STTNG - help with 8 driver board issue
tony holdgate
lower divertor).
Originally it was a fried coil and Q15. I replaced both but on test the fuse
blows and cooks the transistor.
I have read up (googled and Clay) and checked the tieback wire. At this
stage I haven't added a second wire but checked continuity from the coil to
the 50V pin on the board- it's ok. I have also added a diode only to the
lower divertor coil at this stage to try and isolate the issue.
I haven't replaced the pre-driver transistor as it tests ok (on the board
via the rough method)- and it tests the same as the known working ones on
the board. The upper divertor, up and down drop target work fine on the
test - only the lower divertor blows the fuse. There is damage on the board
where this transistor is mounted and I've had to add jumpers to get around
it. Also as I didn't have a new coil ,I've used a second hand coil of the
same type - but it measures out at about 6 ohms and I am presuming it's ok.
Any help appreciated
Cheers
Tony
(CARGP18)
Jelle Nelemans
Did you replace the Q15 with a TIP102 ? or with a substitute transistor
I know some substitutes have almost the same specs except for the max
current (tip102 100v, bd 926 70v) this is in some cases not enough.
Some traces were bad on the Q15, is the predriver-trace to transistor intact
?
Does the diode and the resistance on the 8-driver board measure good values
?
Does the diverter move smoothly, is it not binding and thus frying your
transistor.
The 6 ohms on the coil should be enough, but you can also exchange the two
diverter coils and see if the same Q15 blows or that it moves to the upper
diverter Q16
I strongly suggest you put a tieback in place, so the spike current between
those 4 coils involved in this cirquit, is properly diverted and not spikes
back to your transistor.
--
Jelle Nelemans - The Netherlands
________________________________
Speak*Easy-4 (1982)
Trans*porter: The Res*cue(1989)
BS Drac*ula(1993)
W*H2O(1993)
S.T:T.N.G.(1993)
Pin-site : http://home.wanadoo.nl/jellen/
________________________________
"tony holdgate" <tonyho...@hotmail.com> wrote in message
news:411f04bf$1...@dnews.tpgi.com.au...
Roy Fash
this be done on all STTNG machines?
Thanks,
Roy
"Jelle Nelemans" <jel...@wanadoo.nl> wrote in message
news:411f405f$0$148$1b2c...@news.wanadoo.nl...
> Hi Tony,
Jelle Nelemans
follow the url to Clay rapair guides:
http://www.marvin3m.com/wpc/index3.htm#odd
Scroll down until the topic:
Problem: Star Trek Next Generation diverter coil stuck on!
There it will explain the problems you can encounter when the tieback break
or is absent.
Original there *is* a thin violet wire in place for tieback (look at the
picture in the above mentioned URL)
But it has the tendency to break lose, so a back-up tieback with heavier
gauge wire is recommended.
You can place that backup wire on every of the four coils (power lug)
involved in that circuit. (upper- lower diverter coils and the two coils on
the drop-target assembly).
--
Jelle Nelemans - The Netherlands
________________________________
Speak*Easy-4 (1982)
Trans*porter: The Res*cue(1989)
BS Drac*ula(1993)
W*H2O(1993)
S.T:T.N.G.(1993)
Pin-site : http://home.wanadoo.nl/jellen/
________________________________
"Roy Fash" <roy...@prodigy.net> wrote in message
news:p0JTc.3031$Y94...@newssvr33.news.prodigy.com...
tony holdgate
>
> Did you replace the Q15 with a TIP102 ? or with a substitute transistor
> I know some substitutes have almost the same specs except for the max
> current (tip102 100v, bd 926 70v) this is in some cases not enough.
Tip102
> Some traces were bad on the Q15, is the predriver-trace to transistor
intact
Yes
> Does the diode and the resistance on the 8-driver board measure good
values
The diode is ok but I haven't checked the resistor - will do
> Does the diverter move smoothly, is it not binding and thus frying your
> transistor.
Yes - I stripped and rebuilt it
> The 6 ohms on the coil should be enough, but you can also exchange the two
> diverter coils and see if the same Q15 blows or that it moves to the upper
> diverter Q16
Here's where I think the problem may be. The coil in the machine is a
SA2-23-900DC where the manual calls for a AE25-1000. I'm guessing that this
means the coil in place has a lower resistance (900 winds vs 1000) and this
may be causing the problem. However the both coils do measure out almost the
same. I've ordered a new coil.
> I strongly suggest you put a tieback in place, so the spike current
between
> those 4 coils involved in this cirquit, is properly diverted and not
spikes
> back to your transistor.
I found the tieback and checked it for continuity to the board- it is in
place but on the up solenoid - not the down as in your picture. I will add
another but I'm still in troubleshooting mode.(get it working first).
However doesn't the 50V+ LED on the board indicate that the tieback is in
place?
I am going to replace the coil, tip102 and the 2n4403 in one go this time.
When this transistor goes, it is with one hell of a bang and I am concerned
I'm going to damage the board more. The last time it blew it knocked a hole
out of the transistor itself which does suggest a dead short.
No parts for about three days so I'll have to park it. Any other suggestions
welcome
Tony
CARGP18
tony holdgate
has had more hacks than ER so I presumed the worse.
Anyway whilst waiting for a new coil I used a known good used coil close to
the right type. When it blew the hell out of my repairs I presumed it was
just not close enough.
I came back to it today. Repaired the board with new trannies from Ed
(Thanks Ed K!). Then disconnected the coil and checked it again. &^%$#!! me-
0 ohms! WTF- I had tested it before. Pulled the coil out to throw it in the
bin when I noticed a diode on the back of it.... Yeh you guessed it - it was
of course the wrong way round and just shorted out the board. Cut the diode
out and away it went
Gees do I feel dumb
Tony
CARGPB18 ( and it shows!)
"tony holdgate" <tonyho...@hotmail.com> wrote in message
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