Hi all,

One of those vivid blue & white monstrosity with odd 3 legged stand
came in for estimate. No picture, power LED lit and reacting to video
input. Can hear relay click with resolution change. No static on the
CRT.


Checked everything even found the jungle IC off the 'net to see I'm
getting horizontal pulses for the flyback transistor, it does.
Vertical working, horizontal also working except I'm not getting any
HV. Yes you heard that, no HV.

Seen this happen with no HV problem yet monitor works? No fizzing or
fssssss! noise. Not even a blown HOT or smoking flyback.

Cheers,

Wizard

"Jason D." wrote in message
...
Hi all,

One of those vivid blue & white monstrosity with odd 3 legged stand
came in for estimate. No picture, power LED lit and reacting to video
input. Can hear relay click with resolution change. No static on the
CRT.


Checked everything even found the jungle IC off the 'net to see I'm
getting horizontal pulses for the flyback transistor, it does.
Vertical working, horizontal also working except I'm not getting any
HV. Yes you heard that, no HV.

Seen this happen with no HV problem yet monitor works? No fizzing or
fssssss! noise. Not even a blown HOT or smoking flyback.

Cheers,

Wizard

While not on that particular monitor I have seen the no HV thing with
working horizontal. Check the B+ at the flyback, as long as you have
something there you should get something in the way of HV out even if it's
low. The flyback is probably driven by an N channel MOSFET, shouldn't be too
hard to see if that's working.

Checked everything even found the jungle IC off the 'net to see I'm
getting horizontal pulses for the flyback transistor, it does.
Vertical working, horizontal also working except I'm not getting any
HV. Yes you heard that, no HV.

Seen this happen with no HV problem yet monitor works? No fizzing or
fssssss! noise. Not even a blown HOT or smoking flyback.

Cheers,

Wizard

While not on that particular monitor I have seen the no HV thing with
working horizontal. Check the B+ at the flyback, as long as you have
something there you should get something in the way of HV out even if it's
low. The flyback is probably driven by an N channel MOSFET, shouldn't be too
hard to see if that's working.


How I have forgotten to say that, yes did have B+ there and I can see
thin pulses to the flyback, did check for open primary winding and was
not.

Cheers,

Wizard

While not on that particular monitor I have seen the no HV thing with
working horizontal. Check the B+ at the flyback, as long as you have
something there you should get something in the way of HV out even if
it's
low. The flyback is probably driven by an N channel MOSFET, shouldn't be
too
hard to see if that's working.


How I have forgotten to say that, yes did have B+ there and I can see
thin pulses to the flyback, did check for open primary winding and was
not.

Cheers,

Wizard

Hmm well you've got pulses at the primary of the flyback, have you measured
the HV at the tube? Is the B+ level reasonable? Are the pulses of sufficient
amplitude or is it just noise? Do you have heater glow in the neck? It's
possible that you do have HV but something else is missing, or that the HV
is too low. Could be other power supply voltages derived from the flyback, a
short in one of these could drag the HV down.