So I read through Clay’s Guide to repairing vintage Bally SS machines and as usual, it is extremely thorough and well laid out. Of particular interest to me was the ROM and jumper issue with the MPUs. Definitely saved myself some upcoming headaches and frustration. Going to start with the Power supply and do all of the recommended upgrades, get it right and then tackle the MPU. So glad I came across a really good looking replacement because mine has way more alkali damage then I care to deal with. I don’t want to use this POS at the heart of a refurbished machine...at least the ROMS look perfect.

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I have refurbished several of the Bally/stern power boards... from now on, I’m replacing them with new boards for what it’s worth.

The mpu can always be saved, but finding a better one may be preferable

The power supply looks surprisingly good Chosen. The pins are clean and all fuses look intact. The -49 seems to be one of the stronger of the series. Just going to replace the pins caps transistors and rectifiers.

The MPU actually looks salvageable, but I got a completely clean one for $60 with a lamp board thrown in...couldn’t pass that up.

The good news is that these are really easy boards to work on. I am very excited about it.

Also reached out to a wood cutter today and should be able to get my cabinet panels cut for cheaper than me doing it myself and buying all those specialized router bits.

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Yea that -49 rectifier board looks to be in pretty good shape. All you'd really need to replace would be header pins, fuse clips and the bridge rectifiers. I would also replace CR1 - CR4 with matching diodes, as yours appear to be mismatched. You *can* replace the varo 712E devices with a bridge rectifier if you'd like as well. I left them on mine as they worked just fine and the load was a bit lower since LEDs will be used for everything but the chase lights, so less heat and stress on those.
As for that MPU, I would call that dead. The amount of work to get it de-populated, cleaned, check all the traces for breaks, rebuild and test just isn't worth it in my book. At least you can salvage some of the chips and Roms from that board. But you have a 2nd MPU coming that is in much better shape, so it all works out.

“New” MPU arrived today. Looks awesome with zero battery damage. Just need to replace the sockets, swap ROMS, replace header pins and most importantly rework the jumpers for the SI 9316 ROMs.

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Looks good, one of the better -35s i've seen in a while.

What are your thoughts on this?

As I continue to disassemble and clean my SI. I am finding that the cabinet plywood with the art is better than I thought it was. There is one side that has a little delamination but I am confident I can epoxy it back and preserve the art. The MDF back of the backbox will need to be replaced but the side art looks pretty good. The front panel on the lower section of the cabinet is the worst and has some rot but it’s the only section with artwork that requires replacement.

My idea...make the head and cabinet structurally sound, mask off the side art and then spray the parts that have no art black to match. Then spray everything with a matte or low gloss finish. You will see imperfections and some chips so it may look a little antiqued but I think that may be pleasing and preserve at least some originality. I have watched a few videos with stenciling the art and it looks difficult and the results are less than perfect in many cases. The real challenge would be the coin door panel because that needs replacement of the art.

I don’t expect this to ever be a collector condition machine. I want it to look decent, be structurally sound and play well. The PF will go to a Pro for some touch up as it is will clean up really nicely.

Thoughts?

If you have the skills to accomplish all of that and you feel that the final product is what you are wanting, then go for it. Its very much up to personal preference and based on what skills you have.
My SI restore started with a game in horrid shape. Plywood de-lamination, rust, corrosion, outright broken parts, mouse nests and mangled wiring, so it was pretty bad. I was able to save *most* of the head, but the rest of the cabinet was completely replaced. I used Pinball Pimp stencils and had no issues. I wanted to learn the process and attempt to pick up some new skills as part of my restore. Here are some photos for reference. I plan to make a thread of my own once I get a new CPR pf and can finally get this project finished.

Before:
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During:
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And After:
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JDissen87 Wow...yours was really hammered! Beautiful work! It looks amazing. Couple questions if you don’t mind...

1) Did you have a tough time getting the stencils off after painting? I like to use very light coats when I spray. But I am not sure that’s possible with stencils. I have only sprayed arcade cabinets solid color. Good results with 2 coats. Maybe you used a sprayer and not a can?
2) Wood work. I have a good saw(s) and router and I am comfortable with doing that, but how did you get an exact template? Trace? CAD drawing?

Looks awesome

Yea, mine was routed for then left in a garage until I got it basically for free.

