Taxi
Williams, 1988Left pop-bumper is staying on. It blew two fuses and I can’t figure out what happened. Switches seem the same as the others. Was working then seemed like it magnetized for a bit and no it stays on. Is it a capacitor on the switch maybe?
After switch test...
Meter on continuity.
Game off.
Two upper connectors on right side of MPU removed.
Black probe on head ground braid.
Red probe on each of the 6 TIP-122 transitor tabs in the upper right.
If your meter indicates continuity, that transistor is shorted.
Replace with TIP-102.
It's possible that an upstream component is also crocked.
Let's see where the continuity test lands you.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://www.PinWiki.com - The new place for pinball repair info
Quoted from ChrisHibler:After switch test...
Meter on continuity.
Game off.
Two upper connectors on right side of MPU removed.
Black probe on head ground braid.
Red probe on each of the 6 TIP-122 transitor tabs in the upper right.
If your meter indicates continuity, that transistor is shorted.
Replace with TIP-102.
It's possible that an upstream component is also crocked.
Let's see where the continuity test lands you.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://www.PinWiki.com - The new place for pinball repair info
I think I did this right. Doesn’t make a sound but does change numbers. The others don’t. Is this right? I need to replace that transistor?
Also switch tests were good, except for centerbumper, wouldn’t read at all. SMH....I guess it’s what I get for taking apart cleaning, etc.
Thanks all for the help. Any is appreciated.
Q71 would be the left slingshot. Q75 is the left popper.
Does the left slingshot work?
I would run the tests again. Some of those transistor cases look a little corroded so scratch a little bit with your probe to make sure you've got a good reading.
I’ll check the slingshot. Nothing is coming up error wise. I am out of town for three days so I’ll chck when I get back also ordered some new switches for the popbumperd I case it’s the capacitors on them.
Ok slingshots are fine, replaced the pop bumper switch. Replaced transistor, it read fine but just in case. I took the brown/blue wire off of the coil and everything is fine i put the brown wire back on and it locks on. I know it’s the ground to it but I thought I would see if the others work and they do just fine, without it attached.
I did install new bumpers and connected the lights as they were. I don’t see the bumper plate touching any other wires, but can check again but I thought if that was the case I would have other issues.
What is next? Do I run a new wire, To pin 7 in the J19?
Thanks again for all of the help, ChrisHibler and @terryb.
GRUMPY the resistor? I will check it too.
Quoted from terryb:Do the test grumpy suggested.
Ditto.
Not much left to check.
You can "diode test" ZR4 just like any other diode.
The test provides a "nogo" indication...but not a "go" indication.
Compare results to the same test for ZR3 or another adjacent diode.
If that checks out...
meter on continuity.
Game off.
Black on game ground (like the side rail)
Red on the brown/blue wire at the coil.
Got continuity?
Based on what you've described, the answer will be yes. This tells you that somehow, from that point in the brown/blue wire, ground is being found. It's supposed to be found when the TIP-102 turns on and conducts to ground. I've seen wire insulation scrape off over various metal things and find ground in this way too.
If you remove the connector containing the brown/blue wire from the MPU (or interface board) and the same test =still= finds ground, then the wire is touching ground somewhere between the coil and the connector. If not, then power is finding ground on the MPU PCB.
--
Chris Hibler - CARGPB #31
http://ChrisHiblerPinball.com/contact
http://www.PinWiki.com - The Place to go for Pinball Repair Info
Thanks guys I tested the diode, it was bad, put in a new one thanks to a local repair guy who had one with him, and he showed me how to do board work, not nearly as complicated as it seemed to be. Got everything working then after making adjustments another bumper went bad, blew a fuse. Looked under the PF and a jet bumper switch had fallen apart. Fixed it put in a new fuse, worked for a second then went. Checked the diode in the circuit and replaced it.
Finally it works 100%.
Thanks guys afor all of the help. These Zenar diodes were the issue.
Wanna join the discussion? Please sign in to reply to this topic.
Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!
This page was printed from https://pinside.com/pinball/forum/topic/taxi-popbumper-stuck-in-on?hl=darcangeloel and we tried optimising it for printing. Some page elements may have been deliberately hidden.
Scan the QR code on the left to jump to the URL this document was printed from.
Sharpsburg, GA