Infocus X2 image projector , 2004

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Looks as though the shadow is a stock fault due to something coming adrift inside the light guide from the rotating colour wheel. Can't find details about the bulb though

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

The actual lamp is marked SHP58 Hg so presumably a mercury discharge lamp , so what sort of voltage and ballast to check that ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

These people will help you

Discovered what the original problem was. A rectangular tunnel between the colour wheel and the first lens, going across the airpath of a fan. Made of silvered microscope slide glass , 4 pieces forming a rectangular tunnel about 6 x 8mm but the glue at the corners failed with time or heat and the retaining spring pushes one edge in a bit. Removing the spring and the tunnel collapsed, i'm surprised the fan air didn't totally disloge them.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Before wasting my time rebuilding the 30mm long 4 x 3.7mm internal bore light tunnel I need to establish whether the bulb is actually failed or a problem with the drive .

Putting a 50 watt floodlight mercury discharge lamp across the feed, either way round produces nothing. Putting a 110V neon across the feed there is a constant orange glow but no initial flare - too short to be seen ?. Putting a 150 watt spotlight discharge lamp there, nothing. Even tried a 9 inch standard fluourescent tube in all orientations. Anyone know what the trigger voltage duration would be? I'm loathe to connect up a scope in such circumstances, how to check there is a high V trigger pulse ?

Would you expect to see black colouration in the active part of the original lamp or some other sign of problem ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I've removed the ps board. The high power, LV, side of the lamp drive looks ok, despite some varnish browning around some wide format 1K SM resistors. But on the assumed HV section, the inverter size and type of hf transformer measures weird.

4 segments to the wiring , 1 thick wire and 3 fine wire all the same fine gauge. secondary coil 115 ohm primary 0.1 ohm and another coil, presumably for control/feedback, now trace cut on the pcb to confirm, connected to the primary. This measures 16.7K despite my twisting of the transformer frame/ light prodding. 1.6K is about the most I'd expect to see on such a transformer and that on the HT side. You'd never get 20,000 turns or so of this gauge wire on such a bobbin. Still a bit hidden from view as sreening/heatsinking still in place but on the far side of one of the fine coils seems to be a bit of broken copper wire sticking up, colour of copper wire and resists a needle probe in such a manner. Anyone know of a representative/generic schematic for these gas discharge drivers ?

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

No 12V is getting to the HV circuit of JRC 2901 quad comparator/transistors/inverter transformer, because the B764 pass transistor is held off by an isolated line from the video board. Taking the output of the opto isolator low by 330R the HV circuit works. Explains why the colour wheel motor is not spinning. I somehow don't expect to fault find a complex graphics board. I don't suppose anyone has any ideas? surely does not need a video feed to check the menu functions etc, not bothered connecting one so far. Surely not a chicken and egg problem?

I now know that a standard 50W floodlight mercury discharge lamp will work on this circuit as will a 9 inch fluourescent tube and more diagnostically

380V neon runs fine but nothing without the HV circuit, 110 V very bright and a low output without the HV , just the 62V power sustain voltage.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Many projectors do require a video signal before you can access the menu.

--
Tim Phipps

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I don't think that's true of most Infocus; but I don't know every model. More commonly there are simply menu functions, like keystone adjustment, that are unavailable. I usually use the menu for rough focus and initial setup.

jak

Found out why so much dust on the bulb reflector - breakdown product of the chop-strand fibre reinforcement (asbestos?) making up the high temperature plastic surround to the lamp combined with nicotine as sticky agent.

To get some more hours out of the bulb, ie defeat the counted-out lifespan of the bulb its a matter of pressing both volume switches on the switch panel for 10 seconds , so full drive resumed to the colour wheel. lamp drive and all else. Rewinding the 3 primary coils of the inverter transformer worked, so now reliable startup now the control from the video board is resumed.

Now a matter of sticking those fiddly 4 bits of light tunnel together. Will bend back the part of the spring plate that holds the one of the vertical bits of mirror in place and just rely on the top force to hold all

4 together, in its cradle, if/when the superglue fails due to the heat. That way there will be no sideways pressure to push in the side piece and so stop down the light tunnel.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on