Re: New Vector Monitor Project: Deflection I & V Measurments

Nice! Now someone give this man a G-08 so we can see what their max frequency is. Im sure
it isn't all that greater than the 6100 tho. From what I remember the G-08 is the
'fastest' of the XY monitors so the replacement monitor should be designed to keep up with
the Sega XY games as well?

Mendel Pearl wrote:
>
> I have done a simple test too see what maximum frequency the WG6100 amplifiers
> can operate until they start to phase shift or decay.
> I connected a sine generator to both inputs and input a 8V t/t wave, so the
> display showed a straight, 45 degree slanted line.
> When I increased the freqency, the display started to distort at about 5Khz.
> (the straight line became more circular).
> At 10 kHz it was almost a full circle (90 degree phase shift).
>
> Does this mean it is not nessesary to create an amp which can amplify signals up
> to 100kHz since the original seems to fail at 5kHz?
>
> Just my 2 cents.
> Cya!
>
> "James Nelson" <nelsonjjjj@didactics.com> on 11/05/99 04:13:11 PM
>
> Please respond to vectorlist@lists.cc.utexas.edu
>
> To: vectorlist@lists.cc.utexas.edu
> cc: (bcc: Mendel Pearl/Matra exiTel/nl)
> Subject: New Vector Monitor Project: Deflection I & V Measurments
>
> Ok, I just measured I & V on Tempest: Here is the data:
>
> Procedure:
>
> 10X scope probe used, X&Y measurements are at output with respect to ground,
> so they are off by about 2 volts due to Voltage drop across the shunt
> resistors. Current measurements taken by measuring voltage across 1.5 Ohm
> shunt resistors with scope. 2 Volts typ peak across 1.5 Ohms, 4Volts Max.
>
> Data:
>
> Voltages X&Y approximately +/- 25V peaks
> Current: typical peaks about +/- 1.3 Amps
> Current: Max peaks about +/- 2.6 Amps
>
> Conclusions:
>
> Without a precise RMS measurement, I'm going to estimate a typical RMS Power
> output of
> about 25 Watts.
> Peak Instantaneous Power output was 65 Watts.
>
> The LM3886 can do 68 watts continuous into a 4 Ohm load and 135 watts peak.
> To compare these numbers directly, one would need to know the impedance of
> the yoke at the frequencies used (approx. audio up to 100 kHz) So far, it
> still looks like it might be a good match to me, and worth testing out.
>
> Comments Graciously Requested
>
> James
>
> ----- Original Message -----
> From: James Nelson <nelsonjjjj@didactics.com>
> To: <vectorlist@lists.cc.utexas.edu>
> Sent: Friday, November 05, 1999 8:12 AM
> Subject: Re: New Vector Monitor Project: LM3886
>
> > Rodger, you're not raining on a parade at all, and don't stop criticizing
> > designs, otherwise I won't get something that works.
> >
> > The specs on the LM3886 looked ok to me, but maybe it's time for me to do
> > some actual current and voltage waveform measurements on Tempest to see if
> > it's too demanding for the use of such a device or not. I don't think
> that
> > we are running over 50 watts of power through the yoke.
> >
> > I'll let you know what I come up with on those measurements!
> >
> > Thanks,
> > James
> >
> >
> > ----- Original Message -----
> > From: Rodger Boots <rlboots@cedar-rapids.net>
> > To: <vectorlist@lists.cc.utexas.edu>
> > Sent: Friday, November 05, 1999 1:53 AM
> > Subject: Re: New Vector Monitor Project: Microprocessor, etc...
> >
> >
> > > James Nelson wrote:
> > >
> > > > I'm looking carefully at the National LM3886 Power OP AMP for direct
> > yoke
> > > > drive, and it doesn't cost the $100+ each like some of the other
> <choke>
> > > > cool ones do, and it has all kinds of protection circuitry, and Class
> AB
> > > > circuitry.
> > > >
> > > > Rodger is going to look at the LM3886 to see what complaints he might
> > have
> > > > with the device, and I might throw up a proposed 1st order schematic
> for
> > > > that circuit soon.
> > >
> > > Well, I've looked at it and have some serious questions if it has the
> raw
> > balls
> > > needed for a color vector monitor. B&W, maybe, but I think it's going
> to
> > keep
> > > shutting down running color, even with massive cooling. Especially on
> > games
> > > that overscan the monitor.
> > >
> > > Yeah, shutting down will protect the IC, but how many times can you
> > collapse the
> > > sweep on a game before you burn a big cross in the middle of the CRT.
> > We're not
> > > talking losing one half of a screen here, we're talking collapsing into
> a
> > line.
> > > Or worse yet, a dot if both channels dump at the same time. The spot
> > killer had
> > > better be damn fast.
> > >
> > > I hate to keep raining on this parade so would someone please tell me
> I'm
> > full
> > > of it (and be ready and able to prove it!) already?
> > >
> > >
> >
> >
Received on Fri Nov 5 11:03:03 1999