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home>>Tech tips>>Tech tip #5
Marquee Anamorphic Mods
The anamorphic mod is required on most Marquees to extend the range of the vertical size adjustment to allow for shorter raster heights needed for 16:9 DVDs and correct geometry for HDTV. The mods fall into two categories depending on the version of rear heat sink in a particular chassis; hinged rear heat sinks found on newer units, and fixed rear heat sinks found on early Marquees.
For Hinged Rear Heat Sinks
On newer Marquees, the Vertical Deflection Module is located on the rear heat sink behind the blue CRT (see PIC 1). The mod requires a phillips screwdriver, soldering tools, and three 56k ohms, 1/4w, 5% resistors. Remove the Marquee's top gray metal covers and remove four phillips screws across the top of the rear heat sink, which should permit you to open the rear heat sink on its' hinge; do not allow the yoke wires to be pulled or stressed. Locate R704, R804, and R904 on the vertical board, they are close to the yoke molex pins and should be marked orange, black, orange to denote 30k ohms. Remove these three resistors (see PIC 2), this can usually be done without pulling the board from the heat sink. Take care not to damage the foil traces of the PC board. Form he 56k resistors into U shapes with short leads (see PIC 3), and solder them into the places where the 30k ohm resistors were located (see PIC 4). Reassemble the unit with covers, and power up the unit. Next, go into UTIL, 9 and enter the passcode 0901 for the Service menu, select 3, and match red and blue raster heights to green so as to place the least load on dynamic convergence. Touch up geometry and convergence as needed and the mod is complete.

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For Fixed Mount Rear Heat Sinks
Older Marquees employed vertical boards mounted with screws, no hinges. Remove covers as before, and pull the vertical board from the chassis (see PIC 5). Locate R41, R47 and R52, they are 10k ohm resistors located near IC U7 and are marked brown, black, orange to denote 10k ohms, but need to be around 8200 ohms. The technician can either replace the three resistors with 8200 ohm, 1/4 watt, 5% or bridge them with 47k or 50k resistors to achieve the same effect. We have elected to bridge R47 (see PIC 6) with a 47k ohm resistor (see PIC 7 and PIC 8); after bridging or replacing all three resistors remember to match raster heights in the Service menu.

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Tim at E-Tech Systems Phoenix
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