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STTNG flipper rebuild/frazzled coil woes

Jazzbouche

Jazzbouche

Registered
Joined
Jan 10, 2017
Messages
389
Location
Warwick
Hi all, and Happy New Year!

I have an issue with my STTNG - probably of my own making. I was rebuilding the flippers just before Christmas; left lower flipper went great and tested fine. I put the lower right together though, and when I tested it I could smell burning - lifted up the play field and smoke was bellowing out of the lower middle diverter coil. The pin still turns on, but won't start a game. I haven't looked at it since, as I wanted to cool down and look at it fresh. I assume I fried the coil and will need to replace it, but have two main questions:

1) Any ideas how I managed this? I didn't replace the eos switches (not sure if it would be those anyway?). Is it unrelated?
2) Any thoughts on what else I might've broken in addition to the coil (which I only noticed due to the smoke).

As you can probably guess, I'm a newbie at this, but want to learn and am determined to try to fix this myself. I have a soldering iron (fairly confident in my ability), and a new multimeter (haven't used one in 15 yrs+, so a little less confident). I'm still getting used to the test menu's in the pin, so please bear that in mind too.

I have time in the evenings this week to work on it while the family are away, so figured I'd ask you guys in advance so I have some pointers on where to start. I'll need to order parts, but would be good to order everything at once if possible.

Any help or advice is welcome, and thanks in advance.

Paul
 
If you haven’t touched any coil wireing then I suspect this is a random thing you are going to need a new divertor coil and more than likely the transistor that controls it the diverted coils locking on is not unknown on Sttng you haven’t remove the ribbon from the 8 driver board in the backbox when tinkering have you
 
No - not removed anything in the back box. Have been wondering if it could just be a coincidence. Does the manual make it clear which transistor is linked to which coil?
 
Had a moment to look into it this morning, and I think it's transistor Q15. According to the attached, does that make sense?

Also - this is all based off me just seeing smoke coming out of the coil - is there a way to test all this in the menu? Like a switch test or something?

Thanks

IMG_6134.JPG IMG_6135.JPG IMG_6136.JPG
 
I had a problem with this board too on my STTNG. Couldn’t find the fault. Mate used it on his Roadshow no problem. Replaced it with a rottondog aux board. Cleared fault with locking diverters. Not an expensive board to replace..

As it’s a heavy featured machine. It uses this board more than TZ or Roadshow and is a known problem on STTNG with these boards going faulty.
 
Great stuff - thanks everyone! I'll have a good look at it tonight and let you know. Will plan to order parts tomorrow - likely to be coils, transistors and fuses, then if they're still failing the whole board!
 
The tie back looks good, as does the transistor actually. Would you normally be able to see if the transistor had blown?

Coil is locked solid though! So I'll need to replace that.

Also found this fuse on the power driver assembly that looks burnt out. Assume it's linked but can't find where in the manual it would tell me!
IMG_6141.JPG
 
Ok, so looks like that fuse is for the solenoid that failed...so maybe it saved the transistor!! We'll see - might be worth replacing anyway.
 
I read this and this is what makes me worry about Pin ownership...
 
Nothing to worry about. The Aux board is only used in a handful of wide body Bally/williams machines and it’s STTNG that it commonly fails on.

I’ve replaced mine and never had an issue. Still kept the original board..
 
Thanks Kenny - you could be right! For £35 that seems like a good bit of housekeeping. Any reason why you think it will blow again though? Everything seems in place, though I get your point that I haven't solved why it blew in the first place.

Adajam4 - why the worry? I'm new to this and just throwing myself in there. Everyone on this forum is super helpful, and it's pretty logical if you take your time (cut to 45 min time when I'm pulling my hair out :) I enjoy learning how these things work, even if it infuriates me when I get it wrong.
 
Hey @Adajam4 - I am a newbie - so I bought a machine with a years warranty - Stern Star Trek Pro from Liberty games. Yes it was expensive, but piece of mind. However, in hindsight I could have saved some cash and got the same, if not better support from the good people on this forum.

