RE: Amplifone Design... Wonders me

From: Bret Pehrson <bret_at_infowest.com>
Date: Tue Mar 09 2004 - 18:08:44 EST

I go no wobble on my pretty much stock Amps. (2 19" and 1 25") in 2 SW and 1
MH.

> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of mypearl
> Sent: Tuesday, March 9, 2004 12:36 PM
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Amplifone Design... Wonders me
>
> Hello Zonn,
>
> Nice to read your extensive reply about amplifone regulation.
>
>
> > No low voltage regulation.
> >
> > I noticed this a long time ago. Every properly working
> Amplifone I've
> owned has
> > had a less stable picture than every properly working WG6100.
>
> So it is normal to have the image wobble at the outlines over
> maybe as much
> of 1/4-1/8 of an inch... ???
> It is SO annoying... the wobble is made up of the difference
> in X and/or Y
> input frame frequency and the 50Hz (60Hz in US). The
> amplification factor
> (gain) of the amplifiers is modulated by this frequency. A 53 Hz frame
> screen looks ugly (3 Hz wobble), 50 or 70 and greater frame
> frequencies look
> better.
>
>
> > The Amplifone's whole reason for existence was price
> reduction (and maybe
> supply
> > problems with the WG6100 as well). The first thing they
> got rid of was
> the low
> > voltage power regulator -- they replaced it with a wire.
> The second thing
> they
> > got rid of was the high voltage regulator, it was replaced by a
> > feroresonance(sp?) design that does not regulate as well as
> an active
> regulator.
>
> I'm not so sure this was done to make things cheaper.
> Star Wars wants to be able to defocus the beam to create some special
> effects. Notice how the enemies laser shots are defocused and
> therefore look
> really cool and cloudy (in stead of a bunch of lines) such as
> i.e. Tempest.
>
> A little history I once heard telling:
> First Atari deviced a HV supply in which a vacuum tube could
> change the
> focus, but ofcourse this was not feasible for mass production.
> Then they decided they could also overdrive the RGB inputs,
> causing the beam
> current to go up in such way the HV supply voltages drop and
> the beam is
> defocused.
>
> A very well regulated HV supply doesn't work well (or too
> well) in this
> case. Maybe this is why the amplifone has it's kind of
> regulation... to
> enable 'blurry' vectors.
>
> > From a manufactures point of view, this made the Amplifone
> a much nicer
> design.
> > Wires are much more reliable (and cheaper!) than the highly
> unreliable low
> > voltage regulator design in the WG6100. In the HV section
> the poor design
> of
> > the WG6100's HV section was also replaced by a wire (ok a
> coil, but it's
> just a
> > long wire wrap around something).
> >
> > If it wasn't for a manufacturing defect in the Red HV
> transformer, these
> > monitors would most likely have been very reliable.
>
> While the deflection board is essentially the same as that of
> the WG61xx
> range... Maybe the TO3 mounting made all the difference...
>
> > From a collector's point of view the removal of active
> regulation in the
> two
> > critical parts of the monitor's design leads to shaky
> vectors and a screen
> that
> > blooms when more vectors are drawn (leading to even more
> shaky vectors).
> >
> > In an arcade most of the players aren't going to pay much
> attention to a
> little
> > shakiness on the display, as long as the game is working,
> they'll play it.
> >
> > But when it's in your collection it can bug the hell out of you!
> >
> > The solutions are to regulate the LV and HV sections
> yourself. By using a
> lab
> > supply like you did, you restored regulation in the LV
> section. Another
> > possible solution is to back fit a LV2000 (you'll need to
> mount a couple
> of
> > heatsinked power transistors somewhere.)
>
> Well, if it is really normal for the Amplifone to have some
> shakyness, I'll
> just HAVE to do just that...
> It looks SOO much better connected to the lab power supply... really
> rock-solid!
>
> > For the HV section your most likely best bet now is to use
> one of the
> newly
> > designed HV replacements Fred's come up with. Before that
> it would mean
> > retrofitting a WG6100 HV section into a Amplifone, but the WG6100 HV
> section
> > itself, was not a great design from both an engineering and
> reliability
> > viewpoint. It'd be better to just get the Wintron HV xmfr.
>
> I definitely would..
>
> Does anyone have the WG61xx replacement HV module installed?
> It would be interesting to know wether you really loose the
> defocused enemy
> shots and explosions in Star Wars due to the better regulation!
>
> > The Wintron HV will restore the reliability of the
> Amplifone, but it still
> lacks
> > decent HV regulation.
>
> ... If that ia actually what we want... :)
>
> Mendel
>
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Received on Tue Mar 9 18:08:46 2004

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