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Short error on Taxi

crsedgar

crsedgar

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Joined
Jun 12, 2016
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DUNDEE
Getting Taxi ready for a league meet and Pinfest and it has an intermittent short on WHY-YEL row 4, 95% of the time the short is present and I've not identified what I did to suppress it.

I'm unsure how I should approach troubleshooting the issue any pointers would be greatly appreciated.

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Pick Holder said:
The short is to where ? Another switchline? Ground
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Hi Phil thanks for the reply.

I can't get a continuity buss with the ground braid (machine off) to the leaf switches if that's how I would determine if it was a ground short.

When the machine powers up it fires a few solenoids.

When I close the right ramp exit switch the left the left jet bumper fires if that helps narrows things down any?
 
Chris I will be working on a DE board soon, I will be making a test rom to bench test the board, should you need to hook your up let me know, that's if it's a board fault
 
Its looking like a board issue, I removed J8 AND j10 and tested the switch matrix with jumper wires and the short is showing up on the screen plus the same slingshot (left) is being triggered by that exit ramp switch.

I'll take the board out and test the transistors etc...
 
As I said I have the test rom Chris and a psu rigged up here to test it if needs be?
 
ronnie63 said:
As I said I have the test rom Chris and a psu rigged up here to test it if needs be?
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Okay mate didn't realise you had the test bench already setup, that's a great offer if you want to PM me when would be convenient to you that would be braw.

Cheers
Chris
 
crsedgar said:
Okay mate didn't realise you had the test bench already setup, that's a great offer if you want to PM me when would be convenient to you that would be braw.

Cheers
Chris
Click to expand...

No worries Chris, it's nothing fancy, just a pc power supply rigged to 5 volts, I'm fairly flexible Chris. here most of the time
 
So it appears that pulling the CPU board out onto the test bench and reseating some components has resolved the short, Ive turned the game on 5 items now and no short and for the most part the games plays fine albeit a couple of issues.

While testing the game I noticed that none of the pop bumper solenoids were firing, F3 on the aux power board had blown, I'm unsure if I should just replace fuse and fire up the pin or I should do some further tests to eliminate any possible board damage what would you do?

Other issues spotted the left lane change is not working ONLY the right works just now and a string of the GI is out on the backbone.
 
Replace the fuse and see what happens - the fuse is rated so nothing of consequence will fail as long as it is the right value. Check the latter, many a story where an overrated fuse was used.
 
And lane change on taxi comes from cherry switches on flipper buttons I think so should be dead easy to fix. Probs just needs adjusting
 
So popped in new fuse at F3 and switched it on and the left pop bumper solenoid locked on, I quickly switched it off and have now disconnected that pop will investigate after the pinball league meet this Saturday, possibly a shorted resistor/capacitor at the switch itself.

I replaced the cherry switch on the left flipper and the left lane change is now working.
 
crsedgar said:
So popped in new fuse at F3 and switched it on and the left pop bumper solenoid locked on, I quickly switched it off and have now disconnected that pop will investigate after the pinball league meet this Saturday, possibly a shorted resistor/capacitor at the switch itself.

I replaced the cherry switch on the left flipper and the left lane change is now working.
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More likely a blown power transistor, if it locks on as soon as you power up the machine
 
Yeah I had one lock my pop bumper on. It was its maiden voyage after it was restored. Thankfully Will Barber saw it and just stood there and said “ha, look at the smoke coming outta that taxi”. So that was handy 🤣
 
It does sound like a locked on driver Chris not sure I don’t think they were on the special solenoids? Maybe the switch is stuck closed? Test Ron might help this time lol
 
Taxi was one of Williams' final games with 'Special' switches, simply for the Jet bumpers - slingshots had already changed to normal 'matrix' switches and a '3rd stage' drive transistor on the Aux Power board.

Try it with the Special Switch connector detached; if the bumper doesn't then lock On the drive transistor may have survived, if it still does then it hasn't. But as Alan points out, a special switch shouldn't be able to operate the solenoid until a game is started, so locking on immediately points towards the transistor being blown.

If the Taxi is played with the bumper not working, a Test Report will advise "Check Switch 17, Left Jet Bumper". That's the 'scoring' switch, which won't have been seen with the bumper out of action, rather than the 'special' switch which operates the bumper.
 
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Jay Walker said:
Taxi was one of Williams' final games with 'Special' switches, simply for the Jet bumpers - slingshots had already changed to normal 'matrix' switches and a '3rd stage' drive transistor on the Aux Power board.

Try it with the Special Switch connector detached; if the bumper doesn't then lock On the drive transistor may have survived, if it still does then it hasn't. But as Alan points out, a special switch shouldn't be able to operate the solenoid until a game is started, so locking on immediately points towards the transistor being blown.

If the Taxi is played with the bumper not working, a Test Report will advise "Check Switch 17, Left Jet Bumper". That's the 'scoring' switch, which won't have been seen with the bumper out of action, rather than the 'special' switch which operates the bumper.
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Thanks Jay awesome response.

The test report is indeed picking up the left bumper now that I've disconnected it.
 
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