Tech: T2 help. Backbox GI strings not working properly.

[Rock]

I just got this one home last night. Quite the project, but things
have been coming along great so far to my surprise. Been working on it
for about 14 hours now and I am almost done. This is my last problem.

Basically this seems to be a J120 issue. The flashers work fine, no
issues. When I got it home only the top string was on and functioning
properly. I opened up the backbox to take a look and everything
"looks" alright connected to the J120 pins. Whoever worked on the
machine before swapped out the IDC connector for trifurcon. It's the
only one of the connectors that had been swapped out.

So here is where it gets weird. While adjusting the connections on the
J120 with no results, I accidentally touched metal to metal with 2 of
the wires, it made the bottom string GI come on and the top string go
out. Strange stuff.

Instead of messing around anymore, (to the dismay of some here) I
swapped out the trifurcon pins for a brand new IDC connector and did
my research to make sure the wires were all in their proper places.
Now when I plug the connector back in, none of the GI backbox lights
work at all, and now here is where it get weird again. This was
another accident, but it showed me that all of the backbox GI lights
are in fact working, just not when connected the way it's supposed to
be. When I move the connector one spot to the left (improper spot),
each time I can get the top GI to turn on, then move it to the next
left spot, CPU GI string comes on, then one more spot to the left and
the bottom GI string comes on.

Any ideas on what the heck is going on here? Maybe I need to replace
the pins? Thanks.

[c...@provide.net]

Don't use IDC connectors for this game!
T2 is NOTORIOUS for burning backbox GI
connectors. Frankly there's too many 555
lamps to handle the heat and current. Using
an IDC makes things worse.

Personally i take out about 20% of the GI backbox
bulbs in T2 which really minimizes connector burn.
Also set Adjustments Standard to power level
"4" and after "2 minutes". This helps dramatically
too.

If you don't have the proper IDC tool,
there's just no way you should be messing
with IDC connectors.
Crimp trifurcons are the only way to go.
Yes you need a special too for that too.
but that tool luckily is only $12, and you
will use it a lot for other stuff.

Each GI string is a pair - power and return.
Connectors J120 and J121 are parallel too.
so you can swap connectors between them
if you suspect a problem.

Back to the pair. Green and White/Green.
Yellow and White/Yellow. Those are the pairs.
But you can cross the White/Green with
the solid Yellow and the GI for that string
will work. You can do this to figure out if
there's burned traces on the connectors
(very common.)

[Borygard]

I've seen similar issues way too often. I'd say you've got a couple of
different things going on. You've got a driver board issue with at least
one bad GI string. Could be traces, Triac, etc. When a previous owner
tried to correct the problem, instead of actually fixing the issue on the
driver board they re-wired J120 and J121 to get some of the strings working.

So, check wiring at both J120 and J121 to make sure they're correct, once
that's confirmed check the voltage into and out of the strings that are not
working.

--
Rob Anthony
Pinball Classics
www.LockWhenLit.com
Quality Board Repair - In Home Service
314-766-4587

"Rock" <bizm...@gmail.com> wrote in message
news:6bdd28e0-072f-4dff...@g23g2000vbr.googlegroups.com...

[Lloyd Olson]

If connectors were ever replaced, the pins should have been done too. And
then with a meter, check continuity of each pin onto the board somewhere, to
be sure you have through and across board continuity. LTG :)

"Rock" <bizm...@gmail.com> wrote in message
news:6bdd28e0-072f-4dff...@g23g2000vbr.googlegroups.com...

[Rock]

Hey Clay, thanks for the info. I gotta tell ya, I am sooo freakin glad
that you came out and helped me out with ToM a few months ago. You
showed me like 4 or 5 things and now I have been tackling a ton of
problems on my own. It feels great and I owe a lot to you for all of
your help, along with good ole Lloyd, The Korn and a lot of other nice
members on RGP. I would have been lost if you never came out that day.
I'm going to post some before and after pics of this T2 and I think
you'll be proud that I was sort of a student of yours for the half
hour you were here haha. I've got a lot of parts coming in, but wow
it's coming along great. I've done so much work to in in about 14
hours. It feels great, feels like the machine is happy someone is
actually taking care of it. It plays great now.

I will definitely take all of your advice on this issue and run with
it. Thanks so much. It's time I learn how to use trifurcon pins from
now on. Just a quick question about them, one of the connectors looked
pretty bad, do they just go bad sometimes? Maybe this whole problem
started with one of the connectors the previous owners had on the J120
crapping out.

[Rock]

Thanks for chiming in everyone. I will take all of your advice and see
what I can do. I'll update this if I can get something worked out.
Gonna order some trifurcon connectors/tools and replace the connector
pins this week. I also need to swap the battery holder because the
previous owners didn't know you had to change them. Luckily only the
battery holder was ruined from corrosion and nothing on the board.

