Hello again! Subject is a 1956 Williams EM pinball machine "Super Score" (IPDB No. 2440).

I've had persistent problems with the lights. All lights are sometimes out, occasionally they come on with a little play action. Sometimes the backlights (which should always be on) are dimly lit or not at all. Seems there's a loose or dirty connection somewhere in the light circuit.

The lights are on a common 6V circuit. The 10A fuse is good. In the past I have unplugged, cleaned and reseated the connector blocks and this has solved the problem, if only temporarily. I checked the schematic and found a couple of relays (RESET and TILT) that control the entire light circuit. Burnished the relay contacts with emory paper and checked continuity from the fuse block to the relays and backlights which appears to be OK. All lights are out and nothing I've done seems to help.

I tried checking the voltage at the transformer and was not able to get a reliable 6V AC readout on my multimeter. I think I might be doing something wrong. From the 0 volt terminal I get 50V at the 50V terminal and 60V at the TAP. But I'm getting some wacky readings when I test from the 0V to the 6V terminals.

I've included a picture of the transformer. Can someone tell me where I should connect my black lead to test this?

I'm stumped on this and not sure what else to check. Appreciate any advice!

Thanks,
Brad

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Thanks for the help! Will give it a try!

Following Dr Nybble's advice I was able to isolate the fault to the electrical pathway between the transformer and the fuse block. According to the schematic this should be a straight electrical connection (no relays, switches, etc) but it does pass through one connector block. So I again cleaned the contacts with a fine grit sandpaper and reseated the connector strip. This did not solve the problem, so I've either got a problem with the connector block or an intermittent connection somewhere.

Ran a jumper from the transformer to the fuse block and the lights came on solid and have never worked better! So I've definitely narrowed it down, just need to do a little more troubleshooting.

Thank again for the help. This is a great resource for a pinball newbie.