this one is solid black.  It feels great and the grommet has just the right resistance to it.  I only have this one game and this is the one I have wanted for years.  As a bonus, it has been a fun project to refurbish.

[Scottacus]

The new set of boards came for the Gorf machine and I was able to replace the bad 0066-117xx with a new chip and now Gorf plays in glorious stereo.  All of the left channel sounds like stomping space invaders, twirling galaxians and the firing of the laser cannons are now there!  The game sounds great now and of the set of boards that I received from the E-bay auction the CPU, Game board, ROM and one RAM board all work fine the pattern board is dead and one RAM board puts yellow or blue patterns over the game depending on which of the two slots you put it in.

[tomstewdevine]

Really great job with this. Very impressive.

[Generic Eric]

The new set of boards came for the Gorf machine and I was able to replace the bad 0066-117xx with a new chip and now Gorf plays in glorious stereo.  All of the left channel sounds like stomping space invaders, twirling galaxians and the firing of the laser cannons are now there!  The game sounds great now and of the set of boards that I received from the E-bay auction the CPU, Game board, ROM and one RAM board all work fine the pattern board is dead and one RAM board puts yellow or blue patterns over the game depending on which of the two slots you put it in.

I don't have a manual to interpret everything, but I acknowledge that you have bad boards that prevented you from playing.  Are these easy fixes?  Are you going to repair them?  Also, did you receive an additional card basket? 

[jennifer]

     Im a bit concerned over those marquee lamps, That's sposed to be a fluorescent not? ... It seems somebody chopped those fixtures in. Those bulbs will create A lot more heat then necessary.

[Scottacus]

Thanks for the kind words Tom,

I don't have a manual to interpret everything, but I acknowledge that you have bad boards that prevented you from playing.  Are these easy fixes?  Are you going to repair them?  Also, did you receive an additional card basket?

 

As far as fixes are concerned, the 0066-117xx chips are socketed so they are easy to replace, the problem is finding them.  They were in Bally Astrocades, a few arcade machines

Extra Bases
Gorf
Robby Roto
Seawolf II
Space Zap
Wizard of Wor
 
and some pinball games.  Otherwise they were a propriatory Bally chip and no one has reverse engineered them as far as I can see. 

If I get some time I might trouble shoot a few of the bad boards but for now I am having too much fun playing the game.  I do have a spare card holder that looks to be in good shape.

As far as the lights are concerned they are supposed to be 25W incandescent bulbs, some frosted and some clear (per the manual).  I found some inexpensive 25W standard base LED bulbs from Menards and put those into the game.  I share your concern about heat and these run at room temp and look great (some are frosted and some clear).

[yotsuya]

I love Gorf. You've done a great job here.

[Scottacus]

Thanks yotsuya.

And now for the first time since 1982 or so I made it to Space Avenger!!!!  Maybe not a high score for some (39,970) but for me, it made my week and its only Sunday

[cw]

great job... this is what people aim for when doing a restoration

[Spyridon]

Nice work on the control panel.  Not sure you need it, but This Old Game is planning on another run of the control panels.

[Scottacus]

Welcome to another episode of "This Old Gorf Machine", the show where I get to spend half a day trouble shooting some new problem with the machine.  Today's adventure is figuring why the machine keeps firing even when the trigger isn't pressed. 

Does every old machine give you folks problems like this?!?

This new problem started late yesterday so my first thought was "what was the last thing that I did to the machine that might have screwed this up?"  The RAM test was a possibility (even though it worked well after the test) so I rechecked the RAM, nope all is good.  Maybe the trigger leaf switch is intermittently bad so I changed out the 33 year old switch, nope still fires without pressing the trigger.  Maybe a board went bad, I switched out all of them and no luck.  Maybe there is a short in the wiring between the leaf switch and the card box, nope all is good on the continuity tester.  Maybe there is a ground loop from the ground wire on the CP, nope not that either.

Now I'm running out of options so I watched the game play and in Gorf you can cancel out a previous shot by shooting again before the bullet leaves the screen.  Oddly the unwanted shots don't go rapid fire but wait till the previous shot leaves the screen.  Gorf also has a set of grain of wheat lights in the top of the joystick, near the leaf switch.  These lights go on when you hit an enemy ship, but not when you fire and miss. The wires for the leaf switch and lights run down the inside of the joystick inside a long tight steel spring.  The spring is there to protect the wires from getting crimped when they enter and exit the steel shaft inside the joystick.  Oddly the lights were on even when the bullets were missing the targets and the lights were off when the game wasn't "auto shooting" bullets.  Also the problem was intermittent, which made it even more painful since you can't count on the problem always happening (makes troubleshooting even more difficult).

