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Discussion Starter · #1 ·
My Electrohome 9500LC was working perfectly until Friday night when I heaRD AN ARCING SOUND From PROJECTOR, THE BEAmS WENT OUT for a second and came back on with a lime green discoloration to the image.

If I use the 3500 Kelvin temp setting it looks almost correct.

What can I do?

Bill
 

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Say Bill


The arc may have weakened the red neck board; see if adjusting gray scale helps:


For gray scale setup for a Marquee projector, try this, this

is done in a darkened room:


a) Warm up the projector for 30 minutes. Input a signal

of 31khz or higher, or push UTIL, 1, 6, 2 for an internally generated signal of 31khz


b) Set Contrast to 45 and Brightness to 50


c) Go into Service Menu, push UTIL, 9, 0901, 1 (color

temp), 2 (6500^) Note existing Drive and G2 values

on a pad of paper before changing the values!


d) Set Red Drive to 35, Red G2 to 60. Push Enter to

continue


e) Set Green Drive to 90, Green G2 to 60


f) Set Blue Drive to 50, Blue G2 to 60


These are typical Drive and G2 (background) levels as found

in new projectors. Using the # button, bring up the test pattern of different intensity gray blocks, also known as the Stairstep pattern.


g) Look at Stairstep for each color; raise or lower G2 for

each color until the second darkest square is just lit,

but the darkest square is not lit (lower left corner)


h) Push Enter until all three colors are on. Instead of

Enter, if you push Tint you can adjust each color while

all three colors are on. Raise or lower Drive for each

color until peak whites look okay (bright squares of the

Stairstep pattern. The Drive adjustment interacts some

with G2, so repeat step g) as needed.


i) Inability to see the second darkest square with G2

below 75 for any color indicates a worn or damaged tube.

The need to set Red Drive above 60, or Blue Drive above

75 also indicates weak tubes.


If you cannot get sufficient peak red output then a technician may need to try swapping neck boards, which are the final video amplifier stages.
 

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Discussion Starter · #4 ·
Thanks for all of the help, Tim. Had Hi-Rez guy up yestedrday after notifying them of the results of the testing you suggested and indeed it was the blue tube neck board that had become defective. Its help like this that makes this board and its members great. Bill
 
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