Hello all - I've finally decided to break out of my EM repair safety zone and try my hand at fixing a SS. I picked up a dead Stern Galaxy that I think will clean up pretty well. I've been reading a lot of previous threads on other Galaxy pins, as well as watching some youtube videos I found on repairing the pin. Hoping you guys can help direct and teach me as I learn about the SS world. Please feel free to ask me for pics or more info as I go, happy to oblige.

What I know so far:

- I don't see much wire hackery or anything strange, in fact most stuff looks completely original
- Battery was still in place, some leakage corrosion, but not anywhere near as bad as others I've seen pics of before. I removed it and started the clean-up process. Corrosion seems to be in one general "drip-down" area beneath the battery, mostly on the surface of a few components, not all over the boards, so that's good.
- Fuses are all good and proper ratings.
- Several connectors/pins look burnt/crispy, but based on what I'm seeing in other threads/videos, this is not uncommon, but clearly need replacing/cleanup.

It was suggested I do some basic voltage testing, starting with the TA 100 board and test points TP1 thru TP5. Here are the not so good readings (proper readings per TP 100 label in parenthesis):

TP1 = No reading (should be 5.4 VDC)
TP2 = 246 VDC (190 VDC)
TP3 = 14.7 VDC (11.9 VDC)
TP4 = No reading (43 VDC)
TP5 = 21.7 VAC (7.3 VAC)

Since the game isn't running, I'm guessing that might explain some of the higher voltages? The complete lack of reading at TP1 and TP4 are obviously not good.

As for what the game does, it emits a series of beeps/tones (2 short, pause, 1 short, pause, 2 longer). One display has a slight orange glow, oddly enough.

I know I have a LOT to do here, and I welcome advice/suggestions. Thanks!

Some pics... I know they're not all pretty

TP_BR_Board (resized).jpg

Head_Boards_Fullview (resized).jpg

Battery_Dmg (resized).jpg

PF_2 (resized).jpg

I don't see any activity on the LED sadly, but maybe it's really dim, I'll try in lower light. I have zero GI or any other activity aside from the sounds I mentioned, and that really dim glow on one of the displays. Should I try various other TP spots on the other boards and report back with readings?

Sounds good, rectifier fix or replacement is my first target. I'll check a few more things before deciding if all new makes more sense. Should I just unplug all the connections from the front of the board until the voltages are correct?

It appears as though the front end had some moisture issues, as I see some rust there, but not elsewhere. The knocker plunger, flipper plungers, and transformer metal parts look rusty, but everything else pretty clean. I'm told this spent some years in a campground "arcade" so that doesn't surprise me.. those are often barns I've found. Will report back soon, thanks all

Okay, so I just unplugged everything from the rectifier, aside from the bottom right plug (as it's the incoming feed from the power/power switch area). I just retested voltages, and check this out:

TP1 = 5.11 VDC
TP2 = 159.92 VDC
TP3 = 12.07 VDC
TP4 = no reading
TP5 = 10.7 VAC

TP1, TP3 and TP5 all look a lot better (though TP5 is still a little high), but TP2 went down and TP4 is still no reading.

Thoughts? I'm curious why unplugging the other connectors from the rectifier would actually cause the 5V to reappear.

I found the fuse holder for the 190V section was dirty. Cleaned it up, which stabilized all the readings, but they're still off.

TP1 = 8.1V (too high)
TP2 = 174V (bit short of the 190V)
TP3 = 11.92V (perfect)
TP4 = no reading
TP5 = 10.7 VAC (still a little high)

I'll go over it all again, but I'm leaning towards a new board. This one is pretty beat and flaky.

I checked the TP4 fuse and tested it, it's the proper rating and isn't blown. Tested in-place too on the fuse holders, good connection there as well. So it's probably the bridge like you said. But yea... new board looking like the smart move.

Board ordered, along with a bunch of connectors/pins/etc so I can work on changing those out too. Maybe I'll get lucky and the rectifier is the source of the game's issues ha. I won't hold my breath on that, but here's to hoping.

While I wait for the rectifier, connectors, etc, anything else board-wise I should dig into, or just sit tight for a couple of days while I wait?

