Hi everyone,

I have a neglected HH which I am trying to get up and running. I have had all the boards checked and repaired, repinned the connectors, and done the ground mods. I have connected J1 only on the power supply and the voltages are all good. I'm now checking the coil resistances before putting all the other connectors on the boards and powering up. All coils are above 2.4 ohms, except for:

1. Main playfield lower pop bumper resistance: 1.9 ohms, disconnected 2.0 ohms, with diode cut 1.2 ohms
So I guess this coil is bad?

1. All 4 main playfield flippers resistance: 1.5 ohms
I disconnected one of these and get 3.5 ohms
What does this mean?

Desoldered the wire from one of the lugs.

Just that one.

Thanks for posting that chart.

Actually, the pop bumper coil is an A-4893. It's the only pop bumper with that coil and, looking at that chart, the resistance is about right, so I guess it's ok.

I removed the ground wires from the left lug of the flipper coil, the EOS is still connected.

The upper flipper coils give a different (higher) reading when connected and Clay's guides says all the coils should be over 2.4 ohms, so that's why I'm thinking there might be a problem.

These are all A-17875, on both the upper and lower playfield.

I just did some more testing:

On the upper playfield flipper coils (which are still connected), I'm getting 3.2 ohms.

On the lower playfield, I'm getting 1.6 ohms on all 4 flipper coils.

When I disconnect the ground wire from one of the lower playfield left flippers, I get 2.9 ohms at both the disconnected flipper coil and the other left flipper coil which is still connected. Does this tell us something?

Is their anything else in the circuit which could be causing the low reading?

Is this normal?

Can someone please put the leads of their multimeter on the outside lugs of one of your main playfield flipper coils and read the resistance for me? You should be able to do it through the coin door, don't even need to lift the playfield.