Re: I,Robot help...

  It doesn't run the 145VDC to the degaussing coil, it has an entirely
different power supply for it that is basically the same as on monitors
(PTC Thermistor off 120VAC). I can't think of a reason why they would
have duplicated that circuitry on the switching power supply and took it
off of the monitor main supply other than load. The only other reason
was that it was targeting the upcoming Amplifone Raster Monitor which
didn't have the degaussing power circuit on the monitor at all AFAIK.

Jess M. Askey
*ASCII Solutions - Software Design and I.T. Services*
3315 Buntwing Ln
Fort Collins, CO 80524
307-760-5270
http://www.ascii-solutions.com <http://www.ascii-solutions.com>

On 12/7/2010 12:39 AM, Rodger Boots wrote:
>
> It's not that the degaussing coil is too much of a load---if you run
> DC to a degaussing coil it would magnetize the CRT, not demagnetize it.
>
> On Dec 6, 2010 10:19 PM, "Jess Askey" <jess@askey.org
> <mailto:jess@askey.org>> wrote:
> > Just a followup (Thanks to Joe M. for volunteering to help).
> >
> > I sort of dug through the manuals and found a number of very small
> > photos around the web so I think I have it straight.
> >
> > The I,Robot dedicated cabs definitely had Disco monitors in them. The
> > odd part is that Atari just ran the 145VDC directly into the monitor's
> > 120VAC connector. In reality just about all monitors of that era
> rectify
> > the 120VAC into ~170VDC and then regulate it back down to 120VDC
> > internally. Running the 145VDC into the 120VAC input simply passes the
> > 145VDC through a pair of the bridge rectifier diodes and (-1.2V) and
> > then the monitor regulator would take it down further to the main
> 120VDC
> > rail. So, this works fine and the monitor regulator generally runs
> > cooler this way too.
> >
> > As far as the connector numbers, they are a wreck, nothing really
> > matches, not even on the I,Robot schems. Clearly a hack job. :-) But
> not
> > as much as the next game's (Firefox) monitor (Amplifone Raster)
> > configuration, I think that one takes the cake for messy and unreliable.
> >
> > So, in reality, just as Mike said below, it should be pretty easy to
> put
> > just about any 19" monitor into an I,Robot as a replacement. You don't
> > even need to put in an extra isolation transformer if your switching
> > power supply is still running and you use the 145VDC output as it is
> > already isolated.
> >
> > NOTE: the I,Robot switcher has circuitry for the degaussing coil which
> > I would imagine is too much of a load for the 145VDC switcher, so, you
> > should disconnect your degaussing coil from the monitor's internal
> > circuitry and hook it up to the switching power supply degaussing pins
> > instead. I don't think the switcher would take the load of the
> > degaussing very long before dying or blowing a fuse at the least.
> >
> > If you are not a purist, it would certainly be more reliable to go the
> > exact route that Mike did and just put in an extra isolation tranny and
> > use the entire new monitor separately from the switching power supply.
> > While you are in there, you might as well put a PC switching power
> > supply in there too. That is certainly the most reliable config.
> >
> > whew.... back to fixing my switching power supply now. :-)
> >
> > jess
> >
> >
> >
> > Jess M. Askey
> > *ASCII Solutions - Software Design and I.T. Services*
> > 3315 Buntwing Ln
> > Fort Collins, CO 80524
> > 307-760-5270
> > http://www.ascii-solutions.com <http://www.ascii-solutions.com>
> >
> >
> > On 11/23/2010 5:38 AM, aubhtr@aol.com <mailto:aubhtr@aol.com> wrote:
> >> I replaced the monitor in my I, Robot with a WG 4900. I just added a
> >> seperate isolation transformer and ran power to it.
> >> I do have a working Disco chassis that came from the original monitor
> >> available. The horizontal width coil is cracked and needs to be
> replaced.
> >> Mike
> >>
> >>
> >>
> >> -----Original Message-----
> >> From: Jess Askey <jess@askey.org <mailto:jess@askey.org>>
> >> To: rasterlist <rasterlist@vectorlist.org
> <mailto:rasterlist@vectorlist.org>>
> >> Sent: Mon, Nov 22, 2010 10:45 pm
> >> Subject: RASTER: I,Robot help...
> >>
> >> Can someone with an I,Robot help me out... Im trying to find a
> >> replacement monitor and keep mine stock and I can't really find any
> >> docs that go into detail about the monitor in the I,Robot.
> >>
> >> Here is what I find in the docs....
> >>
> >> 1. the monitor is powered by the Switching power supply and gets
> 145VDC.
> >> 2. Because of the power configuration, the monitor does not need an
> >> isolation transformer (the isolation is actually the switching power
> >> supply)
> >> 3. The I,Robot schematic package shows..
> >> a. monitor power going from the Switching power supply to P26 on
> >> the 'Video Display'.
> >> b. degaussing coil going from the Switching power supply to P2 on
> >> the 'Video Display'
> >> c. the RGB+S inputs from the game PCB to J205A *and *J205B
> >> 4. Looking at the various disco monitor pinouts on the internet, I
> >> can't find any monitor that has these connectors (P26, J205, J2)
> >>
> >> I looked at these monitors on arcarc...
> >>
> >> TM-210 Disco Display
> >> TM-254 Amplifone Raster Monitor
> >>
> >> Neither seem to have these connector designations or pinouts. I
> >> thought perhaps that the monitor was simply hacked and they fed the
> >> 145VDC directly into the 120VAC input. But I just haven't been able to
> >> find any monitor documentation that matches the I,Robot schems.
> >>
> >> So... with all that... can someone with an I,Robot pop the back off
> >> and take some detailed pics of their monitor and see what model they
> >> have and if it is modded in any way???
> >>
> >> What a great Thanksgiving project!!!!! :-)
> >>
> >> thanks
> >>
> >> jess
> >>
> >>
> >>
> >>
> >>
> >> --
> >>
> >> Jess M. Askey
> >> *ASCII Solutions - Software Design and I.T. Services*
> >> 3315 Buntwing Ln
> >> Fort Collins, CO 80524
> >> 307-760-5270
> >> http://www.ascii-solutions.com

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Received on Tue Dec 7 19:58:38 2010