Midway Terminator 2 Gun Problem

[Ken B.]

I'm a group "Newbie" with a Terminator 2 gun problem. The guns will
fire but won't aim. All 4 pots (X&Y axis) ohm out as good but the x
and y values don't change when I go through the gun calibration
procedure. I repaired broken wiring (at the pot terminals) checked
guns still won't register position values (stays at x1=255, y1=0,
x2=255, y2=0). There is a cmos analog to digital converter in the
chain (ADC0844CCN). I'm wondering if this could have been fried when
the wires broke. Help! The Terminators are coming! Any help will be
appreciated!

[Clay Cowgill]

"Ken B." <kenba...@hotmail.com> wrote in message
news:81b261fc.03022...@posting.google.com...

> There is a cmos analog to digital converter in the
> chain (ADC0844CCN). I'm wondering if this could have been fried when
> the wires broke. Help! The Terminators are coming! Any help will be
> appreciated!

If the pots look good out of circuit, check that you get a voltage range
output from them in circuit (just incase it lost a ground or the +5 to the
pots or something). If you get a varying voltage with the guns plugged in,
I'd start with the ADC0844 as well. (I think National obsoleted those a few
years ago though so it might be hard to find a replacement... I could be
wrong, been a long time since I looked at one of those.)

-Clay

[Art Mallet - Artfromny - formerly A218@aol.com]

I have seen 3 or 4 of these games, and they all had the adco844 socketed -
it had been replaced. very likely place to look
"Clay Cowgill" <cow...@attbi.com> wrote in message
news:EXU7a.270981$SD6.13490@sccrnsc03...

[Ken B.]

Thanks everyone. The A/D converter does sound like a likely place to
start. I ordered a couple of the IC's from WZMicro's today and with a
little luck from the postal service I'll have the guns firing this
week.
Many thanks again...ken b.

"Art Mallet - Artfromny - formerly A2...@aol.com" <artg...@nycap.rr.com> wrote in message news:<1N18a.49482$%r1....@twister.nyroc.rr.com>...

[Ken B.]

kenba...@hotmail.com (Ken B.) wrote in message news:<81b261fc.03022...@posting.google.com>...

Fixed the gun problem on the T2 (Thanks to all for your help)! I did
install a socket and replaced the ADC0844CCN analog to digital
converter chip. Guns now calibrate and work fine. WZMICRO.COM had the
chips for $5 each. I've still got a problem with the monitor after I
installed the cap kit that I got from Zanen Electronics. The top of
the picture "warps" vertically over the top of the monitor. I can
bring it back by adjusting the vertical hold pot but of course it
won't stay there (out of vertical sync). Anyone know of a good place
for monitor chassis repair/swap out for a 25K7197 Wells-Garnder
monitor chassis or have any idea where I might look next in the
circuit to fix the problem?

[Art Mallet - Artfromny - formerly A218@aol.com]

The 0844 is a very common problem with these

Art

"Ken B." <kenba...@hotmail.com> wrote in message
news:81b261fc.03022...@posting.google.com...

[valfl...@gmail.com]

I just got my hands on a T2 unit. We are very new to the repair world. The right gun only shoots to the left. I don't even know where to begin to fix it.

[John Robertson]

On 2019/02/09 6:12 p.m., valfl...@gmail.com wrote:
> I just got my hands on a T2 unit. We are very new to the repair world. The right gun only shoots to the left. I don't even know where to begin to fix it.
>

Begin by getting the owners manual for the game and read the
troubleshooting guide.

Often problems with gun games, if out of adjustment, can be traced to
the monitor picture tube fading or bad caps - which may need replacing.

John :-#)#

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