Re: Ampliphone HV-other options?!

Hi David!

As I mentioned to Clay, you only need a yoke to bench test a raster scan
monitor chassis. Unless you want to load down the screen transistors,
the chassis will perform just fine. I suspect one could use load
resistors for the yoke's vertical, but the horizontal deflection is a
tuned circuit, and thus there really is no shortcut that I am aware of
for bypassing the yoke.

One is able to run an XY chassis without a yoke, as the thing is really
just an stereo audio amp, and some load resistors would work fine. If
you short the inputs to ground, there technically would be no output and
thus you could even not have anything hooked up to the yoke socket. The
Cinematronics monitor makes a loud statement (a metallic sticker) on
their monitor NOT to run them without the output transistors plugged in,
however they do talk about running the monitor without the yoke plugged
in...the output transistors are then unloaded, and less likely to fry.
Your mileage may vary.

John :-#)#

"David Shoemaker (Comforce/RhoTech)" wrote:
>
> What I want is a simple way to bench test Ampliphone sets without having to
> haul a tube out of a cabinet. Is there a safe way to hookup a deflection /
> HV set without having the tube?
>
> I kind of figured no as I would also have to have the deflection coil and
> tube socket hooked up to something.
>
> I was thinking about trying to just mount the tube in a WG frame and find
> ways to mount the HV / deflection boards to that. Kind of wrap it all up as
> a package for ease of testing.
>
> David
>
> > -----Original Message-----
> > From: owner-vectorlist@mcfeeley.cc.utexas.edu
> > [mailto:owner-vectorlist@mcfeeley.cc.utexas.edu]On Behalf Of Zonn
> > Sent: Friday, June 11, 1999 2:36 PM
> > To: vectorlist@mcfeeley.cc.utexas.edu
> > Subject: Re: Ampliphone HV-other options?!
> >
> >
> > On Fri, 11 Jun 1999 13:20:37 -0700, you wrote:
> >
> > >> We could hook up (backwards) a 50v
> > >> (25vct) transformer to the output of the 50v transformer
> > supplying the
> > >> power to the monitor to get 120volts, but it's probably
> > easier just to
> > >> find an isolation transformer. Up until the most current
> > generation
> > >> of WG monitors, one was required, there must be many
> > floating around.
> > >>
> > >I think we can get 1:1 isolation transformers for probaly
> > $10-12 each.
> > >Maybe even less $$$ since we don't need as much current as
> > "usual" (not
> > >driving the color guns and deflection off it).
> > >
> > >So is it "safe" for an HV transformer to have its anode
> > coupled to ground
> > >through a resistor? (To just burn off the HV output without
> > having to hook
> > >it up to an actual CRT.) Might not want to be generating
> > soft x-rays while
> > >figuring things out...
> >
> > I was thinking of hooking it up to an actual CRT. I need to measure
> > the filtered peak voltage generated by the HV section. I'm not sure
> > my voltmeter would follow the strange waveforms that might be
> > generated without the filtering. It is a Fluke, and it is supposed
> > being measuring "True RMS", but still I'm interested in peaks.
> >
> > I was under the impression the x-rays are generated by the electron
> > beam from the gun. I only want to use the CRT as a big capacitor
> > (with an over 30kv breakdown voltage). I don't think just having a
> > big capacitor charged up to 30kv will generate x-rays, that sounds too
> > much like free energy.
> >
> > -Zonn
> >
> > FWIW: I'm currently moving full-time now (still looking for a place,
> > everything is going from my current condo into a storage unit, for the
> > time being.) I'm not sure I'm going to have a decent work bench
> > throughout the summer. It could be a few months before I can wire
> > something up...
> >

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