The issue relates to the Aux Power Board in a Whirlwind.

F7, which is to the BR2 rectifier eventually blows after a few games. With F7 removed, the flippers and 50V solenoids still work, weakly. It appears that the 25V power supply is getting to that circuit.

I replaced BR2.

When removing F4, F5, F6 and F7, there is 25 - 36 VDC on the bridge side of those fuses, not on the 5J12 side.

I found that for it to occur, the following must be connected:

5J11-1 25V C side of the relay.

And

any one of the following:
5J5-7 3C
5J5-5 4C
5J5-3 6C
5J5-2 7C

That seems to indicate that the 25V is feeding back somehow through the Sol/Flasher 3C-3A, 4C-4A, 6C-6A or 7C-7A.

Jumpers are as follows:

W1, W3, W4.

I checked D33, D35, D39 and D41, which are supposed to separate the +50 and +25V circuits. They tested OK. But all of those would have to be shorted for each of the 3C, 4C, 6C and 7C individually to feed back the 25V into the 50V.

Using jumpers, I checked each of those one at a time. Any one of 3C, 4C, 6C or 7C connected (and 5J11-1 which supplies the 25V to those flasher) causes 25V to show up in the 50V supply.

Would someone who owns this generation system 11B that has this Aux Power Driver Board try this test for me?

Pull F7. Power up and see if the flippers work weakly. Other 50V solenoids work weakly - like a VUK does not have the power to push the ball up to the playfield.

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Would someone who owns this generation system 11B that has this Aux Power Driver Board try this test for me?

Pull F7. Power up and see if the flippers work weakly. Other 50V solenoids work weakly - like a VUK does not have the power to push the ball up to the playfield.

Thanks.

Thanks. That tells me that it is normal that the flippers will work, even with F7 blown. That means a lot.
I appreciate the help.