(Topic ID: 193536)

TZ switch column 3 out! HELP!!!


By FatPanda

3 years ago



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  • 19 posts
  • 7 Pinsiders participating
  • Latest reply 3 years ago by Coyote
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#1 3 years ago

I was changing out a kicker switch on TZ. I powered on with the switch hanging to test it, worked great, powered off, then positioned the switch to mount to the PF. While positioning, i think i touched the switch to one of the solenoid lugs and sparks flew. Was probably within 30 secs of powering off. Now all of switch row 3 is out. Any thoughts on where to start? Im dumb with the voltmeter so any test you need me to do will have to be spelled out for me. Possible blown diode?

whysnow sorry buddy!

TIA!

EDIT: It is switch column 3, not row

#2 3 years ago

Likely you blew the LN2803, which may have blown the 12v fuse as well..

#3 3 years ago
Quoted from Coyote:

Likely you blew the LN2803, which may have blown the 12v fuse as well..

Can you explain in stupid people terms for me?

#4 3 years ago

So I see this thread that you created a year ago, but it's all Greek to me.
https://pinside.com/pinball/forum/topic/wpc-ln2803-blowing

#5 3 years ago

I'm on my phone right now, so I can't pull the schematics and point to chip references.

However, the really short and silly is that *likely* by sending +50v or +20v back through the switch matrix, the chip on the MPU was fried. This means sending the board off to get fixed if you can't do it yourself.

#6 3 years ago

This is helpful! Are there any visual signs that a chip is fried? If i pull the board, will there be burnt pins the back?

#7 3 years ago

This must be my issue? Resocket and replace the chip? Where can I get a new one?

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#8 3 years ago

Can someone chime in here on how to test the chip? That appears to have been blown in the past as that solder job is not factory.

Is that burn a symptom of sending 50v through the switch matix?

#9 3 years ago

I have a chip tester that clay reccomended that I bought on eBay for cheap and it works really well. And no, I think those burns are just prior rework.

#10 3 years ago
Quoted from pintechev:

I have a chip tester that clay reccomended that I bought on eBay for cheap and it works really well. And no, I think those burns are just prior rework.

Got a link? I can't find a tester that is denoted for ln series

#11 3 years ago
Quoted from Whysnow:

Got a link? I can't find a tester that is denoted for ln series

ebay.com link

Can’t find the exact link I used, but those one lists the ULN as supported.

#12 3 years ago
Quoted from FatPanda:

This must be my issue? Resocket and replace the chip? Where can I get a new one?

It's already got a socket, just replace the uln2803 chip and check.

https://www.greatplainselectronics.com/proddetail.asp?prod=ULN2803AP

Jon

#13 3 years ago

Theres really no way to test ic u20 on cpu board unless you have a very good logic probe,did you replace the fuse?if you replaced fuse and still no go then you have to replace u20.have that u20 ic socketted

#14 3 years ago

I have 2x uln2803 chips on the way. Hopefully it's as easy as swapping them out.

#15 3 years ago

Replaced the chip and all is good! Whew! Thanks guys!

#16 3 years ago
Quoted from FatPanda:

Replaced the chip and all is good! Whew! Thanks guys!

Good to hear!

#17 3 years ago

For future reference, http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Switch_Matrix_Problems

The Wiki has an awesome switch matrix diagnosis section.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact/
http://www.PinWiki.com - The new place for pinball repair info

#18 3 years ago
Quoted from Coyote:

Good to hear!

Thanks to you for giving me a lead on what might have been wrong! But yeah, it was socketed so easy to replace. Probably a common mishap with this machine, as the repair was already made at least once. I'll make sure to give it a good minute or two after power off before I start futzing around next time!

#19 3 years ago
Quoted from FatPanda:

Thanks to you for giving me a lead on what might have been wrong! But yeah, it was socketed so easy to replace. Probably a common mishap with this machine, as the repair was already made at least once. I'll make sure to give it a good minute or two after power off before I start futzing around next time!

It's common in ALL WPC games. Every time a switch wire hits one of those high-voltage terminals, it'll fry. I went through about 13 of them trying to knock down an intermittent issue in my game. (Turned out the Mini PF switch was shorted against the ball entry metal guide; and the right wireform ramp was shorted to 50v. So, if the ball rolled into the powerfield just right, and made contact between the ramp and metal guide, it'd fry the 2803.)

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