(Topic ID: 264179)

Demo Man - auto launch/fire button not working


By jardine

3 months ago



Topic Stats

  • 13 posts
  • 4 Pinsiders participating
  • Latest reply 3 months ago by pinmike
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

One image has been uploaded to this topic. (View topic image gallery).

q78 (resized).jpg

#1 3 months ago

Just wondering what I do next please guys.

I have done some initial research but I'm still stuck.

I've checked the wires of the coil with no issues, even put my dmm to continuity test and got a reading. Haven't remove wrapper to check however.

Re seated J107 and J120 which are the corresponding connectors, checked Q78 as well, tested good (around 4.1v from memory). Fuse 105 no problem, not blown.

Plunger moves freely by hand so not bound up.

I've gone into test and every other coil fires no problem, except the auto plunger?!?

What am I missing please!

#2 3 months ago
Quoted from jardine:

Just wondering what I do next please guys.
I have done some initial research but I'm still stuck.
I've checked the wires of the coil with no issues, even put my dmm to continuity test and got a reading. Haven't remove wrapper to check however.
Re seated J107 and J120 which are the corresponding connectors, checked Q78 as well, tested good (around 4.1v from memory). Fuse 105 no problem, not blown.
Plunger moves freely by hand so not bound up.
I've gone into test and every other coil fires no problem, except the auto plunger?!?
What am I missing please!

Did you test the auto launch in the switch menus to see if it registers on the screen?When the coin door is open is the hi power interface knob pushed in when testing that coil in coil test?Test that transistor with a meter set to continuity,also did you pull out that fuse and test with meter?

#3 3 months ago

check button itself, had many go bad on me,not make contact

#4 3 months ago

Auto launch in switch test worked fine.

Coin door was closed while testing the coil yes, as the other fired no problem.

Continuity test on Q78 registered a buzz, tick

Pulled out fuse and tested, buzzed, tick!

Button works in switch test, yep, tick!

#5 3 months ago

Ok how about reflowing some fresh solder on those coil tabs/lugs

#6 3 months ago
Quoted from pinmike:

Ok how about reflowing some fresh solder on those coil tabs/lugs

Will try this tonight as I've got a mate who's good at that coming over.

Interestingly, earthed Q78 and didn't fire the coil?!? Have been told in the club thread that this could be the issue.

#7 3 months ago
Quoted from jardine:

Will try this tonight as I've got a mate who's good at that coming over.
Interestingly, earthed Q78 and didn't fire the coil?!? Have been told in the club thread that this could be the issue.

Yes could be and also the predriver transistor also.Its the one on the driver board small black tab with three legs

#8 3 months ago
Quoted from pinmike:

Yes could be and also the predriver transistor also.Its the one on the driver board small black tab with three legs

I've been told this as well but I don't know what to look for or what even is the pre-driver transistor?

The picture shows Q78 (arrow) that is the corresponding transistor that should fire the coil. It has 3 legs. Is the one directly above it the pre-driver?

q78 (resized).jpg
#9 3 months ago
Quoted from jardine:

I've been told this as well but I don't know what to look for or what even is the pre-driver transistor?
The picture shows Q78 (arrow) that is the corresponding transistor that should fire the coil. It has 3 legs. Is the one directly above it the pre-driver?[quoted image]

It’s the ones with small tiny black tabs
In the pic there’s 8 of them close together.you can test them with meter set to diode setting.Just place black probe on middle leg and with other red probe touch the top and bottom leg they should all be the same reading.Test them all

#10 3 months ago
Quoted from pinmike:

It’s the ones with small tiny black tabs
In the pic there’s 8 of them close together.you can test them with meter set to diode setting.Just place black probe on middle leg and with other red probe touch the top and bottom leg they should all be the same reading.Test them all

I'm gonna have to remove the board....aren't I To test from the backside.

#11 3 months ago
Quoted from jardine:

I've checked the wires of the coil with no issues, even put my dmm to continuity test and got a reading.

How many ohms did it measure? I think it should be about 5 ohms.

Can you check to be sure you have voltage to the coil? Lift the playfield. Wedge your black meter lead between the ground braid wire and the bottom cabinet so you don't have to hold it. With the red meter lead, what VDC do you measure on each of the two coil lugs? You should see about 50VDC on each coil lug.

If you don't have 50VDC to either coil lug, then you have a break in the power wire that feeds from another coil with the same thick gage wire.

#12 3 months ago
Quoted from pinmike:

Ok how about reflowing some fresh solder on those coil tabs/lugs

pinmike you won't believe this, you were right on the money!!!!

The coil wasn't firing due to a break....man!! I didn't see it but had a mate over with me yesterday that saw a spark when trying to trouble shoot.

I never saw it because of where the plunger is positioned.

Re-soldered and we are up and running.

I need to change the way the coil faces as the lugs are getting a constant hammering against the wood where the shooter lane is, which I think causes it to loosen and break over time as this is the second time we've fixed it!!

Thank you for you're help...regardless of my stupidity, I've learnt a few things along the way! Cheers.

#13 3 months ago
Quoted from jardine:

pinmike you won't believe this, you were right on the money!!!!
The coil wasn't firing due to a break....man!! I didn't see it but had a mate over with me yesterday that saw a spark when trying to trouble shoot.
I never saw it because of where the plunger is positioned.
Re-soldered and we are up and running.
I need to change the way the coil faces as the lugs are getting a constant hammering against the wood where the shooter lane is, which I think causes it to loosen and break over time as this is the second time we've fixed it!!
Thank you for you're help...regardless of my stupidity, I've learnt a few things along the way! Cheers.

Sounds great my friend enjoy!! And Cheers!!

Promoted items from the Pinside Marketplace
$ 99.00
Playfield - Other
Arcade Upkeep
$ 9.99
Eproms
Matt's Basement Arcade
$ 37.50
From: $ 40.00
Cabinet - Other
Rock Custom Pinball
$ 10.00
Cabinet - Sound/Speakers
Gweem's Mods

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside