From: email@example.com (N. Thornton)
Subject: Re: High Voltage Power Source from Monitor Third Attempt
Date: 20 Nov 2002 17:35:26 -0800
NNTP-Posting-Date: 21 Nov 2002 01:35:26 GMT
Thorfirstname.lastname@example.org (P!erCer) wrote in message news:...
> Well, My device didn't short this time. Oh no. And the actual
> resistance of my resistor array was within 2000 ohms of my
> calculations, and 4000 ohms higher than what was suggested on the net.
> (Wheee Ohms law works for me!) Did the resistor array short? No.
> The device made a buzzing sound, and LIFTED OFF THE GROUND ON ONE
> SIDE. It was really cool. Then, the buzzing...slowed. The frequency
> of the clicks making up the buzz became lower, and lower...gracefully,
> my device sank to the ground and the monitor became a stone like the
The buzzing and clicks indicate that something was shorting out. Our
advice re high voltage insulation was sound:)
> I am not going to open the monitor for another 24 hours, but I am
> *hoping* that this time it is clearly the HOV transistor that failed.
> If it is, I can replace it...if it isn't, well, I really hope it isn't
> something inside that damned epoxy-filled flyback unit. Then there is
> no hope...
> If I replace the HOV transistor, can I use a more rugged one? If I
> don't overly care about the exact output voltage, does the particular
> transistor matter too much? I want to get one that's close...but that
> will survive. Should I get a 6-pack? :P
It usually is just the LOPTR. You often can use a more rugged one, but
it still wont cope with what youre doing. Read what I wrote about your
R network being woefully inadequate. Make an R network that a)
withstands the voltage, and b) limits current to what the monitor can
provide. Ditto for wire insulation. Then dont go anywhere near it. We
dont want your personal insulation breaking down as well.
> does the particular transistor matter too much?
Erm yes :)
Please read up on EHT safety before continuing. It would be foolish