John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

Any one know of a good place to get a rebuild kit for an original Space Invaders power supply. Need to rebuild mine and I can't find a rebuild kit. Maybe someone that can put a kit together for me?

Try Ian Kellogg he is on here constantly..very good tech and parts supplier . Give him a shout in the shoutbox

I did but haven't gotten a reply back from him and I didn't want to bug him to death.

I remember John mentioning in one if his vids that someone else put together a kit for the computer space. Wasn't sure who might reply to this...

Tothwolf , went back and looked ...lol ;D

O.k. got a kit from Bob Roberts, however the two big filter caps are the wrong uf value. I sent a note to Mr. Roberts and he replied that they are modern equivalents and are o.k. to use. I always thought that you can increase the volt value but the uf had to stay the same. Thoughts??? Ian I'd love to hear what you have to say.

Old caps
20000 uf, 16 v
6000 uf, 35 v

New caps from Bob
22000 uf, 35 v
68000 uf, 35 v

I'm guessing that the higher uf may do nothing more than act like a better filter but I'm really not sure.

it will act like a better filter and slightly increase inrush current but that isn't a very high difference.

Thanks Ian.

I've been sending e-mails back and forth with Bob and he sort of said the same thing. Thanks for you input as it makes me comfortable enough to install them now. I don't minds mods as long as I know they will work.

O.k. installed all new caps in the power supply and still have the same problem. With the -5 pot turned all the way I can only get to -5.2 and with the +5 pot turned all the way I can only get to 4.9 volts, with the mother board plugged into the harness. If I unplug the harness from the mother board then I can set -5 and +5 perfectly.

Here's what I have done...

The game had stopped working, it had lines under the alien ships that you couldn't shoot through. I had this problem before and resetting the voltages is what fixed it so when it happened this time the first thing I did was to check voltages. They were not set right so I tried to reset them but could not get to -5 or +5 so I ordered a rebuild kit from Bob Roberts. I can with caps only. I installed the caps. While I was at it I also pulled the mother board and installed a cap kit on it too. I separated the daughter board from the mother board and cleaned the connections, I removed all socketed chips cleaned the legs and re installed/reseated the chips, I went over both boards and touched up any solder that I thought looked crummy and reflowed all header pins and made a small repair to the board edge (the harness connector looks fine). Then I reinstalled the daughter board on the mother board. I then put the power supply back in the game and set the voltages with the harness not connected to the mother board, then plugged in the harness to the mother board and rechecked the voltages. They were way off, the -5 was around -5.45 and the +5 was around 4.65. I tried to reset them but got the results listed above, however the game works now even with the voltages sort of wrong. I feel that over time this can only cause problems with the mother board so I would like to get the power supply sorted so that I can actually supply the correct -5 and +5 to the mother board. I have no problems setting the +12 volts, I can get it set to 12 volts on the nose.

Idea's???
Any ideas what I should look at next, I'm sure it's something with the power supply and not the mother board and harness.

I hope this link works.
https://www.facebook.com/thomas.f.pfeiffer/videos/10206045396310997/?l=7952607930697282068

So today I had a little time to fool with this thing. I found in the schematic that there are four diodes that sort of tie the -5 and +5 circuits together. I removed them and tested them. All were good however I found one of them was loose, it had one leg that I could remove without desoldering it. I resoldered all four diodes back into the board and made sure they were in there real good. Still got the same problem. With the pots cranked all the way I just can't get -5 or +5 volts. I guess next up is to check the transistors that are mounted in the heat sink? Maybe the resistors that are inline with these two circuits? I don't know what's left?

Alright haven't fooled with this thing since the last time I posted about it. Weeks have gone by but I've been thinking, it just might be something on the mother board and not a power supply problem. Thoughts???

I have been pretty slow to respond here lately but reading through this. 4.9V is more than good enough. I would move on from there. What issue are you having?

I can only get 4.9 volts if I crank the pot all the way. Same with the -5, I can get to about -5.1 if I crank the pot all the way. This is with the board plugged in. If I unplug the board I can get 5 volts and -5 volts with the pots centered. Something has got to be pulling the power supply down. I'm guessing that if I just ran it the way it is it would work for awhile but sooner or later something is going to let the smoke out. Maybe I'm wrong and being too picky but I just want to make sure it's right before I push it against the wall where it's hard to get into the back to work on it.

that sounds fine to me.

