The inside of your sockets are probably dirty, making a clear connection impossible.

Grab a piece of wire and strip a little bit of insulation off each end.

Lets bypass the lamp board and test the lamps/lamp sockets first.

Touch one side of the wire on a ground point in the machine - the metal side rail should be ok.
At a non-functioning lamp, touch the other side of that wire on the tip of the lamp socket that has the individual colored wire soldered to it (NOT the metal base side of the lamp socket).
Does that lamp come on?
If not, do the same at a working lamp to make sure the side of the wire you've connected ground to is ok.
Check all the non-functioning lamps doing this - if they all come on with the jumper wire then the problem is back at the lamp board. We can follow up from there.

You're going to have to do the exact same thing at the lamp board to try diagnosing if the SCRs (transistor looking things) that switch on the lamps are faulty - i.e. running a jumper wire to the SCRs to manually test if the SCRs are working.

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Doesn't matter. Anytime when the machine is on.

Lamp_SocketBB.jpg

Ok.
Going upstream to the lamp board, connect one end of your jumper wire to TP2 (GND) on the lamp board.
Connect the other end of your wire to the bottom right leg of SCR:
Q4 should light the roaming Saucer "G" lamp
Q27 should light the 6K bonus lamp

Click the picture to zoom in:

Lamp_BoardB.jpg

Great tutorial quench!

You got this quy!

It's probably the SCRs. Almost every Bally I get in has 2-8 of these that have gone tits up. No idea why but it's very common.

It's either the sockets, the bulbs, the connectors, or the SCRs. You seem to have exhausted everything in the chain besides SCRs.

I can help you install if needed, after you figure out which ones are bad for sure

If by "roving G", you mean the upper saucer "G", then if grounding that bottom right pin of Q4 didn't light that lamp, you have a wiring connector issue to that lamp.

Ok, now this time you are going to manually switch on the Q27 SCR.
Take the jumper wire and connect one end to TP3 on the lamp board.
Connect the other end of the wire to the top leg of Q27. If the 6K bonus lamp does not light, Q27 is faulty.

Yes it means Q27 is faulty. On your board picture the solder joints looks ok, but if you want, confirm that the legs of Q27 are soldered ok on the back side of the board.

If you look at the lamp board schematic, can you tell which SCRs drive the two spinner lamps that aren't working? If yes, run the same two tests on those respective SCRs.
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Connect the jumper lead back on TP2 (GND) of the lamp board. You need to insert the other end of the jumper wire into connector J1 pin 28 where the orange-black wire is so both wires are in there together. If the lamp lights, you probably need to re-terminate that black/orange wire. If the lamp doesn't light, there could be a break in that orange-black wire somewhere.
Note J1 pin 28 is the top most pin (the pins on the lamp board connectors count from bottom upwards). You probably need half an inch of insulation removed from your jumper wire to get it deep into the J1 connector.
While you're there just confirm (test again) that touching the bottom right leg of Q4 doesn't light that saucer G lamp.

If you think you'll repair multiple Bally/sterns this things is a great tool. Put this on the LDB and run lamp test. The board will tell you which scr is out.

http://www.pinitech.com/products/ballystern_lamp_tester.php

Basically yes. The metal thing crimped on the end of the wire that goes into the connector housing is a "terminal".
Before you do this, disconnect J1 from the lamp board. Grab your multi meter and test the continuity (with the machine OFF) of the bottom right leg of Q4 to pin 28 of J1. If continuity is no good, you have an open circuit on the back of the lamp board between those points. If continuity checks out good, re-terminate that orange-black wire going into the J1 connector housing location 28.

Awesome.

So to briefly explain how it's wired, the switched/controlled/feature lamps (whatever you want to call them) all have the base of the lamps sockets connected to 5.4V DC power via the string bare wire stapled to the playfield.
The other end of the lamp socket that has the individual wire soldered to it effectively gets switched to ground by the SCR on the lamp board. The bottom right leg of the small SCRs (known as the anode leg - you can see next to Q4 it is marked "A") basically connects to that wire leading to the lamp socket. Grounding the "A" leg of the SCR doesn't test the SCR - rather it tests that wiring from the SCR to the lamp is ok.

The top (middle) leg of the small SCRs is the "Gate" leg - you can see next to Q4 it is marked "G". Connecting TP3 on the lamp board to the gate leg manually switches on the SCR. If the respective lamp doesn't light, the SCR is suspect.

Cheers.

GREAT thread and help from Quench!!!

QUY > just LMK when you get parts in and we can get them swapped in. You can even pull the board and we can meet up for a few games of pinball whne we get it done. Super easy with desolder gun, just have to go light on these old traces.

tip...

Single sided bally and stern lamp driver boards (the SDB too) will crack the solder joints on the TO220 shaped parts just like header pins will. No plated through hole and heavy parts flexing over time leads to cracked solder joints

here is my cheat sheet for my bally lamp board test rig.
ldb pinout (resized).png

Aren’t these things supposed to stop the flicker? Maybe put a resistor on those trouble sockets.

I like that cheat sheet chart!

If it makes you feel any better, my big game with alltek has a few trouble lamps too. Had to switch them back to incandescent too.

Presume you've verified the jumper cable to the light board control lamp power is getting to the siegcraft boards ok?

Does swapping LEDs between working/non working locations make any difference?

It has been known some original SCRs can be "lazy" for want of a better term and will still cause LEDs to flicker even with the resistor load fix. Changing those SCRs can fix the issue. As a last step, try adding a 470 ohm resistor across the troublesome flickering lamp socket to give the driving SCR extra load to stay on.

From memory there were some connector issues with the wire power connector on the siegcraft boards a while back (I could be wrong). You mention these connectors are loose. If the boards don't get power then they won't serve their purpose and LEDs will still flicker, so you need to check this.

If you post clear pictures front and back of the siegcraft board so we can see which version you have, we can tell you where to measure.

Thanks. The top of the surface mount resistors shown below are all connected to the power rail as pointed to by the red arrow.
So measuring at any of those resistors along the row that arrow points to should yield about 5.4V DC when the power wire is properly connected.

BTW, you are connecting the alligator clip to the controlled lamp 5.4V power braid behind the backglass light panel, and not to the G.I or a ground braid?

Seigcraft_Power.jpg

Yep, set your multimeter on DC voltage.
Black meter lead goes onto a ground point. TP2 (GND) on the lamp driver board will suffice.
Red meter lead goes to the point where that red arrow points to at resistors on the Siegcraft board. Measure the same point on all three Siegcraft boards.

You have the alligator clip on the correct spot.

What voltage do you measure (with the red meter lead) at the braid wire where the alligator clip is hooked up to?

Hmm, not good - only half voltage.

What voltage do you measure (with the red meter lead) on TP1 of the lamp driver board? Should be around 5V DC.