REPLACING THE POWER SWITCH ON A COMMODORE MONITOR
               Latest updates and corrections: 7-17-2014

     The standard CBM 1084 series and 1902A monitors made by Philips 
have a separate power supply board mounted on a slide-in plastic tray. 
The power switch is fastened with two screws to the front end of that 
tray so it sits just behind the front panel push button assembly. Four 
wires connect the switch to the chassis. Note the position of the color 
coded wires and install them the same way on the new switch. It's best
to remove the old switch but leave it's wires connected, then mount the 
new switch and transfer the wires one at a time so you don't make any 
wiring errors. There are other monitors made by a different company and 
their switch mounts are different. Check the photos to see which one 
matches your monitor.

MONITOR DISASSEMBLY     

     Position the monitor face down on a cloth or newspaper to prevent 
scratches on the front panel or tube face. Be mindful that the 
fold-down door on the bottom front panel is easily broken! Five screws 
must be removed to pull the rear cover off the monitor. Disconnect the 
speaker plug (two on stereo monitors) from the upright sub-board 
as you remove the rear cover. If you fail to do that, it may break the 
connections to the speaker(s). 
     For the Philips monitors: To replace the switch, you need to
remove the power supply board tray from the cabinet. Unsolder the two 
braided ground straps from the bottom metal shield on the main board. 
The release tab for the tray is inside a small square cutout underneath. 
Push the release in slightly with a small screwdriver as you pull the 
tray rearward. As you are sliding the tray out, unplug any connectors 
that keep the board from being pulled all the way out. The tray may 
snag on its wiring, so work carefully. Other monitors such as the 1084D 
and S-D mount the switch to the front panel, making that switch easier 
to replace. 

REPLACING THE SWITCH (Philips)

     The mounting holes of the replacement switch may be misaligned 
with the holes in the plastic tray by a fraction of an inch. If so, 
the holes in the tray may be trimmed (elongated) outward slightly 
with a thin sharp knife or a tiny round file so the switch will fit. 
Although the new switch is designed for machine screws, the original 
self-tap screws will work fine. Depending on the switch you use, you 
may need to also trim some of the tray plastic so the switch will 
fit into that space without binding on the plastic. Cut the wires, 
one at a time, from the old switch close to its terminals and solder
them to the new switch. You will probably need to cut the plastic 
strain relief holding the AC cord to the plastic tray and the other 
one that bundles the wires. Re-fasten the cord to the tray after the 
wires are soldered to the new switch. Note that the cord must fit back 
down into the slot in the tray when it's slid back into place. 
Reconnect any plugs your removed earlier to the PS board as you slide 
the tray forward into place. Dress the wiring out of the way if the 
tray snags or binds. With the tray in place, try the switch a few times 
to make  sure it latches and unlatches properly before going any 
further. If it's OK, resolder the shield braids to their previous places. 
As you reattach the rear cover, don't forget to reconnect the speaker 
plug... and don't bump the board on the back of the CRT (picture tube)!

THE CBM 1902 (non-A model) AND 2002

     These monitors were made by Fujitsu and have a different layout 
for the power switch than a 1084. It mounts directly to the front 
panel (two screws) and uses only two wires. Place the monitor face 
down on a cloth. Six screws must be removed to pull the rear cover 
off the monitor. Raise the cover slightly and disconnect the speaker 
plug by squeezing/pulling the connector, then remove the cover. Note 
how the original power switch is mounted and how the wires are 
connected with a small PC board. That board can be discarded along 
with the switch and the two wires soldered directly to two terminals 
of the new switch. The other two terminals of the switch are unused.
     The original installation didn't use the switch mounting holes 
but just two large washers as clamps at the edges of the switch. The 
new switch can be mounted in a similar fashion. However, a slightly 
longer switch actuator may not allow it to release properly when 
turned off. If so, you can use extra washers underneath the edges as 
spacers or you can trim a small amount off the end of the switch 
shaft, no more than 1/8"! I prefer shims because once you trim the 
plastic off the switch, you can't put it back if you took too much. 

THE AMIGA 1080, CBM 1084S-D and similar models

     This monitor uses a completely different Daewoo (Korea) chassis. 
The power switch mounts on the front panel, similar to the 1902 and 
2002 versions. The small PC board must be left in place as it also 
connects to the front panel power indicator LEDs. The switch wires 
will be cut off and soldered directly to the terminals of the new 
switch. As before, you can use a few washers as shims if the switch 
actuator is too long and it doesn't release all the way when turned 
off. An alternative would be to trim no more than 1/8" off the end 
of the switch shaft. If you cut off too much, you'll have to fix it 
somehow, i.e. lengthen it to make it work. A bit of stiff sleeving 
slid onto the actuator shaft should work for that. Note that only 
two switch terminals are used on some monitors although the switch 
itself has four. Other monitors use all four switch terminals. I 
have included some photos of the various switch replacements. One 
of them should match what you have. 

Ray