So give it a go with the pots cranks all the way huh?

there is probably something going on making it need to be cranked all the way but 4.9V is more than fine and I would move on to something else. I still haven't see anything about what the game is actually doing to help you out.

Well the game quit working, and I couldn't get the voltages to work so I installed a cap kit in the power supply. Still couldn't get the voltages right and game still didn't work. So I installed a cap kit in the mother board, touched up dozens of cold solder joints and then... I did something non of us should EVER do. I used solder to touch up the board edge where the wire harness connects to it. I know I shouldn't have done it, and normally I wouldn't BUT I noticed that someone in the past had already done it so I figured the harm had already been done and I can always install a edge replacement and new harness connector sometime in the future as I did in my Ms Pacman. And wa-la! The game came alive, BUT the voltages are still not right. I figure that something somewhere has high resistance and so the amps are probably high (no I didn't measure the amps, I don't know what the amp spec is so until I find that info why bother?) and high amps usually lets the smoke out at some point. So that's what I'm trying to avoid. At this point the game turns on a works as it should, just with funky voltages. Heck I've set the pots right in the center with the voltages at 4.6 and -5.4 and it still works. So chase down the problem or live with it? I don't know, let it run for awhile and see if I can find something hot to the touch on the mother/daughter board set? I'm really not sure how to go about this at the moment. If I just let it cook itself that would be one way to find the problem. Probably not the best way but I'd find it.  :P

Just leave the power supply alone. You are chasing nothing at this point. As long as its near 5V you are fine.

O.k. I'll try setting it at like 4.85 volt so that I don't have the pot pegged and I'll move on. Maybe I'll rebuild the control panel.

Nothing wrong with the pot pegged, get as close to 5V and leave it.

O.k. Thanks Ian.

I haven't had time to work on this in a while. A buddy stopped by this last weekend and I plugged it in to let him play a game. The bom BOM bom BOM sound of the alien ships marching across the screen was gone. It's never given me trouble before. Also since I haven't worked on this in a while the above stated voltage problem has not been fixed. So I'm wondering. If I was having a problem with not being able to achieve +5 or -5 volts with the PCB plugged in, to me it seams that something on the PCB is loading down the power supply. Now all of a sudden one of the sounds is missing.... Is it possible that whatever was loading the power supply finally died? Keep in mind I haven't had time to plug it in and check if my voltages are still messed up or not. But let's just assume that's what happened, my guess is a chip for that sound is bad, so which one is it? Yes I know I really need to check my voltages before asking that question.

O.k. been since last spring. Weather is getting cold so back to indoor project. Time to get this Space Invaders done so I can move on to another game.....

Bob Roberts is still closed, I need to replace the PCB board edge and repair the pins in the connector or replace the connector any idea's where I can get this stuff. (Ian I'll buy them from you if you carry this stuff.)

By the way I'm doing this because I'm still having a voltage issue. Still can't get 5 volts or -5 volts with the PCB plugged in. I noticed that the edge of the board is in bad shape. I don't know for sure that this is the problem but if the board edge is in bad shape and I can fix it then it's one more thing that I can rule out, and it needs to get done anyhow. Same for the connector, someone in the past soldered the board edge so I'm pretty sure the pins are spread, I may be able to gently bend them back up if I can replace the pins/connector then I'll do it.

So, I haven't had time (as usual) to work on this, BUT... I did contact the guy that I bough the Space Invaders from and he had a spare PCB and spare power supply, both of which he had sent out and repaired. He said he hasn't tested them yet, however he loaned them to me so I can try them in my game. This should hopefully let figure out if "MY" PCB is pulling down the power supply, or if "MY" power supply has an undiagnosed problem even after I recapped it. First thing I'm going to try is to use "HIS" PCB with my power supply. Then "HIS" power supply with "MY" PCB. I'll let you guys know what happens, when I get to it.

