K4600 Issues

FrizzleFried

Well-known member

Donor 2011
Joined
Mar 20, 2007
Messages
54,193
Reaction score
5,245
Location
NAMPA, Idaho
Alright, so I get the Wizard of Wor to actually show an image on screen and guess what... the monitor is acting up...

Evidently only the blue gun is firing as the entire screen is blue... background, characters, everything. What is also strange is that it appears as if the screen is set too high, but the screen knob on the neckboard (strange place for it) does absolutely nothing. Also, the pot that is on the input expansion card appears to adjust the screen, but either the image shows way too much screen (blue hue over everything and you can see the scan lines) or if you turn it down from there the entire image fades away to nothing.

There is no true black showing either...the black has a blue tint.

SO... am I looking at a re-cap or something more? I have a feeling the tube is shot, but what do I know. This, of course, sucks, being that the only other monitor I have is the K4900 which has a shake to it (been recapped) and doesn't quite "focus" completely.

BTW: I tested the game PCB with that 2nd monitor and reds show up, so it's not the gameboard....
 
Start with a recap of the 4600, and if you have to replace the color transistors.

The 4900 that has the shakes and will not focus has a bad fly, and you will just have to wait until new flys become available.
 
OK...the black level adjustment appears to be working...it's the screen adjustment on the neckboard that does nothing... is that something a cap kit can rectify?

I have to order a kit... and I'd rather not bother if this is a lost cause and come up with another solution...but if a cap kit can rectify a non-working screen adjustment and/or red circuit, I'm all over it.
 
I'm ASKING...

Screen pot does nothing....

Black level pot works but goes from VERY bright to dark instantly and fluctuates at the touch...

Also... am I THINK the blacklevel is dimming out because there's only blue on the screen...no other colors or brightness so it (the blacklevel) sort of overtakes it?

I guess I should start with a cap kit and then go from there. I also happen to have a G07 chassis on hand and a compatible tube, but the G07 blows the small fuse....which indicates a flyback/hot issue ...and I've yet to be successful at replacing a flyback (I am 0 for 1 ...though it was a medium res k7000 that I failed at).
 
I'm ASKING...

Screen pot does nothing....

Black level pot works but goes from VERY bright to dark instantly and fluctuates at the touch...

Resistor R419 (330k, half watt) on the neckboard located directly behind the screen pot is open. You'll need to unsolder and lift one of the resistor's leads to check it.

And while you're at it, install a capkit in this monitor. Be sure the capkit includes a new black level pot (Zanen Electronics' kit does) because they are a high failure item.
 
Can someone explain exactly how to determine what size a resister is? What "color" bands should I look for for a 330K .5 watt resister?
 
Can someone explain exactly how to determine what size a resister is? What "color" bands should I look for for a 330K .5 watt resister?

http://en.wikipedia.org/wiki/Electronic_color_code#Resistor.2C_capacitor_and_inductor

There are several "colourful" mnemonics listed on that page to help you memorize the resistor codes. The one I learned in school is not one of the politically correct ones. :eek:

The colour bands don't indicate how many watts it can dissipate, but you can generally judge by the resistor's size.
 
When a color gun is stuck on or shorting on and off.....it could be the actual tube....or it could be something in the color circuit of the chassis. The easy was to isolate the problem....remove the color driver transistor. In your case (WG4600...color-blue), remove transistor X406 from the neckboard. This will eliminate the possibility of any "blue" signal reaching the tube. Fire the monitor up. If the color blue is still sticking on....it's your tube. If your image is now devoid of all blue....the issue is in the blue color circuit of the chassis.

Edward
 
Non thus far. Waiting for a Bob Roberts kit... and I have multiple other projects to keep me busy (Damn Wizard of Wor issues... Battlezone issues...).
 
Back
Top Bottom