I'd double check the fuses (off the board) and connectors on the rectifier board as well as the bridge rectifiers - start there. If one of the rectifiers went out you wont get any feature lights.

Was the game on while you were changing the bulbs? You say they seemed to work, but have almost stopped working - did they just start going out one by one, slowly, or you turned it on and half the game was dark?

Try wiggling the bulb under that right slingshot and report back - also send some pics of the rectifier board and connectors -

I’ve seen this a lot lately. Check/replace the BRs

Ok, first of all yes, that pin off the board is probably shot - you may be able to wire brush it back to life, but 2 weeks from now the lights will go out again. That plating on those header pins decays over time, especially when the wires have been stressed and overheated. That header (the collection of pins as a whole) should be replaced. Actually, ALL of the headers and connectors on these old Ballys should be replaced for reliability, there are several threads about bulletproofing these elsewhere on Pinside.

The bridge rectifiers are in the middle of the board - see that black thing sticking out? Someone replaced that one already, there are 2 more on the back of the board next to it (BR2 and BR3) - one of those is probably toasted. Test with the game OFF.

Have you tried new bulbs yet in some of the lamp sockets? Maybe at this point you only have burnt bulbs.

Swap a couple of the working bulbs over the non-working lamp sockets.

With power off, try reseating all 4 connectors to the lamp (bottom left) board and the top left connector on the MPU (top left board).

FYI. If you have new bulbs with the silver base, they are made and China and are not great quality.

I would try another lamp (bottom left) board from either Viking or FG. If another board works in HG, then try the original in the other game.

Does the original lamp board work in the other game?

You reseated this connector as well?

There's a bare braid wire stapled along the bottom playfield that connects to the base of each feature lamp socket which carries lamp power that's 5.4 volts DC.
Are you measuring 5.4VDC power at the the feature lamp socket bases where the lamps aren't working?

OK, seems like you know what the problem is. Power to the switched lamps on the playfield arrives from J1-7 of the rectifier board. It's a large solid blue wire. That wire connects to the common switched IL bus line on the playfield. There should be 6.3v DC at the common side of every switched lamp. Since some lamps work and other dont and have no voltage to boot it's safe to assume that bus has opened up somewhere on the playfield. Start with a lamp that is working and trace the bus line around. Your going to find a place where it's broken or opened up.

guess ill jump in here....it shouldn't be a hard problem.......i assume you are talking about switched illumination. you should be able to read power on the bulb socket.....if you don't have power on the socket then verify you have power out of the rectifier board. follow the line to the first lamp socket and look for a broken braid wire....if you have power, you should be able to ground a bulb at the lamp board to turn it on, using your schematics. be careful not to short the wrong pins!