Wells Gardner 19K7302 with red tint

[smalltownguy]

Purchased a 19K7302 chassis from someone over on KLOV a few weeks ago. The neck board was cracked in half, so I obtained a replacement from Carl Blessing at Allgood. After hooking everything up, this is what I get:






I have a feeling there could be an issue with a solder connection on the neck board, or a transistor causing issues. Obviously an issue with red drive. Adjusting the pots will change all the colors incrementally, but nothing removes the tint. Adjusting the flyback moves the image from pure white to pink to red to deep red to black, so I believe the fly's OK. Focus adjustments works just fine.  I don't believe it's the tube, as I've used this same tube with a few other chassis in the same family and have not seen this red tint.

My first thought was to remove the transistor for the red drive and either swap it with another color or pull a transistor from the cracked neck board. Thoughts?

[lilshawn]

My first thought was to remove the transistor for the red drive and either swap it with another color or pull a transistor from the cracked neck board. Thoughts?

exactly.

if it moves colors, bad transistor.
if it doesn't possible bad tube. but check your signal wire from your game for shorts.

[smalltownguy]

My first thought was to remove the transistor for the red drive and either swap it with another color or pull a transistor from the cracked neck board. Thoughts?

exactly.

if it moves colors, bad transistor.
if it doesn't possible bad tube. but check your signal wire from your game for shorts.

Tried same chassis and new neckboard, tube looks great. So it's something on the neckboard. I've swapped transistors, no change. Replaced both red pots. No change. Changed capacitor (100uf 16v) on the neck board. No change.

Next?

[lilshawn]

i'd say video amp.

lm1203 or something of the sorts. could be your issue. there is an NTC replacement for the chip.

or maybe (not sure without a schematic), a sub transistor. sometimes the amp can't power the transistors directly so they run some smaller ones with the amp that run the larger ones for the drive.

but likely the video amp chip.