K4600 Issues

[SirPeale]

Have a K4600 that WAS working perfectly.  Right until somehow, someway, the neckboard got split in two.     INSIDE a damn cab.

Tube is okay, so I attempted to put it back together.  Everything /looks/ okay, I have continuity on all traces.

I've got high voltage, at least I'm pretty sure I do because the screen gets charged with static.  No neck glow.  I've checked and double checked the connections on the neckboard, all appear to be sound.   R422 reads @ 1 Ohm.

I'd read the heater voltage except I've read that you need a true RMS meter to get an accurate reading, and of course I don't have one.

Any ideas?  I'm clueless here.

[qrz]

depending on the crt size/type , filament pins are 4,5 or 9,10
with "neck board" diconnected , u should read a low res across these pins on the crt .
with same condition above , u should also read a low res across the same pins on the skt.
if not , there is a break in the fil winding.   note : usually one side of the winding is ground

qrz

[Kevin Mullins]

It ain't missing the ground somewhere is it ?
(on the neckboard itself)

[qrz]

usually , there is a single ground pin on the fly.
several windings are then referenced to that pin.

removing the socket breaks the loop . so, u should read low res from either fil pin to gnd  ....


qrz

[SirPeale]

QRZ: define "res".

[qrz]

sorry, been at this so long i tend to forget others are not so familiar with the technobabble. 
just another hazzard of being an " old fart "

low resistance.   in this instance < 1 ohm


qrz

[SirPeale]

I get the technobabble, but sometimes I have trouble with your abbreviations. 

I'll check it out.

[SirPeale]

Finally got around to figuring this out today.

When I said I had continuity on all traces, what I meant was all traces that were torn in two by the neckboard cracking.

There was one that I missed.  You guessed it - one of the heater traces.  I thought it looked iffy before, so I checked it and sure enough...zero ohms.

Hit it with a soldering iron, and it was sliding all around.  Just a solder pad not attached to the trace!  Hit it with my fibreglass pencil to bare copper and now it's working fine.  Needs recapping, but working again.

[SirPeale]

One recapping later and it's awesome.  Didn't have all the caps to replace, but I got 95% with what I had on hand.  Has improved things 100%.  Amazing picture, considering the sheer amount of Pac-Man and Shinobi burn.  The tube is brown from it, yet gives a great picture.