Hi all,

I picked a Fireball classic. Game wouldn't boot and I found the F3 fuse blown.
i figured out that it came from the sound board. I removed all connectors, then plugged them in one at a time to the various different boards
in the game,
Well, I found the F3 fuse to blow when I powered on with the sound board connected.

I did a lot of digging and I am finding that at Q7 I am getting a bad reading of .187

When I pull the leg it checks good

I took a look at the schematic and see it was attached to a cap and a few resistors.

I pulled the leg of the 47uf cap and it reads 54uf so I am fine with that. The resistors also checked good.

Then we have a chip that I am not sure how to test. it is a ZN429 e-8. I am guessing at this point that it is bad. I crossed it and cannot find it for sale anywhere except ebay. I am leaning to replace it but wanted feedback. I do see that it goes straight into the 6803 chip as well.

I did see another post about this topic, but my 6803 chip is good as I have checked it with another.

Any thought, ideas?

Thank you,

dogman

I origianlly checked all of the diodes and all check good. I did not have any frayed wiring.
I will look over the entire 12 volt line.

Thank you again

I am leaning on the 4700uf. That is the first point of entry and the fuse blows immediately. I lifted out the legs of the diode D6, D7, D8 and it checked good.
I did check the 5V circuit. I did not have any bad readings. Still bothers me about the Q7 reading in the circuit but when i lifted the leg I get a good read.
Also, that is not the power section. I am thinking about just shotgunning the whole power section!

Thanks again for all your help!!

Ok, thank you for the heads up!! I will definitely do that for sure.

Craig

Npdate:

Thank you for all the help!! I replaced the (3) Tants C10 - C17 - C22 4.7uf @ 25 with 4.7uf @50 and the board does not blow the fuse and longer and the game boots. I am expericencing no sounds with the test button depressed, but i do believe that the ROMs need to be replaced. Someone that had the game before me did not have the correct orientation on the ROMs.

I was wonderiing about this! Thank you for the heads up!