The stenciling wasn't that difficult. SI has pretty complex artwork so the only part I was nervous about was peeling the stencil off after I painted. Here was my way of doing it:
1- lay stencil down
2- I laid down multiple light paint layers immediately after each other until it was covered to my liking
3- Wait 10-15min, then start peeling the stencil up
4- wore gloves to peel the stencil as you Will get covered in paint, peeled slowly by pulling straight up or close to it, be careful with the intricate art pieces so they don't tear off the stencil, I had some small junk needle nose pliers ready in case I needed to grab a few small pieces that tore off
5 - left it for a week before i did the next layer (As the layers are rather thick, i wanted to give it enough time to dry completely, also i did this in the winter and it was a bit cooler than i'd prefer in the basement so i had a small heater running in my make-shift paint tent to keep it ~70°.)

Long story short, multiple light layers back to back over several minutes per stencil. I had no issues with paint tearing or running or anything else. The worst thing I did was a drop part of a peeled stencil on the cab as I was peeling. Thankfully, I was able to just wipe it up in the area it touched, so no issues in the end. This was all done with Rustoleum 2X spray paint. Here are the colors I used..
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For the cabinet, I broke the old cabinet down and used it as a template for the new one.
Table saw, router, a sharp pencil and some good wood glue. I got the wood from a local cabinet shop as they tend to have a nice selection of wood available and let me have some scrap they had as well for smaller stuff in the cabinet.
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Hopefully that was helpful, let me know if you had any other questions. CPR is apparently CNCing the new SI playfields right now, so hopefully I'll get my new pf before too long and I'll start a new thread in the restoration section about this whole process.

Very helpful indeed. Many thanks. It makes me feel like giving the full restore a go. I have great boards and a pretty nice playfield to work with as you’ve seen. I thought mine was bad, but yours was definitely farther gone. Mine turned out not to be as bad as I originally thought.

Todd Tuckey has a really nice restore he did on his YouTube channel so between that and what you are doing I feel more motivated to take the full plunge.

I would say that you could do it. There are a ton of resources for anything pin related on Pinside and on Pinwiki. Those two sites are where I researched the vast majority of restoration tools, techniques, vendors and parts.

I'm getting ready to pull the trigger on a SI pin, but need to know what the dimensions are, especially the width. Anyone have a tape measure handy and 5 minutes to spare?

width is 29"
length is 53.5", including shooter rod
Cabinet height is 16.5 to 19" (Tapered)
Head is 30 X 27 X 11.25 to 10" (Tapered)
I don't know the weight, other than I now it is a very heavy beast.

The head door swings open, and make sure you support the door - the neck is too weak to hold the door open for long. I put a 2X4 across the rails to support it.

Hope this helps

Great! Thanks for the info. I'm planning on picking it up tomorrow. It's a project game that I'll need to replace the worn playfield, but luckily it comes with a new overlay.

I’ve got one with an overlay and whoever did it was off a bit. I don’t know if it stretched or was off a bit, but as you go from top to bottom, the score lights are off more and more.

Make sure you spend a lot of time getting it lined up correctly, otherwise, every time you play, you will notice the misalignment.

I picked up the SI in Lexington, SC this morning. Needs a good bit of cleaning, new set of rubbers, some de-rusting and the high voltage board needs to be recapped. It came with a replacement overlay, but I'm thinking I can hold out for one of the CPF playfields, since I've read some horror stories and I'm still a rookie. Appreciate any tips ya'll can pass my way. Can't wait to get this back to Louisiana and get to work on it...

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Grats! It looks good other than the PF. Mine is a nightmare. I haven’t had much time to work on it but it’s mostly disassembled except for the underside of the PF. Needs major cabinet work your cab looks pretty solid in the pics.

The restoration of my SI is in full swing, however I have a problem that is baffling me. The game has all original boards with the exception of an Alltek Ultimate MPU board. The flippers and the solenoids are not working and I only get 6 flashes on the MPU board's LED. I've verified on the rectifier board's TP5 that the game is putting out +43 volts (actually around +45 volts). TP1 through 3 show acceptable levels of voltage. I've checked all the fuses to include the one in-between the flippers. Nothing else looks wrong. I will say that I found a ceramic capacitor that may have been clipped on one of the leads for the clone chamber target. I've soldered that back as the capacitor didn't look damaged. I have changed out capacitor C23 on the solenoid/voltage regulator board since the previous owner said the high voltage was out and had received the game with that extra capacitor that I used. Other than that, everything to include the displays, start button, sound and most of the lane switches work. Oh, one last thing is that I can't get the game to go into free play even after changing the first dip switch on the Alltek MPU board to the "1". Putting a coin in the coin slot does cause a credit to register and I can start a game. Appreciate any thoughts on what could be causing this.