O.k. So I tried my friends power supply and it was bad, wouldn't make any volts at all. So I put my power supply back in and tried it with my PCB and got the same results that I've been getting. +4.7 volts and -5.2 volts. Can't make 5 or -5. So then I put in my friends PCB and got the exact same result. So this points to a power supply issue and not a PCB issue.

Also I noticed today that when I was using my PCB the background sound (bum Bum BUM Bum, bum, Bum, BUM, Bum) is gone and when the mother ship flies by the sound is very weak and tiny. All other sounds working fine. This bugs me. It WAS working. I'm sure my power supply issues didn't do it any good.

So anyhow one of the caps that I got from B. R. was a different capacitance and I questioned that but was told that the power supply would work fine. Now I'm questioning it. It was one of the two big filter caps. I know that B. R. was trying to sell me a cap that saved me some money but I'm wondering if I should just spend the money and buy the expensive caps and give it a try. Only other things that I can do is remove one component at a time and test them, or just get a switching power supply and adapt the game to use it. Personally I like having the original stuff, but I guess it is inside the game where you can't see it.

So what do you guys think???

Edit: just thinking about this. The reason I replaced the capacitors to begin with was this voltage problem so I doubt it's the new capacitors. Hmmmm.

I am suspecting that the 2n3055 transistor on the large heat sink might be bad. Looking at the print it is the only part that is part of both the -5 volt and +5 volt circuits. On Mouser I found a 863-2n3055g. Anyone know if it is compatible? Ian????

Wow I can't believe I haven't worked on this thing in that long. Any rate I finally found time to putts with it..............

MONTHS ago I bought the transistors that I listed above, along with some others and decided to check them, however before I put them in I had watched a youtube video where someone having the same issue as me found the big ceramic resistor (.18 ohm 5 watt) was bad he changed it and his problem was fixed. I looked at the print and saw that it "could" be an issue so I pulled it out of circuit and low and behold it was WAAAAY out of spec. So I ordered a new one and changed it. DID NOT FIX ANYTHING. So this morning I changed all the transistors that I had purchased for it. Did not have time to turn it on and see what it does and I didn't have time to use my meter to test the transistors either so I'm not sure that it's fixed. If it's not, after looking at the print there are a bunch of resistors that are sort of in the middle of the +5 and -5 volt circuits and could effect them both so I'll start pulling them out of circuit and testing them, along with some of the diodes (there are too really big diodes that the board under them looks burned, Hmmmmm?). There isn't a lot more to look at here. I'm even starting to wonder if the transformer is making enough voltage for the power supply to work so I'm probably going to check that too. I honestly can't believe that I don't have it fixed yet.

Decided to give up on the original power supply. I bought a brand new switching power supply with the 8080 adapter from The Arcade Shop. Just installed it set 5 volts with the processor disconnected, turned the game off, plugged in the processor and turned the game on. The new power supply turns on for a few seconds and then goes into shut down. I shut the game off confirmed my connections and turned it on again. Same problem power supply comes on for a few seconds and then goes into shutdown. Something on the processor board has got to have a short.

Any ideas would be appreciated.......

So I needed to change the wire harness connector for the pcb because I knew it was not in the greatest shape. Was really hoping that it would solve the problem. Nope. Brand new power supply goes into shut down  with the pcb hooked up. I’m at a total loss. I would really appreciate if some of you gurus would reply. I’m going to call arcade shop sometime this week but I’m really lost on this problem and could use some friendly advice.

Talked with Arcade Shop today. I felt that this thing must have a short on the PCB. There is one sound missing (thump thump sound) and the flying saucer sound is really weak. The guy I talked to at Arcade Shop felt that one or both of those chip is most likely shorted to ground and at the very least I should investigate that. I was sort of getting that feeling too, but really wasn't sure until I talked to this guy. So hopefully sometime soon, I'm going to pull those two chips and see how the board runs without them. It won't have those sounds but it should (hopefully) at least run. I'll let you know what happens after I get a chance to work on it.

So I pulled the two chips for the UFO and the thump thump sounds, plugged the board into the harness and turned the game on. The new power supply just goes into shut down almost instantly. So either the new power supply is bad or my game board has a dead short. I'm not sure what to do now..... Any ideas????

Wow talking about digging up old threads....

