Hey everyone,

Just getting started with the pinball hobby and picked up a non-working Mars God of War last week. I studied electronics for a few years in college and figured this would be an interesting little project.

From what I've been reading the first thing to look for on these machines is intact backglass which mine has. The biggest issues I've seen so far are fried high voltage transistors on the driver board that have gotten so hot that the PCB started to burn and melt. Looks like it isn't the first time it happened to the board as someone soldered jumpers to the transistors to replace the burned off PCB traces. Also noticed a Texas Instruments IC has blown its top off although I'm not sure if that is physical damage or from an electrical issue. The main other issues I've seen are the front 4 drop targets are all broken off, someone has put a screw though the playfield from underneath (although it's back behind the pop bumpers and not very visible once I remove the screw). The rubbers are shot and there was a melted coil sitting in the bottom of the machine (there are still a number of coils under there that look original, I'm wondering if those are the culprits that toasted the boards). Also noticed the wall plug has been hacked off for some reason so I may have to do some investigation around the transformers too. Anyone know how well those transformers and other power supply parts hold up to the test of time?

Anyways if anyone could give some good starting points on restoring the machine I would love to hear them!

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Ok, so I've done a little bit of reading so far and the two biggest debates I'm having at the moment are what replacement boards to go with and what to do with the playfield.

At first I was thinking of going with the Swemmer mpu and driver boards but I've been reading that they are more of a direct copy of the originals just with LED's in there to look fancy. Some of the other boards supposedly have solenoid testers built in and other features which could be nice. Sounds to me like the Pascal board is the way to go since you can eliminate a few connectors as well but part of me is saying to myself yeah but if something goes bad on an all-in-one board you have a pretty expensive piece of scrap PCB.

And for the playfield I'm wondering if the mylar should go or not. You can see in the flipper picture that one of them has actually put a groove in the stuff and then it peeled up above the pop bumpers when someone put a screw through the playfield as well as some edge peeling at the top left.

Any thoughts?

Thanks

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So I got a bunch of replacement parts in. Switched over most of the stuff I bought except the old orange capacitor on the transformer board. Can't remember my electronics theory all that well anymore but my gut is telling me that orange filter cap is polarity specific despite it having no markings. Green wire is typically negative on these gottlieb machines though correct?

Gave the machine a quick plug in to see if I even had the base lights come up. Managed to trip the 20amp circuit breaker and no sign of life from the pin before that. If I were to guess, I'd say the problem is somewhere on the transformer board but then again I'm really rusty with this type of thing. Any tips on isolating problems like this? Maybe tired transformers?
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Well I made some small progress today. Can plug the thing in without tripping the 20 amp circuit breaker the machine was plugged into.
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Keeping all the board fuses out for now but at the very least I can see some of the lights on without blowing breakers. I found some power supply rebuild kits for Gottliebs on big daddy, but their site seems semi defunct so not sure if I should try and source the parts elsewhere or not.

Guess tomorrows job will be to start checking voltages down on the playfield power supply then work my way towards the one in the back box

Thanks for that info, managed to google it to get the scoop once I knew what I was looking for. Floods are rough, especially when you store stuff for your business downstairs...

So I started checking some voltages around the machine to get a bit more of an idea what's going on. Also, wondering if this is the original power supply board? I thought I remembered reading something about adding LED's to the power supply to see if it's working but this one already has them.

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Not sure how well this will show up on the computer screen but how do these voltages look to you more experienced people?

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I think the ones that seem the most off to me right now are where I'm reading 30.2v across the DC terminals on the solenoid rectifier bridge which is supposed to be 24v. When I install the fuse F6 for the solenoids I lose most of the lights on the backbox but not sure what that really means yet.

the 4.3v to 4.4v reading across the 5v rail on the backboard power supply seems a little low too. Didn't realize it until now but there does seem to be some heat burns on the power supply board under one of the diodes.

Any thoughts on the voltages?

So I got lazy and went with a Pascal board rather than mess around with boards I may never be able to fix. I've forgotten too much from my college days to be bothered to get knee deep in board repair. I've certainly gotten some better results from this board compared to the originals...

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Also, I had someone send a PM asking what the original back glass mounts looked like. Here's a few pics of those:

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So I've definitely got a lot more work to do on this machine but at the very least the thing is alive to some extent. There is no sound to speak of yet and right now the game just seems to be flipping one solenoid over and over. Any tips on where to go from this stage?

I'm not sure. I have a feeling the voltages were off that little bit just from old components.

And yeah, I remember mention of getting rid of those inner backglass mounts. I'm leaving it off the machine altogether until I get it running better and find a better design. I remember being told to use a Black Hole style mounting but the only picture I was able to find of the door open was this:

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do you basically just wedge the glass into the door frame and screw in some flat steel to clamp it in place? probably throw some rubber between to protect it?

So I got the machine running today! All the switches/sensors in the ball release were buggered up, but I think I have them fine now. The main issues I'm seeing right now are the lower right LCD screen isn't working correctly (You can kind of see it in the last picture I have of the back glass. All the centre portions are lighting up too. Any tips on this?) Also I have no sound yet whatsoever. The variable resistor for its volume doesn't feel very good, so maybe that will be the culprit. From there I'm not quite sure where to look. Also have an issue with the lower drop target bank solenoid. I played one game fine and now it seems to be sticking on something.

I guess now it's just a matter of slowly ironing out the gremlins in the machine. Still good to see the flippers shooting a ball either way!

Been a little swamped with xmas and new years, but I will definitely give that a shot when I get some more time to tinker with the machine. I managed to get the fourth pop bumper working properly at the very least.

I've got a question for you guys that have one of these machines up and running. What are the triggers on the logic side of the machine to raise and lower the stargate ramp? Mine just sits lowered no matter what and I'm trying to isolate the issue. The other one I'm wondering is how do I get the multiball to activate properly? I can hit all the drop targets and the warbase light starts flasing and then I lock a ball in each of them. Once I've done this though, if I shoot the ball up the lauch warbase lane, the ball will go past the rollover in there and then just get stuck on the right side locked ball. If I hold my finger on top of that right side rollover for ~10 seconds though, the display pops up with hyperforce and will unlock for the multiballs. Is there a switch or something else in the sequence of operation that I'm missing?

Nice setup you have there Steve. Also... I'm angry at you! I found the System 80 thread and read the most recent set of posts. No all I'll be looking at are my drop targets that aren't quite the right colour! Mine seem to be a far closer match colour wise than yours though, hardly noticeable even side by side.

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So it looks like my problem with turning on the multiball is that I'm probably missing a part... I watched the TNT video where they do a little bit of gameplay including getting the multiball.

Here's a link if anyone is interested:

If you watch around the 11:00 mark when he gets the multiball activated, the game shoots the ball back up the top whereas mine it will just keep rolling until it gets stuck on the ball lock below. Took a look underneath and I realized what the two marettes likely led to at one point. Anyone able to get a picture of what else is supposed to go along with the rollover here? My Dad works at a steel fabricating place, I have a feeling I'll be making up some CAD drawings for him to laser cut some sort of ball launcher assembly. Can't imagine I will have an easy time finding a proper replacement one...