My right pop bumper on Taxi went out a few weeks ago. The coil was fried, so I replaced it. The spoon switch looked ok but was not working when I put the new coil in. The switch was not closed.

Then I noticed my Q73 Transistor was burnt, so I replaced it and the fuse.

When I turn the game on, the transistor immediately gets really hot and smokes, then the F3 fuse blows on the aux power driver board, also bumper coil heats up.

Anyone know why?

Thanks

wayout440 I read in another thread similar you might know the answer, thank you.

Hi LTG there is a diode on the switch, but not the coil. Should I add one?

Also, I put the wires back the way they were before but it’s opposite of the left pop bumper. Is that correct?

Thanks for the help, I’m stumped

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LTG I don’t see any on the coils, did you see the pictures?

Do you think adding a diode would help on the new coil?

Thanks again for your help!

Thank you very much for explaining it! Dragon

I’ll keep you posted with getting it fixed

I noticed R107 that goes to Q73 appears fried. I’m going to take it off and test it.

Do you think this could be allowing Q73 getting to much voltage?

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I tested R107 in circuit and it’s appears to be ok comparing it to R101

I tested the solder points on Q73 and the right two points have continuity to the ground.

On the other transistors, they only have one solder point connected to the ground on the far right pin.

I’m not sure how this happened, anyone have any idea?

Thanks again Dragon

I'm out of town for couple weeks so I can't check anything right now.

My plan is to go ahead and order new transistors for the Q73 & Q72, new chips and sockets for the two 7402's and the 7407, new resistors for R105, R106 & R107, new zener diodes for anything in the circuit, more fuses. Hopefully then i'll have everything I might need when I get back.

I'm guessing there are a couple things damaged here, not just the Q73 I replaced.