Not 100% sure on the alltek, but 6 flashes means missing +43v. Check your SDB as I think the +43v comes from there and not directly from the Rectifier board.

I checked TP3 on the SDB and it seems like the voltages jumped all over the place. Eventually it settled around +108 volts.

Just picked up a SI and the GI worked for about 5 minutes before going out. All the fuses look good on the power supply board. Any help is appreciated!

make sure the +43v is making it to the MPU board. Sounds like a possible connector issue.

Check the Rectifier board to make sure you are getting the correct voltages. After that go after the connectors and replace the pins. The GI pins are always burnt and likely need replacing. Remember to replace the 0.156 with trifurcon pins

Correction, it appears that the +43 does come from the rectifier board. there is some info here https://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Seventh_flash about getting the 7th flash. Again, this is not for an Alltek but for the factory -35 board.

I'm still trying to figure out why my solenoids and flippers don't work. Today I took several readings from the different TPs on the high voltage/solenoid board and TP3 is way out of spec.
TP1 +5V
TP2 +175V
TP3 +97V
TP4 +240V
TP5 +15V
TP6 +97V
TP7 +97V

From what I've read online, TP3 should be +5V.

Any suggestions on what I should check?

TP3 connects to TP1 via a brown-green loop wire at connector J3 on the solenoid driver board between pins 13 and 25. Sounds like you've got a bad connection on one of those pins meaning you have no power to the logic circuit controlling the solenoids.

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The wire looks fine, however I’m thinking I need to reflow solder to everything pin 13, 25, TP1 and TP3 touches will fix the problem...

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Somebody's already reflowed that pin header - that's not factory soldering. Did you actually check the crimp terminals on both ends of that loop wire?

They looked good and snug. Something else I noticed was that the transistor at Q19 was clipped off, but the ends were still soldered to the board. Not sure if that would affect things. I wonder why someone would remove a transistor and not replace it...

Should I remove all the solder on J3 and re-solder it? Also the solder for Q20 looks kinda ugly. Should I reflow it?

Q19 drives the coin lockout coil on the coin door, having it cut off won't affect anything and won't cause any game play issues.

If you've got a desoldering gun then you can give it a shot cleaning and resoldering those pins. My money's on the crimp terminals though - that's usually where the problem is.

BTW, what kind of multi-meter do you have? I'm curious why you're reading 97 volts on TP3. If you were getting zero volts there I'd be telling you to temporarily jumper a wire from TP1 to TP3 as a test to see if the solenoids start working. If that 97 volts is real and not phantom, I'd be concerned.

Quench, I have a Klein Tools MM400 multimeter.

I finally received a new capacitor in the mail for C26 on the solenoid board and changed it out. Also I added some solder to Q20. I checked all the transistors at the bottom of the board (Q1-Q18) in diode mode on my multimeter and they all checked good. I found a couple of capacitors and diodes under the playfield that had one of the leads unattached, so I resoldered them as well. One was for one of the rear red targets next to the bumper cap. The solenoid on one of the small flippers had a wire that soldered it, so I took care of that as well. After all of this, no change to getting power to the flippers or the rest of the solendoids. I did notice that if I manually moved the small white flippers, it made a sound. The main red flippers did not make any sounds when I moved them. I took some power readings on the rectifier board and the following was what I found:
TP1 +7.4V
TP2 +243V
TP3 +14.9V
TP4 +.1V
TP5 +44.9V

I really appreciate everyone's help so far.

Have you worked out why you've lost connectivity over that brown-green wire at the Solenoid Driver Board (SDB) J3 connector yet?
TP3 on the SDB connects to TP1 via that J3 loop wire. TP1 is 5 volts DC power for the whole game. Without 5 volts reaching TP3, the logic circuit on the SDB controlling the solenoids has no power so all your solenoids will appear dead because the Q1 - Q19 driver transistors can't be activated.

That 97 volts you read at TP3 must be some phantom reading from your multi-meter because it's open circuit. It should read either 5 volts (presuming the connection over the brown-green wire is good) or zero volts if there's lost continuity over that brown-green wire connection. Confirm the TP3 voltage if you have access to a different multi-meter.

