K7000 B+ at 165+ - My own thread this time!

richiewoo

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**Apology in advance to Dokert! This is a long post!

OK, so I piggybacked onto someone else's thread with this originally, and it's time to start my own thread.

Have a K7000 (19K7935). When I got it, it was arcing like crazy. I replaced the flyback and had a B+ of just over 165V. I started checking and replacing. Did all the stuff below. At this point, after reading a post from someone else, I started suspecting the yoke, so I Ohmed it.

First, the B+ voltages I'm getting:

From the neckboard: 168V
From the large resistor on the side of the chassis (I forget the number at the moment):
Blue side: 165V
Red side: 175V

So I decided to test the yoke.

Between the yellow and green - 8.1 Ohms
Between the red and blue - .7 Ohms (shorted)

Can anyone verify the yoke measurements if they have time? I'm thinking that it's toast. If so, that's both good and bad. Good because I know the chassis is good, but bad because, well, that would mean a shit yoke.

Also, just for informational purposes:

I got it and it was arcing all over the place

Had the white knob flyback - replaced it.

Powered on and got shutdown. Initial HV "crackle" then nothing.

Fuse good.

Replaced c36

Went over most solder

Did the cap kit

touched up more solder to ensure there was no bridging

replaced VR and HOT tonight too.
 
you didnt happen to bump the yoke, drip solder down into it, or drop a cap lead down into the windings did you? that reading does seem low.

HEll i really need to add good known yoke winding readings to the sticky..
 
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sounds to me like the power supply regulator - isn't regulating? If the B+ is too high you can get all sorts of arcing and odd problems as well as causing additional damage to other parts (vertical etc).

Start at the begining - measure and correct the B+ as nothing else can work properly if it is too high or too low.
 
The input voltage to the regulator is too high. (red - 175v)
Backtrack from there.

Do the new VR and HOT have good insulators on them ?
 
you can tell if your regulator works
by hooking a 60-75 watt ac bulb to the R301
resistor blue side wire and the other wire to ground the large heatsink.
odds are you have no load on it thats why its high.
But the bulb trick will bring it down to correct voltage
then you will know if the regulator circuit is good!!
 
Haven't touced it...

Thanks for the suggestions, but I've been on "break" for the Thanksgiving weekend!

In the meantime, is there anyone who can give me a Yoke measurement for a 19K7935?

I need to be sure it's not that before I go chasing more and more.

Thanks.
 
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