Re: I,Robot help...

From: Jess Askey <>
Date: Mon Dec 06 2010 - 23:18:51 EST

  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 M. Askey
*ASCII Solutions - Software Design and I.T. Services*
3315 Buntwing Ln
Fort Collins, CO 80524
307-760-5270 <>

On 11/23/2010 5:38 AM, 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 <>
> To: rasterlist <>
> 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

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Received on Mon Dec 6 23:19:16 2010

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