Electrohome Marquee Series

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      >> Tim Martin Modified LVPS Installation
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Here is a breakdown of the innards of the Electrohome Marquee series of projectors. Note that there is a lot of excellent information at www.etechvideo.com that covers a lot of setup, tube replacement and general info. I will not duplicate that information, but will give a general overview of the set and the layout of the boards.

Generally speaking, boards from later model Marquee projectors will work in the earlier sets, but earlier versions of boards may not work properly in later models sets.

For example, the H board from a Marquee 8000 will work in a later 8110 or 8500, but the H size control will not increase higher than the 50% point. The onscreen display will increase, but the actual raster width will not. Similarly, the VIM from an 8000 will give a picture in an 8110 or 8500, but the picture may be dark and the test patterns will not work properly. Either board from a later model will work fine in the 8000 however.

Some boards like the LVPS and HVPS and the CRT sockets are compatible across the various models, but the overall specifications and performance may be slightly compromised.

Generally speaking as well, with the exception of the tubes, lenses and CRT sockets, the modules are interchangeable between the Marquee 8 and 9” sets. The CRT sockets have a different beam limiter setting between the 8 and 9” tubes, and the 9” tube socket cut-out is slightly different than the 8, so the 9” sockets will not fit onto an 8” tube.

Front View

The front metal plate covering the power supplies comes off with the removal of four screws. This exposes the HV and LV power supplies. Each of the power supplies comes straight out of the set by removing the two screws and then pulling the supply out. THE HV supply has a thick red cable that runs through the chassis to the HV splitter. The HV lead unscrews out of the HV splitter via a bayonet type fitting.

It’s a good idea to touch the metal tip of the HV supply to the metal chassis after you take it out of the splitter to discharge any residual voltage stored in the HVPS, although under normal circumstances there’s no voltage there.

The LVPS has a row of red LEDs on the front of it. During normal working conditions, these LEDs should be off. They may flash briefly as you power the set up or down. It is normal for the fans to spin slowly (at about 1/3 normal speed) when the projector is turned off. This is normal.

There are no user serviceable parts in either of these supplies. The LV supply powers the various areas of the set, and typically the set will go dead if it fails. Note that a short somewhere in the set will cause relays in the power supply to pulse about once or twice a second as the LVPS senses an overload condition. To find the short, remove modules in the set until the LVPS stops pulsing. The focus board and back heatsink/vertical board commonly short out, causing an overload condition.

The HVPS provides the high voltage to the CRTs. There are two styles of HVPS. The older series used in the 8000 and 9000 series of sets provides 34.0 Kv, the later models provide 34.9 KV for a slightly brighter picture. The two types of supplies are completely interchangeable, but the newer 34.9Kv supplies are more reliable overall.

The original Marquee 9000s that were only produced for a short period used a 40Kv supply. There is a jumper wire inside the HVPS that converts the HVPS from 34 to 40Kv operation. Serious tube damage can occur if a 40Kv supply is installed in a set that needs 34Kv, but the 40Kv supplies are rare, so this is an unlikely scenario.