Electrohome Marquee
Series
CLM/Microprocessor board
Below is a picture of the CLM or microprocessor board. This is where all of
the control functions of the projector take place. The pix below is of a Marquee
8110. There are slight differences between the 8000, 8110 and 8500 control
boards, but the functions are the same. The main difference between the
8500/9500/9000 control boards and the other models is that the higher end units
have a second daughter board installed for the astigmatism (or ‘Stigmator’ as
Electrohome calls it) as outlined in the red rectangle below. Without this
board, the astigmatism controls in the service menu become disabled, however the
set will still function.
As with the HDM board, the daughter boards can develop bad contacts and cause
intermittent operation of some functions or projector power-up. Socketed chips
on this board can also get bad contacts. To reseat the chips, simply push down
HARD on each chip so that it sits firmly in its socket.
The memory battery on the board can go bad. This is a lithium battery that
measures 3 volts. If the battery voltage drops below 2.8 volts, you stand a
chance of losing the convergence memory without warning, or the set may have
erratic operation.
The rear panel of the CLM shows error LEDs that give a hint as to where the
problem in the set lies. Most of these error codes are straightforward, H fail
for a bad horizontal board, V fail for a bad vertical board, etc. AS with any
other set however, the LEDs are not perfect indicators of all fault conditions
in the set, so here’s some other errors that I’ve found with the Marquee sets:
Error lights sequentially flashing back and forth- bad connection on a chip
on the CLM board
Multiple LEDs on, indicating possible multiple board failure- caused by a bad
VIM (RGB input) board.
No picture, but no error lights on- This can be due to any board being bad in
the set. There are a number of circuits that will shut down the HV power supply
which will cause no picture, but you may not see an error light on the back of
the set. Failure of the HV section in the set will also not be indicated on the
CLM board error LEDs.
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