Wells Gardner K4600 with blue smear

[Keith Jewell]

I have a Wells Gardner K4600 in a cocktail style game. When I got it,
there was no blue, and it had very poor geometry. I did a cap kit,
which cleared the geometry up as well as made for an overall clearer
and much more stable picture. Also, replaced TR403 on the neck PCB,
which was shorted, with the NTE cross. The picture is overall pretty
good now but the risetime seems to be bad on the blue. In other words,
the blue has smeared edges on both the rising and falling. Switching
colors on the input changes nothing, so I'm sure it's in the monitor. I
figure this is one of the following, but can't be sure. Any ideas? I'm
thinking:

-One of the other two transistors (TR204 or TR207) is marginal but
still tests good
-A small cap that wasn't in the circuit is bad
-The NTE cross isn't a good cross in some way

It just occured to me writing this message that I can try switching
around the colors going to the neck board to further isolate the
problem, but has anyone seen a problem like this before? It's not so
bad, really quite usable now, but I'd love the blue to be as crisp and
clean as the red and green are. Thanks.

-Keith

 

[Steve Muccione]

switch the colors first...

if it moves you can swap transistors to verify the cross was ok (yeah it's a
bitch to resolder but...)

 

[Robert Bullock]

Try adjusting the color drives and cutoffs. Also contrast and screen knob on
the flyback. If you can't get it low enough and still get red and green,
might be time for a rejuve or clean and balance on the tube.


In other words,

 

[Keith Jewell]

See, I was wondering that - but contrast isn't a problem. In fact, I
have to set insane settings on the drives and cutoffs to get a blue
background raster, and apart from some mild burn, the tube is bright
and sharp with generally good convergence. I'm really thinking
electronics here. I suppose I won't know until I switch the colors,
really should have thought of that first.

-Keith

 

[Robert Bullock]

Well if you're getting blue backgrounds then the blue drive transistor must
be working, I'd try a clean and balance and then a rejuve if that doesn't
work.