Hello,

My Taxi is blowing the F4 fuse on the driver board. I recently replaced the Driver board, MPU, and Power Supply with Rottendog and Pinballpcb.com boards.

I was able to play quite a few games before F4 blew and now it blows when I turn the game on. F4 goes to J11 on the Driver board so if I leave that unplugged it doesn't blow.

I have checked all of the coils and switches and none of them are stuck or binding.

Please let me know what I need to do to fix this, I am completely lost at this point since I know it's not a board issue.

Thanks,

Jeremy

Do I do this with the power off? Also does it matter if the fuse at f4 is blown when I do theses tests? Lastly, what lug do I check and with what DMM setting?

Thanks Lloyd!

I set my DMM to 2000k Ohm symbol. Each of the coils returned a 000 result on my DMM after I unsoldered the ground wire and tested each one. I'm trying to make sense of this manual but it's not happening. I'm not exactly sure what J11 controls, but it would have to be the items that are not working (both slingshots, eject catapult by Drac, kickout hole under the spinout skill shot, and both sets of drop targets).

Thanks for the help thus far Lloyd, any more suggestions?

Yes, and even with them all unhooked it still blows F4. There must be more that J11 controls but I can't figure it out by looking at the manual. I'm very confused.

I posted this on the "other" forum and I got a reply that F4 through J11 controls J4,J5,J6, and J7 on the AUX Driver board.

I connected each (J4-7 on the AUX Driver board) until the fuse blew and my culprit was J6. I used the diode/continuity test on each pin and found that Pin 3 (free game knocker) was spiking. Unplugged the knocker and it plays right as rain. I'll replace the knocker coil down the road, it's low on my priority list.

Mystery solved, now off to play some Taxi!!!

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