Just hook up a jumper wire between TP1 to TP3 on the solenoid driver board. Do the solenoids now work?

Quench, I made some great progress tonight based on your suggestion. I attached a jumper wire via alligator teeth to TP1 and TP3 and that got most of the solenoids working. When I start a game, it will kick out the ball and all the flippers work. It doesn't recognize that I drain a ball though. When I ran the self test, all of the solenoids move except 10 and 11. It also looks like at least switches 5, 17-21, 26 and 32 aren't working either.

I'll have to track down another multimeter to check TP3, so it will be a couple of days until I can run that problem down.

Cool, ok do us a favor and open a tech support thread in the early solid state tech sub-forum:
https://pinside.com/pinball/forum/forum/tech-early-80s-solid-state

The issues you're experiencing are just generic problems and not really specific to Space Invaders.
You can start the thread by copy'n'pasting or quoting parts of the below and respond to them:

Recrimp both ends of that brown-green wire with new terminals. Add redundancy to that circuit by performing the mod that ties TP1 to TP3. See the three bulletproofing mod posts #8, #9 and #10 for the SDB below which also includes ground mods for capacitors C23 and C26:

https://pinside.com/pinball/forum/topic/vids-guide-quick-bally-driver-board-repair-bulletproofing#post-592756

Don't worry about remeasuring TP3, you were obviously getting a bogus reading.

Solenoid 10 is the small coil on the coin door, solenoid 11 is the flipper enable relay on the SDB. 11 is working otherwise the flippers wouldn't work.

Switch test mode only reports the lowest switch number it finds closed. So you need to make sure all drop targets are in the raised position and you remove the ball from the game. The game should report "0" in the ball in play display. If it doesn't let us know.
Then with the manual in hand opened to the switch ID page, manually activate each switch starting from switch 40 and work your way backwards to switch 1. Report any switches not responding or switches that report the wrong number.

Thanks again Quench. I'll open up the new thread and looking forward to getting this game back in tip-top shape. This is fun and frustrating at the same time!

Has anyone run across a schematic of the playfield that shows all the part numbers associated with the various parts? I’m a bit spoiled with my Avengers and my previously owned Starship Troopers games.

Page 9 of the manual (pg13 of the PDF) has most of the pf parts listed.
Also most parts listed in the Bally parts catalog found on the Planetary Pinball site: http://www.planetarypinball.com/mm5/merchant.mvc?Screen=BOOK

Thanks for the reference. Are there other guides that break down playfield parts more i.e. thunder bumpers and the regular bumpers?

Download the Bally 1980 Parts Catalog from pinwiki:
https://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Parts_Catalogs

It has part details of assemblies and should help.

Quench, that's exactly what I needed. Great schematics that will help me disassembly and de-corrode all those little metal parts in my game!

Cool... I didn't know the Bally catalogs had been uploaded to the Wiki site. I only thought they were on the Planetary page in Flash format.
(My 2nd link was the same info/manual... you just had to drill down a little further.)

A quick update on my restoration. I permanently fixed the solenoid/flipper problem with a little bit of work on my high voltage/solenoid driver board. It was one of two things: Cleaning the pins on J3 with a fiberglass eraser or removing the old solder and resoldering pins 13-25 on J3. Now on to fixing most of my switches...

Can someone help me out and post some detailed pics of the inside of the backbox that shows the lamp wiring. I have two lamps that do not light and I'm beginning to think its a wiring issue.

I've replaced the bulbs with known good bulbs and even unsoldered the two suspect sockets and cleaned off all oxidation and tested for continuity on the bench with a bulb inserted.

Looks like I'm not getting the correct AC voltage to the two sockets which lead me to conclude it is a wiring issue.

I've highlighted in the red box the lights that are not working.

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Wiring looks correct compared to my SI. Same wires in the same locations.
Are you sure the driver is ok for that pair?
Schematic is showing that light pair as 82. Which is pin7 on the Aux J3 connector. Points me to Q20 (MCR106 i believe).
Should be just to the left of J3. Might want to give that one a check.

If that doesn't work. I would trace the wire back and make sure its not a connector issue.

I'll check out that transistor and report back.

Thanks.

Fixed. Transistors on the Aux board all tested good. Cleaned the connectors on J2 and J3 and bingo! No doubt oxidation was causing a bad connection. Thanks for the help.

You may as well plan to replace both side of those connectors - in time, you will be back to the same issue.