Do you have this document?

https://www.ipdb.org/files/4116/Bally_1976_Fireball_Standardized_Test_Procedures_for_Bally_s_Home_Pinball_Games_with_schematics.pdf

Page 35 - "Trouble Shooting" looks like a good place to start...

According to the trouble shooting guide, they recommend reseating connectors... try their procedure first. Any better?

Then, if that doesn't work, page 39 in the pdf shows the GI connector coming off the power supply, connector B, pins 3 and 1... another reference on page 41 shows the wires to the playfield lamps ("13 pcs Playfield display lights") on the playfield. Is there a connector on the playfield with a pair of green wires on pins 6 and 9 (GRN, which doesn't seem to agree with their color legend on the same page) coming from the power supply?

I don't see a driver (or transistor), looks like the lamps are powered directly from the transformer.

Can you trace the wires back from the playfield lights?

Rebuild your power supply board, and connectors from the transformer, or for $60 have Steve Kulpa do it; his email is ([email protected])

http://stevekulpa.net/pinrepair/pinrepair_ballyhome.htm

GI burns up alot. I can show the repairs done the the one I have. My parents bought it NIB and it burned up the first time they turned it on. I have since added LEDs so this issue will not happen again. I was having sluggish pop bumper issues with standard bulbs. After putting in the LEDs the pops came back to life. I have series one so if ya need any reference photos just let me know.

Honestly I don't remember. I know they were all wedge sockets I believe, the pops have the bayonets. Color changers in the pops on some of the inserts and back glass. I think I did them with pinballife. It's really just a mix up lol. I have since changed to comet in other machines.

FB_IMG_1552233117279 (resized).jpg

Looks like the G.I. has a 5 amp fuse inside the transformer box too.

For LED bulbs, my friends buy from pinballbulbs.com

I heard someone was making a replacement cpu board for these. Just curious on status if its still happening?

No new news for a few years about that.

Well, there was the "Pinball Mind" cpu by "Nightmare Tony" Gonzolez, but he unfortunately passed away from cancer a few years ago. He actually had unpopulated pc boards and was most of the way finished with programming. I understand his family turned over all his work to Marco Specialties for them to finish it and bring it to market. Someone should talk to Marco and see what the status is. I had been assisting Nightmare Tony with ideas for it as well as writing some of the manual for it. I have attached a picture of the board, a pdf of the board layout, and a pdf of the unfinished manual. This board was meant to plug into the original Bally home pinball cpu board. It plugged into the original boards cpu chip socket so even "dead" original cpu boards could be brought back to life. There was plans for an "expansion" module which would have plugged into the Pinball Mind board to add modern sounds/music, knocker support, shaker motor support, lighted start button support, LCD diagnostic display, test buttons, flipper relay, and coin door support.

I also understand Ni-Wumpf is developing their own version using ARM technology. Someone should inquire about progress on it.
Pinball Mind pcb layout.pdfPinball_Mind_Manual.pdfPinball_Mind_NP-CPU002_done1 (resized).jpg

just gotta keep looking I found one that was garbage and took all the parts sold the playfield. They pop up from time to time. There was a gent on here that had tons of home models dont remember who he was. I am sure someone can find him.