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Star Trek Coils Problem

Judderman

Judderman

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5Years
Joined
Mar 28, 2016
Messages
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Location
Cheshire
Hi

At the Northern league meet on Sunday, a ball went into the left eject on my Star Trek Pro, and it flashed up an error saying it had malfunctioned. We checked all the fuses that looked dodgy, but they were OK. The general consensus on the day was that it was probably my rectifiers. Tonight I ran the diagnostic coil & none of them work, but the flashers flash. They do try; for instance the flippers & pops move slightly.

Is rectifiers still the likely culprit? Open to diagnostic ideas.

Stew
 
AlanJ said:
e you getting the correct voltage at the flippers?
Click to expand...
Hi Alan - only just got round to looking at this - I'm only getting 22v (measured between one of the coil lugs & the earth braid - is this the right test?). Have a feeling it should be 50.
 
AlanJ said:
Low, so check the voltage at the psu/rectifier. it’s pointing to that
Click to expand...
Cheers - did some more digging between other things I needed to do - checked the voltages on this connecter

1679264529869.png

Got these values, so some of them are way out.

1 - 7.9
2 - 10.5
3 - 10.5
4 - 0.38
6 - 15.3
7 - 0.18
8 - 18.2
9 - 5.8

Out of the transformer, they appear to go into this plug with the non-yellow wires - does that look like I've identified the right thing?

1679264832649.png

I'm assuming that if I tested at that plug, I'd get the same values, but looking at the transformer, it just looks like random wires coming out of a brown paper package (neither tied up with string, nor my favourite thing) - a bit stuck as to the next step here.

1679265048030.png
 
id be amazed if it was the transformer I mean its possible but feels unlikely - have you checked J8 on the power board? Have you got another SAM game with a power board? @myPinballs knows these boards very well.

also the premium has an aux board that I don't know if the pro has but I'd check that also.
 
Change the coil
Change the mosfet

Dont just do one of them.

Sorts out the issue most the time

NB - sorry - I did not read detailed enough.

Check rectifiers and capacitors. I have had the capacitors fall off SAM boards.

You need a decent heat controlled soldering iron to repair these boards.

Also check the tracks under the PCB as I have known a couple of those to literally burn off with a shorted coil. i.e the PCB track becomes the fuse.
 
Last edited:
Your transformer is unlikely to be the issue. i fear you have mis-measured. that’s the good news. Meter on a/c across each pair of outputs. eg across 2&3 should give 19v.

the issue much more likely the rectifier section. bridge rectifiers & caps
 
Transformers hardly ever go wrong, most reliable pinball item!

Bridge rectifier is most likely the issue if a set of coils are dead, mosfet/coil/wire off if just an isolated coil not working , though a fuse will most likely have blown if it is a rectifier shorted. Are you sure the fuses are ok? Did you take them out from the related circuit to check? Don't test in board.

Can send me the board and i will test here in a separate game and fix if an issue if you don't want to do it yourself/ not confident

Fixed a lot of sam games!
 
Cheers for the suggestions guys - nothing on J8/9, but then I checked ALL the fuses, not just the likely culprits that we tested during the meet, & F5 had blown. Replaced that & all working again.

One last thing, the fuse I replaced was white rather than clear; is there any significance to this?

Stew
 
Judderman said:
Cheers for the suggestions guys - nothing on J8/9, but then I checked ALL the fuses, not just the likely culprits that we tested during the meet, & F5 had blown. Replaced that & all working again.

One last thing, the fuse I replaced was white rather than clear; is there any significance to this?

Stew
Click to expand...
doesn’t matter. Important things are correct amp rating as per manual and anti surge rating
 
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