So here's an update.

If you look at what I had said earlier in this thread I had purchased a switching power supply with adaptor for Space Invaders from Arcade Shop. It didn't work, it just went into shut down which indicated a short on the game board. I called Arcade Shop and they told me that it was a short on the game board and not the power supply. So whenever I had time I searched and searched for a short on the board. To be honest I knew it was beyond my ability to find the short but I tried it and....... I didn't find it.

I hired the job out to a local shop that's right around the corner from me, called Big Toys. They sent their tech out, he looked at what I had done and did a little diagnostic work at my house and found that they new power supply was totally screwed up. When I checked the voltages they weren't bad but he used a simple light bulb to load the power supply and the 12 volts jumped up above 12 volts. After a brief conversation him and I both agreed that he should take the new power supply (from Arcade Shop) and the original power supply along with the game board back to his shop where he has all his diagnostic equipment. Today I got a call from him to give me an update on the progress. Not only was the new power supply screwed up it was outputting more than 30 volts on the 12 volt supply when he used his equipment to put load on it the right way. He was hoping that it didn't hurt anything because it went into shutdown so quickly (when I turned it on, installed in my game). Well first he found the short, bad capacitor on the 5 volt side of the board (nothing to do with the 12 volts being too high), AND he then checked the 12 volt side of the board. Well there is a clock chip that it fried and he's looking for one. I don't know the number of the chip but he said he was going to look over some old Midway boards to find one. Sounds like it might be a chip that's no longer made. I might call him back and ask for the number so I can look for one too. So that's where it's at. Sucks but at least it will live again. I'll leave another update when I get one.

Yay! It's alive! Got my game board back today and the tech that I hired also brought a new switching power supply with him. We installed the game board and new power supply and BINGO, it's working again.

So what had happened is that the power supply that I got from Arcade Shop was faulty, it was putting out over 30 volts on the 12 volt line. BZZZT! The timer chip that I had mentioned before and one capacitor basically acted like a fuse and stopped anything else from being damaged. Still....

Also before I got this repair tech involved, I had replace the chips on the board that control the "thump, thump" sound and the "ufo" sound. I was never able to test them due to the power supply issues. When we turned it on today all of it worked. So even the repairs that I had made were working.

At any rate I'm not saying anything bad about Arcade Shop. I'm sure when all this first happened, if I had figured out that the power supply was bad they would have stood behind their product, I just didn't know any better and I'm pretty sure that by now I'm well beyond any warranty period so I'm just going to chalk this up to experience.

Next up rebuild the control panel and maybe a Braze kit.

Still looking for LED's that look like normal light bulbs for it...

Well.....


It didn't last long. I installed the Braze kit and it didn't work. Called "highscoresave.com" and talked to the gentleman that runs the place. He thought that I had a bad kit and so he swapped it with me. So I installed the new kit. It worked great, except that after less than 5 minutes the video signal fads away and I get a blank screen, game plays blind. So just to make sure I removed the Braze kit and it does the same thing. I turned up the brightness on the screen and I can wash out the screen so I don't think it's the monitor. I call the guy that fixes my boards and he had me drop the game board off with him to look at. At the moment he has the board and I'm waiting to hear from him. Damn so close....

Sometimes when I receive those power supply they have a switch and they are set 220 volts.

Ive had 2 that way... only one ever installed but it didn't harm anything. Always check those and set your switcher voltages before you plug in your board


Sent from my iPhone using Tapatalk

Got the board back, they played it for 14 hours without a glitch. So I guess I need to look into the monitor and the wires that transfer the video signal.

Thanks Hgloth. I already pitched the other power supply but I'll make sure to look for that in the future.

So I fixed the video issue. I found the anode wire was not fully inserted into the fly back. The video looks great now. It’s missing the invader hit sound. That gets fixed next and then I’m going to try to find some LEDs that spread the light like an incandescent bulb and then I’m calling this thing done.

And the video issue is back. I think it's just time for a full monitor rebuild and replace the pins for the video signal where they plug into the monitor.

On the plus side I did find time to fiddle with this game a little and I fixed all but one of the non working sounds. The last one is a little beyond my skill set so i'm going to hire it out.