I have a gottlieb system 3 and the flasher lamps aren't working.

I've been pointed in the direction of some resistors beneath the playfield from another forum user (thanks!) And I can I see something doesn't look right.

However I'm a bit of a noob and what I can see makes no sense to me.

It looks like maybe a resistor at r1 has been replaced and modified . Also see the ground lug at bottom of pic I think the wires in the red tape at top of image should attach here?

Can anyone take a look at the image here and help me make sense of what's going on please?

IMAG0995.jpg

Gladiators

Thanks, pal. I had it suggested that maybe because this was exported to Europe it may explain changes...

Anyone know what the lug at the bottom is for?

i actually have the gladiators manual and the board is not there. there is a 'resistor board' (A13) but this is not it.

yes, the yellow wires are soldered to the top lug. the white/green wires (4 of them i think) have been soldered to something at some point because beneath the red tape you can see. it fits the vicinity of the bottom lug also in its wiring, but as i can't make head nor tails of the thing (although everyone here is helping me drill down possibilities so thanks!), i'm reluctant to just solder it back in...

No MA part number but something on backside of pcb...actually looks like a Williams logo?

IMAG1000.jpg

Still poring over schematics...

OK, so I've been trying to find anything in schematics that could help. This is like reading a foreign language to me so I could be way off...

I found this section in the playboard schematics that sort of seems appropriate.

IMAG1002.jpg

The section showing the 67 I think shows bulbs and it lists the 'domes' here. Now flashers are also known as domes, right? If so this looks like these circuits go to a resistor R1 with .33 5w now I don't know what that means but maybe it's a starting point for me.

I'm enjoying the learning so please forgive my possibly stupid questions.

Also a full page schematic:

IMAG1001.jpg

Thanks guys for the help. I've desoldered that board above and ordered a new resistor (with a couple of spares just in case) and I'll hopefully get it all up and running tomorrow.

Fingers crossed for happy smiling flasher pics!

OK, so I made the modification and I have a partial success.

IMAG1006.jpg

All flashers bar one work as they should and the lightstrip at the back now works.

IMAG1008.jpg

The one bulb that doesn't work is constantly on as shown in pic. It also happens to be the right ramp dome and I think also flashes when you need to hit the spinner. So it comes on for two things at two different solenoids.

Can anyone offer suggestions where to start with this one?

OK, so I've tested dc voltage at lamp and its reading about 20v on lamp lug which it should be. The other lug reads .01 which is the same as other flasher lamps.

I then found some posts that suggest when something is stuck 'on' like a solenoid or flash lamp, it could be a short in a switch or just a bad switch.

Checking schematics I worked my way back to the driver board and located the corresponding mosfet at Q16, then used the guide over at pinrepair to diagnose it.

Turns out the mosfet that controls my non working flasher lamp is bad.

IMAG1013.jpg

I have now ordered a replacement part and have begun the desoldering of the bad mosfet - I have to say it's a bit nerve wracking! I've not done much soldering in the past and these components are so small...