InFocus LP425 won't light.

[pentium]

Re: InFocus LP425 won't light.

I push any button and the light remains orange.

[Krankshaft]

Re: InFocus LP425 won't light.

It sounds like either there is a probem on the mainboard and its not sending the power good signal to fire the lamp or the ballast board is shot and can't fire the lamp.

To isolate on what board your problem is the Infocus service manual would be required. They are very concise and tell you what pins to measure for to make sure that the mainboard isn't the culprit.

If the mainboards shot so is the unit but the ballast board can be repaired.

[pentium]

Re: InFocus LP425 won't light.

...and I don't have access to the service manual.

[Krankshaft]

Re: InFocus LP425 won't light.

Here is a site that sells it if you think its worth it.

http://www.service-manual.net/ashop/...ue.php?cat=172

[pentium]

Re: InFocus LP425 won't light.

Here is a site that sells it if you think its worth it.

http://www.service-manual.net/ashop/...ue.php?cat=172

I'll look into it.
I did get this projector for free after all.

[toounknown]

Re: InFocus LP425 won't light.

I have seen this problem many times. It is a bad HV switch (spark gap switch) on the HV daughterboard. Its a white ceramic 2 terminal device just under/beside the HV block.

These trigger around 2500V-3000V and are difficult to find at that value. The capacitors charge to the voltage, then the gap conducts once the voltage reaches the switch value and creates an arc through the switch and through the bulb igniting it.

If you can get a hold of 800v ones, and string 3 in series, that will get you there, or you can make your own. I used terminals from two old spark plugs and gapped them at 0.9 mm and this works fine for me. You will have an exposed spark, but that should be ok (unless you are in a flamable environment). Be careful with the gap. The larger it is, the higher voltage it will trigger at. I'm not sure if there is another type of limiter in this circuit, but you could burst the bulb if the gap/voltage is too big/high. Also, there is not a lot of room there and be careful, if the leads on the spark gap switch get close to anything else, it may arc where you don't want it to arc and fry something else in unit...This seems to be a problem with the LP400, LP420, LP425 and LP435 units. The newer Z versions don't seem to be as prone to this.