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Old 11th May 2010, 9:29 am   #22
PJL
Dekatron
 
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
Default Re: Oh no - another V4!

Quote:
Originally Posted by dominicbeesley View Post
This just doesn't seem right to me why is K going down when brightness goes down!?!

Then I knocked the ion trap again and got a raster of sorts - this time with brightness at minimum! fiddling about with ion trap and focus I got blurry but distinct lines then it went again when fiddling with ion-trap.

Then I noticed the CRT base is loose!

My conclusion: broken K wire in CRT base which is occassionally making contact...but what to do? Is it as simple as solder sucking the pins and sliding off or will that knacker the job?

Any advice gratefully accepted if no better ideas while I have my dinner out comes that sucker!

Dom
Having spent far too much time looking at the 'other' thread, here are some answers.
- A1 reads low due to 10M feed resistor so x2 when using DMM
- Is it grid current keepiing the voltages the same? G1 should be < K
- Plenty of measurements in the other thread. Boost should be >450V
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