hello

i have a HUO nascar
J10 is causing F21 to blow instantly as soon as i turn on the game I've tryd a few different times.
i know its J10 because I've tested the other coils.
the 4th pin on J10 looks like its a little burnt (see photos)

ive tested all coils for resistance with my DMM
all coils came back between 12 and 4.

all coils look good with no signs of issues.

the bottom jet pop bumper coil however has no diode on it (see Photos) every other coil in the game has a diode.

i took a photo of Q3 transistor as it looks different from the rest. (see photo)

also took a photo of the diode next to Q3 as one end looks like there is no solder on it at all. no other diodes on the board look like this not sure what its from. (see photo)

also took a photo of a bridge that looks a little burnt. (see photo)

i have no idea where to go from here. any suggestions?
I've already updated the rom and they changed nothing.
No coil seems to be stuck as their all in the resting position.

please help

what would the 4th pin on J10 control on Nascar? i have tryd to look it up and i can't make sense of it. The williams manual seems a lot easier to read then sterns.

also noticed metal shavings by the box in the cabinet any idea what that could be from?

Nascar photo.JPG

nascar diod.JPG

nascar bridge.JPG

nascar Q3.JPG

nascar bottom jet.JPG

nascar metal.JPG

bump if anyone has ideas

It likely has a diode on the other side of the bobbin.

i checked both sides and neither side has a Diode. The jet bumpers all worked flawlessly before this issue.

It's definitely been replaced and it connects to J10, but I wouldn't replace it yet.

I'm surprised its been replaced as this is a home use game and the owner didn't mention it at all.

in the past when i turned it on i didn't notice any coils sticking on ill check again.

that diode with no solder on one end what could have caused that? do you think that may be my issue? like i said the game hasn't given me any issues at all its worked perfectly then all of a sudden this happened.

thanks guys so much for the help!

as for the diode on the board itself thats missing solder. how does something like that happen?

also if a wire is grounded somewhere how would that happen without lifting the play field or moving the machine. no adjustments had been made before these issues.

Update!

So it's the trucker ramp eject coil. I looked at the wires going to the cable and their punched by a metal bracket on the game 4 wires total 2 for the switch 2 for the cable.

The rubber was rubbed off on the two wires leading to the cable.

I disconnected the coil and switch at the Z connector on the game turned the game on and no blown fuse everything worked except for that coil of course.

I took electrical tape wrapped all the wires plugged the coil back in and turned the game on. The fuse blew instantly.

Do I need a new coil or the wires? Or both?

The coil still reads 4 on resistance.

no the coil didn't seem to lock on at all. it just stayed dead, there was no ball in the hole to trigger the switch.

i will say i tryd before i knew where my problem was and put a ball in that eject spot and put a fuse in. the coil fired normally once and shot the ball out before it blew. that time i tryd a 4amp fuse instead of a 3amp. (i know not the best idea but i was running out of 3 amp fuses.

any idea what i do from here guys?

which side do i disconnect?

im guessing I'm trying to see if the diode is still working properly but only letting current go in one direction?

also could the wires be causing it or not because now they are wrapped in electrical tape...

thanks in advance this problem is over my head so I'm trying to keep up

ok tested the Diode and it tested good. .541 and o.L on the other direction so its stopping current one way and letting it through the other.

coil is testing good.

i know its that coil because when i unplug the Z connector to that coil it plays fine without blowing a fuse.

does stern sell the entire assembly? coil switch and wire?

Ok checked lines again put some solder on the cracks in the lines taped them back up. Now when I plug everything back in and power in I see that the coil itself is sticking on.

Q3 is the transistor for that coil and I took a photo of it above as it's been replaced before.

Is Q3 likly the issue since the coil stuck on?

If so how difficult is it to replace Q3 am I better of sending it in for work.

bump any thoughts

thanks for your input i read the same thing when searching about this issue so i purchased the newest rom and had that installed. No luck it didn't change anything.

Im thinking Q3 is bad.