I figured I can always work on the old one and repair it in my spare time. It will likely come in handy one day, and good to practice on. Or someone I know will need/want it I'm sure.

I hate waiting for parts. Maybe I'll do some tear down and clean-up in the mean time... though I do prefer waiting until it's running before going too crazy. I see PBR doesn't have full flipper rebuild kits for this, so that stinks. In particular I really need a new plunger and link... which they don't have. Time to hunt.

Would the LED turn on if the voltages out of the rectifier board aren't right? I would think that would cause things like the MPU to not function, LED included, right?

Pinball life sells full brand new stern flipper mechs and all the parts in them.

Thanks - I'll check that out

As suggested, pulled the MPU and Lamp Driver off to take a look. See pics for reference. The Good news is that the Lamp Driver looks good on the back. There are components that have corrosion/leakage on their surfaces, and a little on the legs, but I think all of this will clean-up alright, so Lamp Driver should be okay I believe (tell me if you think otherwise please).

The Bad news is the MPU is not looking great. Reviewing the back, the damage looks a little rough, but I'm new to this kind of corrosion, so I welcome your thoughts. Some of those traces look pretty eaten up. The corrosion is in more places than I expected, as seen in some of the photos. Honest opinions - is this a clean-up and save it situation, or am I in some trouble here?

Lamp_Driver_1 (resized).jpg

Lamp_Driver_2 (resized).jpg

MPU_Front1 (resized).jpg

MPU_Back1 (resized).jpg

MPU_Front2 (resized).jpg

After chatting with a few folks, I think I'm going to go the route of replacing the MPU, and then in my spare time working on the old one to see what I can do with it (and learn on it). I've done some board work in the past (cap kits, resistors, a few sockets, etc.) so I don't mind giving it a try when time permits. I'd rather spend the time working on the game in other ways, assuming I get it up and running. Hopefully the new rectifier and MPU (and new connectors) will sort out most of the issues.

While I wait for all the parts, I'll continue checking/cleaning other stuff. More to come... thanks all.

When I first attempted to boot it up, I got the double tap tone, then a single tone, then a longer double tap. No other signs of life though. Given the wacky voltage readings at the rectifier, I'm surprised I even got what I did.

After cleaning all the fuse holders, which brought a few of the voltages closer to spec, I tried again. No tones anymore, just speaker hum. The 1st player display showed about 1/2 of a single digit lit up, which was odd. That was literally the only thing that happened. Attaching pic for kicks, since it's the most I saw in terms of life to date.

After all that, I decided to go with the new rectifier, and based on feedback, I'll be picking up a new MPU. Turns out the place selling them is literally 30mins from me, so I'll hopefully pick them up tomorrow and have a chance to try things out tomorrow afternoon or evening!

First thing will be to hook up the new rectifier and get some solid (and hopefully correct) voltage readings. Then we'll go from there.

Galaxy_1stPlayer_Score (resized).jpg

The plungers are rust covered on the existing flippers, along with some of the other bits and pieces associated with them. It's one of the only areas that has that issue, which is strange. I'm guessing I'll need to rebuild and/or replace them entirely, but I'll worry about that once the machine is alive again. I've already got a growing "to be ordered if it lives" list haha.

Washed the board with vinegar solution as suggested to neutralize corrosion. Dried with compressed air (and left for more drying overnight). Did some testing on the damaged spots, and surprisingly traces that looked rough all test okay. Cleaned up a couple sockets and tested through okay too. I'm sure the quality of the connections aren't great and could cause issues for sure, but I was honestly surprised so much was testing okay path-wise. Looks like this old MPU will be worth working on eventually.

Hopefully picking up the new rectifier and MPU today. I did notice that the TP4 and TP5 on the new rectifier are swapped in terms of marked voltages. My existing TA-100 Ver B has them TP4 43VDC, TP5 7.3VAC, but the info I'm seeing on the new board shows them the opposite. I'll have to be careful of that with wiring up the new board.

Wouldn't that alter my connector pinout too? I need to be careful and check this out a little before hooking anything up.

Okay, new boards picked up. I soldered on the new rectifier and did a test with just the transformer's AC hooked up as suggested (Pins 6 & 7 on J2). All my voltages look good on the Test Points!

