Usually it takes no money and just a little
bit of time and care to fix
ghosting problems. Almost every
dimmer has a method for doing this. It is best to find the documentation for your particular
dimmer. It is often a simple adjustment but can sometimes be caused by a parts failure.
On an EC Quad rack you should be able to fix the
ghosting by the following process. This assumes the problem is with the dimmers and not the
console or some kind of converter.
Each vertical column of dimmers is controlled by a PC341 ramp module in the bottom card cage. The three ramp modules look like the illustration and are near the center of the card cage. The left ramp module controls the left column of dimmers, center controls center,
etc.
Starting with the left column, attach a 500-1000
watt fixture to one of the dimmers circuits. Make sure the control
console is turned off or the master is down.
The
fixture ghosts.
The high and low
trim pots are behind the 2nd and 5th faceplate slots as shown. Use a very small slotted screwdriver (preferably with a plastic shaft since you are inserting it near a live pc board) to adjust the low pot. You will have to get down on your hands and knees with a flashlight to get the screwdriver lined up. Note the relative position of your screwdriver in case you have to
return to the original setting. Be very careful not to use much front to back pressure because the pots are very fragile and are just held on to the pc board by their leads with no other support. I can’t remember which way to turn the pot but with very little rotation you will either see the load dim or brighten. This not a multi-turn pot and is very sensitive to adjustment. Usually an eighth of a turn or less will make something happen.
Sometimes these pots will become intermittent after many years and cause an entire column of dimmers to malfunction. This low end adjustment can interact with the high end adjustment, so be sure to carefully run the
channel up and down on the
console while observing the load before you move to the next column of dimmers.
If you end up bending the pot backwards and need to straighten it up, you MUST kill
power to the rack before you remove the top left module retaining screw and pull the ramp module out to
bend it back. If you do not feel comfortable killing the
power or removing the module, please seek help from a qualified person.
This may be more information than you need.