Wobbly Wells Gardner - 19k7414

Have you got another arcade power supply you can try?

Disconnect the degaussing coil (not sure if correct term for it) thing from the chassis?

Disconnect the degaussing coil (not sure if correct term for it) thing from the chassis?

 

Yep, try this first. The posistor component that shuts off the deguassing loop can degrade over time and the shocks from moving it can cause it to break up, which can cause this. You'll find a thick black taped up loop strung around the wide body of the tube, two wires come out of this and will connect to the monitor chassis, very close to where the mains input wire is. Just unplug the loop at this connection.

Thanks all so far. I did swap out the power supply no change. Degaussing was a good suggestion and I thought you guys were on to something when I saw that a heap of crap switch had been bodgied into the loop. Pulled it from the board. Sadly no dice.

 

The unit itself looks pretty clean. I've given all the pots a bit of a wiggle and all have behaved like you would expect.

 

Any other suggestions before I pull it?

I'd check your video ground connection next, from the board edge connector to the monitor. Normally things are much worse if that is totally missing, but as so much of the image is black it is possible the degree of interference cause by a floating ground may be less than normal.

Thanks again. No dice. Clipped the grounds on the jamma to the monitor chassis. No difference.

@bcg. Your last resort will be the yoke on the tube might have loosened while in transit.

Can you post pictures of the yoke pls and check if it is loose.

Thanks dragonlee. Did give it a good wiggle before I asked on here. Seems ok to me.

 

 

Given all the connectors a press in and a wiggle while it's on and running. Still no joy.

 

Thanks everyone for their suggestions. I'm wondering if that big filter cap is wobblier than it should be. Might be time to discharge the tube and pull the damn thing out.

Thanks dragonlee. Did give it a good wiggle before I asked on here. Seems ok to me.

 

https://www.aussiearcade.com/attachment.php?attachmentid=156966https://www.aussiearcade.com/attachment.php?attachmentid=156965

 

Given all the connectors a press in and a wiggle while it's on and running. Still no joy.

 

Thanks everyone for their suggestions. I'm wondering if that big filter cap is wobblier than it should be. Might be time to discharge the tube and pull the damn thing out.

NO..thats the chassis..Im referring to the yoke on the tube which has the red/blue/green/yellow connected to chassis.;)

Best drop Jomac a PM, he'll be able to tell you what next to try.

NO..thats the chassis..Im referring to the yoke on the tube which has the red/blue/green/yellow connected to chassis.;)

 

Of course. Brain wasn't on. Will take a look tomorrow when the machine and I are in the same building again.

Thanks again Dragon Lee. Yoke appears to be on correctly. Checked the correct earth this time. There is the earth which runs to the strap around the back of the tube, then to the tube driver then down to the video chassis. Checked earths there against the Jamma board. All seems in order.

Geez it does look like a degauss problem as mentioned earlier. Some of your plugs don't look seated properly including the one on the neck board with the blue wires. The video connections plug on the left looks a bit dodgy too.

Geez it does look like a degauss problem as mentioned earlier. Some of your plugs don't look seated properly including the one on the neck board with the blue wires. The video connections plug on the left looks a bit dodgy too.

 

Yeah I reseated them as well after taking the photo. The degauss wiring is completely disconnected. I'm out of ideas - thanks for you help. Will pull the board and start looking at components and joints.

Seen this with bad yokes.....

Hey.. has anyone suggested moving the cab? Could be interference. Worth a shot. :) And cheap to try.

Finally got back to it. Yep, driest solder joints I've seen on C55 - that big filter cap on the back.

 

Thanks for everyone's suggestions.

 

 

- - - Updated - - -

 

Might want to put that degauss circuit back together now :-) But she's a much happier camper than before.

 

So that filter cap might be at fault if you see a wells gardner behaving like the degauss is buggered.