I then took my life in my own hands and bought a 1979 Paragon and had it shipped over from the USA. This is a different kettle of fish as the machine of this age needs far more maintenance than the star trek pin. But, 4 months in, and I'm loving every minute, I've swapped bulbs, upgraded to LEDs, replaced lamp holders, and a new flipper coil. I've part stripped & cleaned the machine. i've taken bits off and put them back on again just to figure out how it all works. I like the maintenance side, and if that appeals to you, I'd say there is plenty of support out there, decent 'how to' guides on websites and youtube and then really nice helpful people on here, and then if all else fails, you can always get someone in to help you out. If the maintenance isn't for you, then perhaps the best advicee is to go for something newer. For me personally, I can do basic electrics, so soldering and figuring out a few wires is easy and interesting; but I couldn't for example repair a circuit board or track down the faulty component on a circuit board, but I know I could easily find someone on here who would be able to assist, or help me find a replacement part. E.g. for the 1979 Paragon, most parts and circuit boards are easily available, and swapping parts isn't generally that difficult. Hope this helps. Alan
 
^^ Everything Alan said!!

I'm similar, a newbie - just starting out and decided to try to rebuild the flippers to see how they work. Have gotten a little sidetracked with the blown coil It's all interesting though and everyone is helping with their advice! Plus as Alan said, you can always call the pro's to help out, which I have done before too and they are awesome.
 
I've done soldering etc before, i.e. repairing a guitar cabinet (speaker wiring, so not hard) and some PCB soldering, so maybe I would be OK then... It is just the enormity of it all, so much going on, I guess it's just like eating an elephant though.
 
It's definitely daunting, and i may well get out of my depth as I get further into it, but so far it's just a case of biting off small chunks. Already I'm starting to scratch the surface and understand way more than I did last week.

Still got a long way to go though
 
Quick and easy way to check which TIP122 transistor is blown - with game turned off attach multimeter on buzz setting to earth, then with the other lead touch the tabs of those trannies. A blown one will beep as the big tab will be earthed and it shouldn’t be.
 
Thanks Dan, will try that tonight. Sorry for the stupid question, but what do you mean by buzz setting? I'm still getting to grips with my multimeter.

I'll likely change the whole board given how cheap it is, but would like to test if the transistor did blow. Thanks.
 
I would trace the wiring from the coil back to the board to make sure it's not shorting anywhere, I had a fried coil and blown transistor on my old shadow when an exposed wire dangling in the bottom of the cab shorted on the cabinet speaker. I only found it after replacing the transistor and coil and it was still locking on when powered up, traced the wire back until I found the problem.
 
Hi Paul, I had exactly the same issue on my STTNG and swapped out the transistor and the coil and has been ok ever since, incidentally the transistor was not a dead short when i checked it so dont assume it is ok (must have been leaky)
 
Thanks Cursaw - checked the wires and nothing obvious out of place! Time will tell I guess.

Using Cooldans technique to test which transistor is blown - it would seem all 4 on the left side are gone (or they are buzzing at least). The right side seem fine. As I'll likely replace the whole board it probably makes little difference other than curiosity.
 
I had this problem on STTNG (diveter coil burning up) a couple of times. Did all the fixes with the tieback wire, extra diodes on the coils but it would still short out the transistors on the aux board (in a seemingly random fashion, sometimes after a couple of games, sometimes after 30+) which was extremely frustrating.

The aux board didn't hold up well to continually replacing transistors so in the end I bought the aux board linked to above and (touch wood) haven't had the problem again.

All part of the fun of owning a machine!! :)
 
Just as a quick (and hopefully final) update - I replaced the coil which had totally melted the sleeve, as well as the fuse, and replaced the aux board as suggested and it's working a treat! Whilst waiting for the parts I finished up the flipper rebuilds and also changed all the rubbers plus gave the playfield a very quick clean with novus 1, and it's playing beautifully! Got my best score yet! Now i've dismantled the gun as the trigger was sticking and am replacing the spring (which was in several pieces) and will give it a respray while I'm at it.

Massive thanks for the help everyone! It's given me the confidence to work on it further. I fancy looking at the pop bumpers and/or slingshots next! I'm sure I'll be back with new questions soon!

Cheers
 
Good work. Ayee had to replace three melted coils till we got to the bottom of fault. Should be trouble free now. Mine has. We must have had machines built on the same day ;-) I’m also having a slightly sticky ball launch trigger too.
 
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