[c...@provide.net]

I think any tool (crimp or an IDC squeezer) requires
some practice to use correctly. I did a web page on
crimping. check it out:
http://marvin3m.com/connect

Often people don't really know how to crimp,
so they make a mess of things. Again practice
and patience is the key.

One thing to remember. williams usually
didn't "double up" a GI string. That is, there's
five GI strings in a T2. Usually they use three
for the playfield, and two for the backbox
(sometimes it's the other way around, depends
on the game.) For T2 they use two GI strings
for the lower and upper lights, and a separate
string for the "computer" string in the middle
of the playfield.

So if you look at J120 and J121 as a single
connector (really they are, as they are "parallel",
no two lines should be "doubled up." That is,
the green and white/green shoud be on say
pin 1 and pin 7 for the backbox on connector
J121. Now look at the playfield J120 connector,
and pin 1 and pin 7 should be empty.

Likewise say for the playfield they use
purple and white/purple on connector J121
at pin 3 and pin 9. Now if you look at the
J120 backbox connector, these pins should
be empty!

The reason for this is simple - there's only
so much current that can be handled by
any connector. There are some exceptions
to the rule (for example on T2 that "computer
string" in the center of the playfield MAYBE
is shared by a GI backbox string.) But for
the most part, a string handles either the
backbox or the playfield, and not both.

[John Wart, jr]

On a production T2, J120 (backbox insert) has the brown and orange strings
only.

Playfield has green, violet and yellow.

<c...@provide.net> wrote in message
news:2c49a5f5-7d30-463a...@p28g2000vbi.googlegroups.com...

[Rock]

Great info. I really appreciate it.

"On a production T2, J120 (backbox insert) has the brown and orange
strings
only."

So this is accurate then correct?

Pin 1- Brown
Pin 2 - Orange
Pin 3 - Yellow
Pin 4 - Key
Pin 5 - Green
Pin 6 - Violet
Pin 7 - White-Brown
Pin 8 - White -Orange
Pin 9 - White-Yellow
Pin 10 - White-Green
Pin 11 - White-Violet

[John Wart, jr]

Correct, but not all connectors use all wire colors, as Clay said, some
supply the PF, some supply the backbox insert, sometimes a string is shared
between both the PF and backbox insert etc.

"Rock" <bizm...@gmail.com> wrote in message

news:6446d0ca-ae56-433c...@f10g2000vbl.googlegroups.com...

[Rock]

When I looked on the board for the first time, there were only 4 wires
connected, brown, orange, white-orange and white-brown. Is this what
should be connected to the J120?

[Damian Parrino]

yes, that connector should only have 4 wires (brown / orange) going to
the backbox.

regards
Damian

[c...@provide.net]

Right, that's TWO pairs of GI.
Because the playfield uses
THREE pairs. This makes a
total of FIVE pairs, which is
the max a WPC game can
use.

as you posted, and modified:
Pin 1- Brown - backbox pair 1a
Pin 2 - Orange -backbox pair 2a
Pin 3 - Yellow - PF pair 3a
Pin 4 - Key
Pin 5 - Green - PF pair 4a
Pin 6 - Violet - PF pair 5a
Pin 7 - White/Brown - backbox pair 1b
Pin 8 - White/Orange - backbox pair 2b
Pin 9 - White/Yellow - PF pair 3b
Pin 10 - White/Green - PF pair 4b
Pin 11 - White/Violet - PF pair 5b

[flip...@hotmail.com]

OK, I know this is a weak point on most games but if you replace the
male and female connections, use the correct tool to crimp the wires
as original shouldn't that work just fine for the average collector?
After all we won't have our games on for 12 plus hours a day every day
like on location. My point is that by the time this becomes a problem
again my grandkids will have to fix it! IMHO. Your thoughts?

Kitch

[erickit]

> (very common.)- Hide quoted text -
>
> - Show quoted text -

I had a burnt connector and pins on a board and I had never done this
repair before so I practiced on an old board till I felt confident I
could get the old pins out without lifting any traces. I soldered in
the new pins and added a jumper to the one with the burned trace. I
then replaced the female connector, put the board back in and hooked
it up. Nothing. :(
I buzzed the female connector to the backbox made sure I got all the
wires in the correct spots and everything was fine there so I figured
I screwed up on the board so I pulled the board again and rechecked my
work, everything there buzzed out fine. Time for some head scratching
then I decided to plug a new male set of pins into the female and buzz
the backbox again and found the problem, one of my newbie crimps was
munged and wasn't connecting to the pin.
I popped it out cut off the bad crimp and redid that crimp, hooked it
all up and everything worked.
Now I test all connectors I replace by plugging in a male and testing
from the pins instead of the connector.
I would have saved a lot of time if I would have done this in the
first place.

Eric

[Rock]

Soldered on new pins on J120 and POOF they work! =) This machine is
running at 100% now. I put tons of LEDs in the right spots and it
really pops now. Awesome. Thanks for the advice peeps!