Re: I,Robot help...

From: Rodger Boots <>
Date: Tue Dec 07 2010 - 02:39:48 EST

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" <> 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
> <>
> 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 Tue Dec 7 02:40:17 2010

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