I checked my TP1 at the Solenoid Driver as well, and it's showing 5.10VDC, so we're good there.

I was going to install the Alltek Ultimate MPU, but I'm having trouble. Galaxy has a Sound board on the left side, mounted to the side of the head. It's in the way of the two connectors on the far left side of the Alltek board. They're set further to the left than the original MPU-200, it's annoying. I'm assuming plenty of people have installed Alltek MPUs in similar games - did they relocate the Sound board? Change the mounting holes on the bracket for the MPU? Seems like a hassle either way. Anyone dealt with this?

Still need to figure out the above board-mounting issue, but I got it hooked up temporarily to test and... IT LIVES (sort of)!

Got a full boot up with tones and lights, sound working, insert lights rotating through/flashing in attract mode, and head GI nice and lit up. Displays are on, see pic, not sure if this is normal for them to sit there displaying all zeros.

None of the credit switches do anything. When I pressed the credit button, it sounded like the outhole kicker attempted to fire, and the background sound of a game in play started, but nothing else happened. Playfield dead, flippers dead, ball didn't kick out.

But hey... this is a big overall improvement. Thoughts on what's next?

Galaxy_Lives_1 (resized).jpg

Galaxy_Lives_2 (resized).jpg

Here's the Sound Board issue in terms of space. The sink at the bottom and caps run into the lower connector on the MPU if I try to mount everything as it's designed. Even the way the bulk of the wires are run gets in the way, it can't fit back in the corner between the boards. (Note: wires are all removed from various tie-downs and such because I needed to move them out of the way to get the MPU installed. Normally they're crammed into that corner running up the back of the head)

Also, a pic of the Player 2 display from the back... I think I see a small issue there haha.

Sound_SpaceIssue (resized).jpg
Display2 (resized).jpg

I took a quick video of the displays during overall burn-in self test mode (also ran the display-only test, same result). Looks like P1 display is hosed as you said. P2 display bottom row needs fixing. Rest of the displays all look good in the test I believe.

- Light test seemed good (aside from lots of burned out bulbs).
- Solenoid test I can hear some stuck/not firing, but most of them did, so that's good.
- Switch test showed a "4" on the display, which if I read the manual correctly means I have 4 closed switches and the rest are open. Not sure if I should have any closed or not? Maybe the outhole with the ball there, if it's included in the count would be one... but is 4 good or bad there?

Video of displays during test

Edit/Update - Game sat in attract mode without issue for a while (easily 5-10 mins) while I checked a few things. Now it seems to randomly reboot, enter attract mode, then reboot again 10-15 secs later. Sometimes it doesn't even fully boot before rebooting. I checked the voltage on the solenoid driver board... holding steady at 5.10 VDC.

No, so far I've only replaced the rectifier and MPU.

Per the above I'll check the 12V and test points on the MPU next

Thanks in the switch explanation, I'll check that a as well

Yep, all original. Guess I'll rebuild that board with a kit next.

Okay,will do. I picked up a bunch of connectors from a localplace, but of course they were out of the connector sizes for the ones you just mentioned, so I don't have those.

Went to order the AS-2518-22 rebuild kit from Big Daddy, but he's running a $100 minimum right now, ouch. Is there another source for these caps/kits? I've been googling, and I can find the 15000uf/35V snap-in one at Digikey/Mouser/etc. Struggling with the other (150uf 350V or 400V, axial). Found one at Mouser, but for $17, which seemed odd.

Advice welcome on a good source for the kit that I may have missed in my searching (my brain hurts) thanks

It's working! I did a bunch of testing and something seemed fishy with the connections coming off the rectifier. I had not repinned them all yet since it had booted fine with the existing connectors. Bonehead move. I just repinned and used new connectors... Game booted right up, credit switches work, game started and scoring, flippers, etc all work.

Tons left to do, and I'm still going to rebuild parts of the solenoid driver, but this is awesome. More to come, thanks all

I'll be reflowing displays first thing in the morning. Then doing all the connectors I have handy. Just ordered the caps and other stuff from GPE, flipper rebuild kit and other parts from pinball life. I have a parts order going to PBR too, so I'll hit them for some stuff as well. Lots to work on, I appreciate all the help, I'm sure I'm not out of the woods yet.