wells k7000 problem

mrbill2084

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I was repairing the wells k7000 in my dedicated trog. It was DOA when I got it. I recapped, replaced the hot and reg. I cleaned up and reflowed some burt looking connections. 1 was at r103.

I stuck it back in and I could hear arcing (sounded like in the tube, but it could have been from the fluyback). Before I shut it down I could see r103 glowing red (large sandbox resistor).

I pulled the chassis out and the fuse was not blown. So I put the chassis on another tube and it looked pretty dead(no arcing). I was going to put another rebuilt wells chassis into the trog, but I thought I would ask a question first.

My question is, if the tube is shorted, could it damage the new chassis? I am going to borrow a rejuvinator this weekend. Can detect shorts and or clear them out?
 
And you remembered to replace the mica insulators between the chassis and regulator & horizontal output transistor? And of course you applied fresh silicone heat sink grease to both the regulator & horizontal output transistor AND the mica insulators?

Why didn't you replace the flyback? Originals fail all the time. They blow out the side and arc to the frame.

Also critical safety capacitor C36 goes bad.
 
Was it arcing at the anode cup or the neck / socket of the tube? If socket then likely tube issue / leak... if anode cup your hv could be running to high from a flyback timing pulse malfunction or a bum tube... the inherent capacitance or dielectric properties could have changed on the tube also.

Ken is right, if the fly is original in a k7000 change it.. they are just as bad as any original g07 flybacks now.. They are craping out left & right. I now automatically change out any original flyback in a k7000 with a new without question.
 
I was repairing the wells k7000 in my dedicated trog. It was DOA when I got it. I recapped, replaced the hot and reg. I cleaned up and reflowed some burt looking connections. 1 was at r103.

I stuck it back in and I could hear arcing (sounded like in the tube, but it could have been from the fluyback). Before I shut it down I could see r103 glowing red (large sandbox resistor).

I pulled the chassis out and the fuse was not blown. So I put the chassis on another tube and it looked pretty dead(no arcing). I was going to put another rebuilt wells chassis into the trog, but I thought I would ask a question first.

My question is, if the tube is shorted, could it damage the new chassis? I am going to borrow a rejuvinator this weekend. Can detect shorts and or clear them out?

Dumb question. Do you have the GND from the tube connected to the neck board? If you dont the chassis will arc to the frame at that screw hole in front of the flyback.

Matt
 
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