TAF Pop bumper solenoid not working

[strongs]

I noticed today the top right pop bumper solenoid on my TAF isn't working so it's not "popping", might have always been like this as I've only owned it for about 6 months.

I noticed it after running through all the solenoid tests.

The wires are connected to the solder tabs on the solenoid and I think the coil windings are ok (need to double check)

I'm pretty new to pinball and repairs but would appreciate any advice.

Cheers

 

[cooldan]

Get your multimeter and see if there is power at the coil for that bumper the same as the other two.

In switch test, see if moving the bumper skirt triggers the switch.

Then report back

 

[strongs]

Hi @cooldan many thanks for your reply.

Should there be constant power going to the coil all of the time? What should I set my multimeter to?

The switches appear to be working as I tested in game (the score increases when you press the bumper skirt down)

 

[cooldan]

Constant power to all solenoids at all times during the game, yes. What makes them fire is by the board supplying ground. It does this when told to by the switch, and it does it by a signal from a chip to a transistor to connect up the ground. Either the power is missing, or the switch isn't registering, or the transistor has failed.

To test the voltage, put your DMM to DC volts and put the black lead on ground (the earth braid). Then the red one to the coil lugs. Should be I think 70v (maybe 50) at both lugs of all coils.

If the bumper switch triggers a score increase then that suggests it's being registered yes, but go into the menu and switch tests to check properly.

Oh, and look to check there's not a wire fallen off either the switch or the coil, or if the switch (a funny looking spoon thing) is actually open at rest and being closed by the skirt.

You probably have a dead transistor but let's first prove the power and switch are both good, then next we will test the transistors.

It's kinda fun, and you will probably get to fix your game by desoldering and replacing a £1 part.

 

[johnwhitfield]

Keep it simple

Go into switch test. Does it register when the plastic skirt is pushed down? If not then is the switch being triggered?

If the switch is working but the solenoid isn't firing then have a look at the bottom of the bumper. Is the spring being held on properly? There is a metal yolk and a fibre top part to it. Whenever a bumper has given up for me it's been because this has broken. The spring then isn't held in place so the bumper doesn't go back up. Cheap fix (a couple of pounds), simply unscrew the broken yolk and replace with the new one. Swearing is good at this point when the spring make a bid for freedom.

Dan might be right but check this first.

 

[Jay Walker]

A simple method to check if a solenoid winding is okay and has power is to momentarily ground the return end of the coil, by-passing all the electronic switching side. But be sure it is the return tab - usually the wire is thinner than for the supply tab. On older games that had diodes across the coil terminals, it was the tab with the plain end of the diode.

With Addams, the five bumpers probably share a power feed, so, if the top right is the last in line (i.e. it only has one wire on the supply tab) there may be a break on one of the other bumpers.

 

[strongs]

Good morning @cooldan @johnwhitfield @Jay Walker

I managed to find the problem in about 10 minutes this morning.

First I checked the switches, which all checked out (as far as I could see) so then I got out my DMM and probed the solenoid tabs. One tab was giving me 70vdc immediately whilst the other I was getting mixed results, one minute I had a stable 70vdc, then the next minute it was gone.

Inspecting the tab / winding (and the bad soldering) closely, I could see that there wasn't good contact between the solder tab and the winding wire.

A quick reflow of neat soldering and my bumper "popped" into life again.

Thanks all for the advice.

 

[Jay Walker]

I'm glad that you've sorted that. It amused me that WMS made a great thing about reversing the mounting for flipper coils (so that the terminals were away from the coil stop end), but happily did the opposite with jet bumper and slingshot coils. On the older games these coils had their terminals positioned nearest the underside of the playfield, even when the jets were using the doubled-up Special/Scoring switches which came quite close to the coil terminals. I used to alter the coils of newer games to the older configuration.