Gottlieb Joker Poker KING target bank locked on

[Todd Tuckey]

This has me completely baffled...have a new power supply, a new ni-wumphf
logic and good driver board---even swapped them out for other boards. Also
installed brand new intercommect cable between logic and driver board.
Changed the transistor thats on the coil underneath the playfield too. For
no reason, when you turn the game on every now and then, the Kings coil
locks on....turn it off and on 3-5 more times, and its fine.
I did a google search and found the same kings coil gave people problems
years ago, but with no real satisfactory success.
Well folks, any suggestions???? Todd from TNT Amusements Inc

[Mark Clayton]

Todd:

Did you add the pull-up resistor on the base of the transistor?

-Mark
--
http://pinballpal.com/

This has me completely baffled...have a new power supply, a new ni-wumphf logic and good driver board---even swapped them out for
other boards. Also installed brand new intercommect cable between logic and driver board.
Changed the transistor thats on the coil underneath the playfield too. For no reason, when you turn the game on every now and
then, the Kings coil locks on....turn it off and on 3-5 more times, and its fine.
I did a google search and found the same kings coil gave people problems years ago, but with no real satisfactory success.
Well folks, any suggestions???? Todd from TNT Amusements Inc

[s***@farrar.com]

Mark,
Is adding the pull-up resistor a "mod"? Documented somewhere?

Is this to be done to the Transistor under the PF or on the Driver
Board? Which one?

Thanks

[Mark Clayton]

Scott (and Todd?)

Yes, it's been documented in a number of places. It was in a Gottlieb advisory, the PinLiz
guide, and it's in Clay's System 80 guide here:
http://marvin3m.com/sys80/index1.htm#pullup

-Mark

[Gott Lieb?]

Scott,

Clay covers the mod in the Sys80 section.
http://www.marvin3m.com/sys80/index1.htm#pullup

Jim

[s***@farrar.com]

Let me know what you find out as this is EXACTLY my situation!

I have a rebuilt Power Supply and NiWumpf board in mine. I have tried
a Rottendog Power Supply and the game still has those problems.

The part that bothers me (other than knowing this isn't right) is I
know the "sound" the Kings DT makes when it pulls in when I turn the
game on so I can quickly turn the game off, HOWEVER, I don't trust my
kids (being they are kids) to turn the game on when I'm not there as it
will burn up the transistor on the Driver Board (hint, hint - it was
burnt up when I bought the game). Also, I will feel bad passing this
liability onto a future owner someday.

Later

[Todd Tuckey]

Wow...never knew about this mod...is there anything written about it? There
seems to be nothing in the manual....I appreciate it Mark! Todd

[Todd Tuckey]

thanks...will try this tomorrow and see if it fixes it! Todd

[Todd Tuckey]

Added the resistor that Mark pointed me to, and Kings have not locked on
since...Its just odd as I have had some 15 Joker Pokers go through here over
the years that may/may not have had that resistor added. I will be watchful
and check others that may need that resistor mod (I am thinking Countdown
for instance). I never noticed it on Marvin's site as it applies to the
System 80's! Thanks again folks!! Todd

[Steve Kulpa]

Hmmm, I don't have a pull-up resistor on my JP and have no problems
either.
I thought that mod was just for the system-80 under-playfield
transistors.

steve
---
Steve Kulpa (cargpb10)
Hermitage, TN
http://www.geocities.com/stevekulpa/pinball.htm

[Mark Clayton]

Todd:

Hope that fixes it for good. I didn't notice if the Gottleb fix that's
on Marvin's site was just for System 80, but the principle is the
same. They cheaped out and left the base to the transistor
unbiased so under certain conditions it can latch up like an SCR.
It doesn't happen all the time because you need the right combination
of transistor gain, capacitance, and who knows what, with the right
trigger at power on, maybe a positive or negative spike of sufficient
voltage, or a period of high impedance when (maybe) the solenoid
voltage is present but the +5V logic supply comes up a few milliseconds
later.

Nice to help you out too, Todd - I remember visiting your place one
day and we were walking through your showroom. One of your techs
was struggling with a Gottlieb System 3 (Class of 1812, maybe), and
with barely a pause, you told him that a certain group of chips on the
CPU board were succeptible to failure, and when the fail, they run hot.
You ran your finger over the board, and in about 1 second ID'ed the
bad chip. I was very impressed...

-Mark

[Todd Tuckey]

never had a scope and rarely use a meter...I like to eyeball the board
first---look for slight cracks in chips, etc...fixed many a board in my
day...just started selling system 1 Gottliebs again because the power
supply, logic and interconnect cables can be purchased new--to make the damn
games dependable again! This drop target bank had me puzzled as it was so
intermittent---Guy who got the game is so happy (we also decked it out with
new plastics and targets from Pinball Resource) that he ordered today a Mata
Hari. Todd

[s***@farrar.com]

Todd,
Where did you find the 24VDC on your Joker Poker?

I need to do this mod but I can only find 25VDC at my Fuse Block (and
in the schematics). Is it OK to use 25VDC instead of 24VDC?

Thanks

[John Robertson]

Post by s***@farrar.com
Todd,
Where did you find the 24VDC on your Joker Poker?
I need to do this mod but I can only find 25VDC at my Fuse Block (and
in the schematics). Is it OK to use 25VDC instead of 24VDC?
Thanks

The solenoid voltage should be stated as 'roughly' 24VDC. Anything from
around 20VDC to 30VDC is fine.

Check your ground connections and move the battery off the MPU board!!

John :-#)#