Hmm, even though the continuity tester showed lack of continuity between the light wires and the switch wires I figured I should check the resistance.  Maybe there is a high enough resistance there to fool the continuity tester into thinking the circuits are isolated.  BINGO, there was a few K of Ohms resistance between the fire switch and lights.  I pulled the joystick completely apart, and a small nicks had formed in the wires from years of having the joystick moved around.  These must have touched the steel spring intermittently and sent DC from the lights down the leaf switch wire, causing the misfires.  I made a new harness and rewired the stick and now the game plays just like it should!!

That only took a few hours 

[Scottacus]

Just a quick update on reliability.  The game has been used daily for the last 4 months with zero problems.  I guess once you have ironed out all of the bugs on these old machines, they pretty much run dependably like the "tanks" that they are.

[Scottacus]

Over four years from the restoration of this game and it still runs perfectly!  Once you get them fixed, they are good to go.

[Mike A]

Very nice. I have a Gorf cab that needs a bunch of work. I need a board set, but they are expensive.

[Scottacus]

The board sets do come up on E-bay pretty frequently but they can be spendy.  I usually don't check this forum much anymore but someone sent me an inquiry about the LM339 quad comparator chip.  I figured that I'd post to let folks know that the machine that I fixed up has given me many hours of service with absolutely no issues over the last four years just in case anyone is on the fence about fixing one up.  The initial work in getting an abused machine back up and running pays off in the long haul!

[behrmr]

The board sets do come up on E-bay pretty frequently but they can be spendy.  I usually don't check this forum much anymore but someone sent me an inquiry about the LM339 quad comparator chip.  I figured that I'd post to let folks know that the machine that I fixed up has given me many hours of service with absolutely no issues over the last four years just in case anyone is on the fence about fixing one up.  The initial work in getting an abused machine back up and running pays off in the long haul!

I’ve worked on enough Gorfs to know that just talking about how good they run seems to be the kiss of death LOL

Good work and good luck with keeping it running. It’s a great game.

If you haven’t a couple of things I would suggest

Make sure you have heat sinks on your customs on the CPU board. They get hot and burn up.

Put your CPU board on the outside of the stack for maximum cooling.

Some folks even put a fan in and point it at the stack

Carry on Space Avenger!

[Scottacus]

Thanks those are both great ideas! 

I had one bad 0066-117xx chip with the original board set and had to buy a new board to get that very hard to find chip.  I think that I'll take a look at those chips and see if I put heat sinks on them, I think I did but I need to recheck that after seeing your post.  The fan is also something I should look into since these boards are spendy and coming up on 40 years old.

I have a high score daughter board for the rack so there is no ROM board which opens up air flow in the stack.

http://forum.arcadecontrols.com/index.php/topic,149186.msg1555858.html#msg1555858

[Scottacus]

I took behrmr's advice to heart and made a 3d printable fan housing that has two slots that let it sit on top of the Bally card rack.



I then took two old 12v computer case fans and epoxied them to the top of the case and wired the fans together.  Here is a photo of the fans on my spare bally card rack, the square cutout allows part of the wiring harness to pass through while the fans blow air down onto the CPU and game board with its precious Bally 0066-117xx chips.



I'll tie the leads into a ground and 12v pins on the card rack once the epoxy is fully dry.

[Scottacus]

Here it is in the machine



And on the first test run a Space Avenger rating!

[Mike A]

That looks like a good idea, but shouldn't you draw air up and away from the components? You are fighting physics by blowing the air downward.

[Scottacus]

I'm not sure it will make much of a difference so long as air is moving past the chips.  The high score daughter board let me pull the ROM board out so the CPU board is in the outer edge of the case and the Game board has open space next to it.  By blowing air down with the fans directly over the 0066-117xx chips I get the most air flow possible over those super hard to find and prone to failure chips.  If I suck the air past them then the air flow is not focused on them.

I wonder if they were prone to failure because only one board can be on the outer edge where the case has a large opening and the odds that that board is the game board is 1 in 4.  If the Game board was on the inside then the air flow past it would be very poor and would let the chips heat up more.

[Mike A]

Yeah. It probably wouldn't make much of a difference.

[Nephasth]

The high score kit ---smurfs--- the game up.

[Scottacus]

The only difference I've seen is after a few waves the galaxians still set before dropping.  You notice anything else?