I've repaired a WPC driver board with blown fuses and transistors and also traced back from Q50 to the coil it powers, solenoid 13 "Lower Jet Bumper". Checking the resistance on the coil shows 0.5 ohms unlike the neighbouring Jet Bumpers which read 10.3 Ohms. I believe that means the coil is bad?

This might be a bit of a silly questions, but... how do you actually remove the coil? As the image below shows, there's a plate that's holding it in place, but the jet bumpers all appear to have extra long screws which prevents the socket reaching the nut. Are screws this length normal on williams jet bumper coils?

Can the plate screws be accessed from the top side of the playfield if I remove the bride helmet, various plastic parts and the bumper top? As that's quite a lot of items to remove, I'd rather not do so if the plate screw isn't actually accessible there.

Anyone have this machine? If so, is there an easy way to remove this coil that I'm overlooking? Or does everyone just buy a socket set that's extra long to fit over these screws?

pop_bumper_screw_length (resized).jpg

Thanks for the help. Saved me a lot of hassle.

The two yoke nuts were quite easy to get out but the two Philips screws were quite tricky. Due to their location and not having a right angled Philips driver... I might have to buy a suitable tool for that.

Managed to get them out in the end although the coil was quite adamant it was staying in place and would not slide forward at all. The plunger is stuck fast at nearly full extension.

With a bit of fiddling around I managed to work the coil out. I expect the two Philips screws to give me more grief when putting the new coil in though

The coil to the bottom right looks far more accessible, why couldn't that would have gone instead. That said, the coil to the bottom left looks even worse, the two Philips screws are blocked by the head casing. Not sure I'd have got to those at all

Yes I have a destroyed transistor, well two and a resistor in the Q50 section. Those were the first parts I replaced along with fuses, but figured there must be a reason they were damaged which led to the coil. Hopefully when I power on that was the one and only reason

I have ordered a sleeve yes, in fact I've ordered a full set as I plan to go through all the coils before long to check the current wear. I know these haven't be checked by the previous owner so they've had 25+ years of usage on them.

I don't believe they did any maintenance unless you count melting the left ramp with a soldering iron to try to repair a split plastic and screwing in three screws to the right hand side of the heart ramp entrance where the plastic had also broken I'll deal with those somehow when I disassemble the playfield to give it a decent clean as it's quite filthy atm.

We've three sets of nut drivers and whilst all the sockets are hollow for them and do fit over the screws, they're so long they go right through the socket and out the other side. The other side where the square part of the handle pushes into the socket is then blocked. I think I'll just have to get either an extension/extra deep socket if I ever have to remove the entire mount.