Converting a Cinematronics Solar Quest Monitor w/ 64-Bit Intensity PCB Back
to a Standard Cinematronics Monitor

By Rich Potts

I promised Tom McClintock and Mark Shostak I'd document this for them when
I got around to it, so here are the instructions on the conversion.  

The monitor in a Solar Quest uses a 64-bit intensity PCB for the screen
graphics.  To use this board, there are modifications done to the main
monitor PCB, as well as components that are omitted to accommodate the
intensity PCB.  Simply unplugging the intensity board will not make the
monitor work correctly in a Star Castle, or any other game that uses this
type of display.  You will need to replace several components that do not
exist on the Solar Quest monitor, but are needed on the regular version
to make it run properly.  Here is what you will need for this conversion:

(2)  2N5550 transistors for locations Q1 & Q3
(2)  10K ohm 1W Resistors for locations R7 &R8
(1)  2.2K ohm 1/4W Resistor for location R9
(1)  10K ohm 1/4W resistor for location R22
(1)  5.6K ohm 1/4 W resistor located on the back of the PCB w/ the
     brightness pot

To remove the 64-bit intensity PCB, unplug the molex connector from it, as
well as the ribbon cable, and unscrew the 2 bolts that connect it to the
chassis.  You will have to desolder the five wires (from the molex connector)
that are connected to the main board as they are no longer needed, and you
will be using some of the holes they were in.

In order to work on the Cinematronics monitor PCB, you should most
certainly remove it from the monitor itself. This is easily done by
unplugging the deflection transistors, yoke wires and anything else
attaching itself to the PCB.

First thing to do is start with the easiest.  There is a black molex
pigtail that plugs into the main PCB and the molex plug from the high
voltage box.  This pigtail harness is not needed.  Unplug it from both,
and plug the molex from the HV unit directly onto the main PCB.  That
takes care of the HV portion.  Next, after you have found the locations of
the omitted components, you will need to desolder the holes to expose them,
as they will probably be covered.  All of these holes will be located on
the right side of the PCB (looking at it with the screen facing away from
you, component side up), to the right of the 34 pin cable connection and
above the brightness pot.

The first, and easiest to install will be the 2.2K ohm resistor at R9, the
10K ohm resistor at R22 and the 2N5550 transistors at Q1 & Q3.  They are
not obstructed or connected to any other component.  Everything else is in
proximity or deals with the brightness pot.

You will notice that the brightness knob is installed upside down compared
to a standard Cine monitor setup.  This will have to be desoldered and
mounted from the bottom, with the dial on the component side, not the
solder side.  Desolder the pot, remove the nut and washer and pull it from
the board.  The resistor attached to one of the legs is not needed, so you
can remove it.  You will see that the connecting pins that attach to the
board are nothing more than wire soldered to the pot legs that jumper to
the PCB.  You should definitely have 2 of them intact.  I will explain
which 2 in a following paragraph.  Also, one of the tabs has been bent up
to accommodate a slot in the PCB.  It will have to be bent back, and the
tab on the opposite side will now need to be bent up.

While the pot is removed from the board, you will want to install both the
10K 1W resistors at R7 & R8.  You can do this whenever you like, it is just
easier to do with the pot out of the way.

You will now need to flip the monitor PCB so that you are facing the solder
side of the board.  The 2 pins that need to be intact on the pot will be
the ones that go in the left and middle holes when you mount the pot.
There are probably other ways to do this, however I was referencing a good,
working monitor while I was doing this, and this is how it was set up.
The leg on the right of the pot is where you will want to attach one end
of the 5.6K ohm resistor. I have seen other monitors without this resistor,
and just the wire leg, but never both simultaneously.   With this done, you
can slide the pot into place, and solder the 2 wire legs to the board.  Put
the washer & nut back on and tighten the nut.

This leaves the other end of the 5.6K ohm resistor.  You will need to find
the 1N4003 diode at location D4.  Solder the leg of the resistor to the leg
of the diode closest to the middle of the PCB.  

The only other difference I noticed was that everywhere there was a wire
jumper on a standard monitor, there is a resistor with one black band in
the middle of it on the SQ monitor.  I did nothing to these at all.  

That is it! You can now put the monitor in any other Cinematronics game
that uses the standard setup.  I have mine in my Space Wars, and it works
very nicely.  Happy gaming.