K7000 Help. B+ = 165V

[modessitt]

If I am getting a reading of .7 ohms (reads shorted to me) on the red and blue yoke connector, would it be like not plugging anything in?

I have the same symptoms, and just don't want to be chasing the chassis if it's not that.

Would a rotted yoke cause a voltage spike and put the monitor into shutdown?

Some of the yokes will measure that low on the horizontal yoke, especially some of the newer K7xxx series like the 7302. Which specific model is it?

 

[richiewoo]

It's a....

Wells 19K7935

I had this in a different post. I know that the Wells yokes are low impedance, but I posed the question just so that I can find an area to focus on.

You know, like if it's the yoke, fine, I know the chassis is good. I don't have anything else close enough to test it with at the moment, but if I know the yoke doesn't matter too much, I can keep at the chassis.

If it's the chassis, fine too, but I just don't want to keep going over and over the chassis if I know the yoke is causing my problem (which is B+ of 165 and it's in shutdown). I made a separate thread, then started to look for yoke measurements.

If red and blue on the yoke are shorted, could it cause a spike in B+ and put it into shutdown?

Thanks!!!

 

[KevinMullins]

If I am getting a reading of .7 ohms (reads shorted to me) on the red and blue yoke connector

What do you get for yellow and green ?

 

[Ohmerone]

BTW - if you have replaced all the parts (including flyback), R103, R89, and R101 are good, C36 is the proper 612/.0061 capacitor, and you still have a B+ of 160, then you are about 95% likely to have a trace/pad problem somewhere in the section around the horizontal width coil or behind the flyback.

There is a 5% chance that your "measured as good" VR is actually bad, especially if you haven't replaced it yet. I don't see that very often, but I have seen it. It measures as good with the meter, but then doesn't rectify properly under load....

I agree Those Resistor are the key to the Horizontal circuit and the load.and R96
And C36,it can fool you..as it changes value. Not always just shorted.
Most of the time its a bad trace between the resistors that feed's voltage
to the Hor Driver and HOT and Yoke.
The Fixed Regulator is part of my cap kit

 

[modessitt]

Wells 19K7935

I had this in a different post. I know that the Wells yokes are low impedance, but I posed the question just so that I can find an area to focus on.

You know, like if it's the yoke, fine, I know the chassis is good. I don't have anything else close enough to test it with at the moment, but if I know the yoke doesn't matter too much, I can keep at the chassis.

If it's the chassis, fine too, but I just don't want to keep going over and over the chassis if I know the yoke is causing my problem (which is B+ of 165 and it's in shutdown). I made a separate thread, then started to look for yoke measurements.

If red and blue on the yoke are shorted, could it cause a spike in B+ and put it into shutdown?

Thanks!!!

Your main problem is you don't know what the problem is.

Normally when a yoke is bad, you'll get two results:

1) Open yoke - no deflection at all on that axis. If your horizontal was open but your vertical wasn't, you'd have a vertical line (horizontal mounted) on the tube.

2) Shorted yoke - usually will cause other parts on your chassis to burn up due to the increased voltage draw.

I'm betting on the fact that your issue is with the chassis. I have people tell me all the time that they have gone over the entire chassis looking for bad solder or broken traces and not finding anything, and then I find it within 30 seconds of getting it. It's not always obvious or constant. Sometimes a trace will be connected, but then disconnect under heat or a flexing of the board.

K7000 yokes are not hard to get ahold of (is your's med-res?), so if you REALLY want to be sure it's not the yoke, get another yoke....

 

[richiewoo]

Ok, I can live with that!

I'll keep going over it then. I'm not discounting that I didn't miss something, it was just that, everything seemed ok, except for a shorted yellow and green on the yoke.

I am trying to get a hold of a similar yoke to test with, and will continue to go over the board.

I appreciate the responses and will continue to plug away.

I think I was getting 8+ or so ohms from red and blue on the yoke.

Again, thanks!

 

[PrairieDillo]

I've read this thread like 2-3 times trying to learn everything I can from it.

Thanks guys... it helps me on my own trouble shooting of my K7000 19"
I didn't know i could take out the chassis and test it for power out of the monitor.
Thats a big help in trying to figure out my power issues. I was thinking... how do these guys the test power section when it's under the yoke????