LW3 VUK not working - advice, please

[Judderman]

Hi

The VUK on my LW3 has stopped working. I am looking at this http://techniek.flipperwinkel.nl/desega/ , but I also want to get more of an understanding of some basics first, and to make sure I'm reading the schematics right wrt the real world.

In the diagnostics, the VUK switch registers as on, cos there's still a ball in there, but it doesn't kick out in the coil test.

My first basic question - from looking at the schematic

The VIO-YEL wire comes out of pin 3 of J7 on the PPB, goes to the VUK, then the laser kick, then the ball launch and ends there (verified visually). I'm happy that the power is getting to the coil as the other 2 coils work.

From the other side of the coil, BRN-VIO then goes to pin 10 on J8 of the PPB (verified visually inasmuch as the wire is the right colour). Therefore, I should have connectivity between J7-3 & J8-10, shouldn't I? I don't, but that could very easily be my multimeter technique. If I should, I will try harder.

If I still can't, I will look at the BRN-VIO wire & its connections, but if I can, I'll start looking at transistors/diodes as described in the guide.

I'm sure there'll be follow-up questions.

Stew

 

[pinballmania]

Between those two points you are effectively measuring across the resistance of the coil. So you should get a reading. So check the coil. Check the thin wire is actually connected. Give it a tug. Then inspect the winding of the coil, in particular where the enamelled wire joins the tab, it can be broken where it meets the tab.

 

[astyy]

but that could very easily be my multimeter technique

Your reading of the schematic appears sound to me. I sometimes find it useful checking my "multimeter technique" on something similar elsewhere, in this case the Laser Kick is the same 23-800 coil with easy access, you can check how to read continuity and ohms (approx 5) across that so you know what you're looking for when measuring across the VUK direct across the coil and from the connector pins you've identified.

Fwiw, my same VUK plays up in Hook but typically the ball doesn't always register the switch. Probs not the same for you as you say the VUK doesn't fire in solenoid test.

Good luck with the fix hopefully something easy like loose wire as mentioned above

 

[Judderman]

Thanks for the tips - I'll try to get on to it over the weekend & let you know how it goes.

 

[Pick Holder]

I am forever replacing those TIP36s on those data east boards.
Remove the board from the game and check with a multimeter on ohms that none of the legs are shorted.
For the sake of a quid or so I would change it, also check the coil resistance - and also check it moves freely and hasnt been stuck on/burnt out/melted before.

Whilst the board is out check it for dry joints and make sure those fuse clips are tight.

 

[Judderman]

Even with much perseverance, I couldn't get connectivity, so I went to try connectivity between the BRO-VIO lug of the coil & J8 pin 10. There was a bit of sleeving round it and when I peeled it back, the wire was not attached - soldering iron out, job done.

Thanks again for patience & tips. Have ordered a few TIP36s as it sounds like I may well need them, but if I take the board out, I may send it off for a bit of more competent treatment as there is a horrible hack on the GI connectors on the power & PPB boards that need repinning.

 

[pinballmania]

Between those two points you are effectively measuring across the resistance of the coil. So you should get a reading. So check the coil. Check the thin wire is actually connected. Give it a tug. Then inspect the winding of the coil, in particular where the enamelled wire joins the tab, it can be broken where it meets the tab.

That’s what I was pertaining to above !!