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  #1  
Old 08-17-2018, 07:07 AM
Solid_State Solid_State is offline
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Lightbulb Vidikron Vision Model 40 will not power on

I was given a Vidikron Vision Model 40 HD DLP projector

The only information I have for its prior use is it was mounted on the ceiling and they were using RS232 commands to turn on/off the unit so the hard power switch was never touched.

The power LED is supposed to light orange upon receiving AC power however that does not happen the unit is totally dead.

I checked the AC line fuse and the lamp interlock switch and both check out fine (Both have continuity).

Should I check the hard off power switch?

I did not do that when I had the unit apart.

I don't think that would be bad though as it was in the on position when I got the unit and the switch feels fine.

Also the lamp look fine (as in the arc-tube is not all black it is still relativity clear). I do not know how to check the lamp other then the visual inspection that I already did

Thanks
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Old 08-17-2018, 01:59 PM
mr_rye89's Avatar
mr_rye89 mr_rye89 is offline
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I'm betting the switch mode power supply in it is dead. Anything toasted on that board?

Strangely enough I had some kind of power surge and it rek'd my Monster Power Center and killed the power supply in my JVC DLA-RS20 (LCoS) projector

I didn't have anything toasty/burned on that PSU, solderable fuses checked out ok, the big semiconductors checked out okay, as did the transformers. Hell it even has high voltage around most of the board, but NADA on the secondary/low volt outputs. I'm gonna fart around with the optoisolators tonight and see if that does anything.

TL;DR

If none of the big resistors/caps/semiconductors/fuses are toast, it might be the control/PWM circuits or the optoisolators that couple the primary and secondary sides of the circuit.

But take it with a grain of salt, I'm just barely learning about SMPS's and how to fix 'em
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Old 08-18-2018, 08:33 PM
zeno zeno is offline
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SMPS's can be a son of a bitch to deal with. A few hints.....

The FET or transistor needs a + kick to the B or G to start
things. After that the feedback ( via isolators or a winding ) hold
things down.
FETS or Xistors will almost always fail DEAD short.
Current through a low ohm E or S resistor on the output is
measured. Too much current causes shut down (SD).
Shut-down is either totally dead, lowering freq, or changing pulse
width. You can often hear it ticking or screaming.
Shorts on the secondaries such as shorted Hoz out cause SD.
Secondary rectifiers NEED to be exact replacements or else...

If you dont see any obvious problem start with the electrolytics
in the primary side. Then over to the secondary.
BTW dont forget you are dealing with two grounds. One is
the HOT primary. The other is the cold secondaries.

enuf fer now
73 Zeno
LFOD !
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  #4  
Old 08-18-2018, 11:10 PM
Solid_State Solid_State is offline
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Yeah nothing looks visibly fried and as I expected the power switch checks good so does the power cord I was using , the unit has a detachable computer style IEC power cord.

That is about it for my level of expertise as I think the SMPS failed and that is beyond my skill level to fix one of those.
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