Wells Gardner K7000 color problems

Opel

Bashful Neophyte
Joined
Oct 28, 2001
Posts
16
Hi all,

I'm working on a WG 25K719x which I've only got green on. I did a full cap kit on it, plus replaced the HOT and voltage-regulator, and this gave a cleaner image, but I've got no blue or red on the tube at all.

Someone had worked on this monitor before, and were in a hurry or something, as things weren't done quite right, and I'm wondering if any of these shortcomings would have blown out the red and blue ability in the tube itself, or if the chassis boards are the only problem?


The big three of these problems:

The wire to the suction-cup(?) on the tube from the flyback-transformer had its hook(?) broken off at some point, somehow, and had been soldered back on, and this fell off when I pulling the boards again yesterday. Would that weak connection compromise the flyback, or anything else for that matter?

And then the ground-wire to the neck-board didn't have a connector, so it had been cut, stripped, and twisted back together when it had been reinstalled (but not well enough that it had stayed twisted together), but this didn't get caught before the cabinet was powered, so I don't know if that would have blown any components?

And then the big chassis board wasn't screwed down, and was just sitting on its chassis-tray, and I don't know if anything did short out from it this way, but the whole thing did power and work without giving off any smoke/smell, before I got into it and found it in this condition.

I did test the three transistors on the neck-board there (though I did do it with them all on the board still), but they seemed similar enough that if the green one is working, the red and blue transistors are also okay...?

I'm about ready to order a new flyback, IC3 [upc1397c], and the three neck-board transistors, unless what I've said here makes anyone think the tube is shot?
 

MKL

Basara's Blade Keeper
Joined
Mar 8, 2002
Posts
3,685
If the contact in the anode cap is damaged it can be replaced without replacing the whole flyback but I don't think any online shop carries them. I have lots but I'm in Italy. If you see a free PC monitor (not a TV) in your area you can take it from there.

To see if the red and blue cathodes are OK you can isolate the respective pins in the CRT socket and short them to ground through a 1K resistor. If the screen becomes red or blue the tube is OK. If it's not clear post a pic of the neckboard (solder side) and I'll show you what to do.
 

Hine62

Krauser's Shoe Shiner
Joined
Jul 15, 2005
Posts
228
if you are missing colors, check the connection from the pcb to the cassis. I had a red color problem and all it need was to be resoldered at the pcb socket. I also check the plug and found the wires needed to be fixed. You could also switch the green with blue and red and see what happens. If you gain a different color, then you know the circuit works.

If the chassis was loose and removed a lot, check the wires first. After this check get out your multimeter and follow the circuit it seems some connection is being lost.
 
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