infocus projector caps

[mbates14]

Is anyone familiar with infocus LP420 series at all? they must have notorious bad SMD caps because, I just got a shit load of parts in, hopefully to fix the one I got. Well, since its the 13th, its my unlucky day. The board I needed, are all bad. DAMN.

Funny thing is, each controller board problems range from scrambled VGA video up to not starting the bulb at all. I even got one, that spins the color wheel up right when its powered on, and its NOT supposed to do that. supposed to be a delay, before fireup.

I tested all SMD transistors and diodes, none appear bad. I even went agains a good board, all the same readings.

Are the caps to blame? I pulled off a couple of 10uf caps, they dont show signs of major leakage, but if you look closely at the solder pads, either one, or the other, looks to be a little bit of goup.

If I squeeze it, a fair amound of brown electrolyte comes out. One of the caps was of concern, because none came out at all till a squeezed very hard. hmm.

Any ideas?

[bushytails]

If you can squeeze them by hand and electrolyte comes out, I'd say they're toasted...

it sounds like you have multiple projectors... how much would you want to sell a dead one for? there's been a few times I could have used one, but no chance in hell of my affording a working one...

--Randy

[mbates14]

they are all missing various parts. I only have 2 complete ones, and one of them is not even mine.

I use needle nose to pull them off the board, and If i squeeze it a little with the needle nose, it comes out all bubbly.

Anyway, a couple of them, i squeezed it flat, and barely got anything out. Others, it came gushing out. the ones that barely have anything are the ones closer to the bulb and fan. The other ones are in the microprocessor area.

Itll power up, fans will whirr, then the 5 second delay, (like its supposed to), the color wheel will spin up. and thats it. the bulb should start after the color wheel, but does not. so, im thinking the CPU is detecting a problem, and prevents the ballast from igniting. I dunno.

[mbates14]

Well, I recapped one board with radials, screw SMD caps. too much trouble. I used a higher temperature rating, because the heat that is enclosed in that case.

So, with a tech in canada that a friend knows, that couldnt figure out why the majority of infocus projector hes ran into, the bulb wouldnt start. Well, Ill tel you why. The EEPROM is corrupted. I reflashed the EEPROM, and boom. problem solved. I found this out, because the unit will run without it!

But the recap solved the scrambled video.

[willawake]

GREAT job fixing a projector. well done.

pics?

[kc8adu]

i have seen lots of sm caps go in things like this.
get the dick smith esr meter and stop guessing.
i have a litepro 735 iirc that had a bad cap in the psu.
caused lots of goofy stuff.
most of the time it would start normally but have racing stripes on the logo screen and fuzzy images.

[mbates14]

Well, i can normally tell when caps are goin dead. because if it were a failed component, the circuit would not halfway malfunction, or change to something else, it would just quit. never work again.

Well, at 1000lumens, and native XGA. Cant complain.

If i think its a cap, i just recap the entire thing. reason being, if one goes bad, the next to follow.


The picture on this thing is incredible. It blows the shit outta the water on my PT-L592U.

How am I supposed to get one? with a credit card/bank card that I dont have? hmm.

[bushytails]

http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1 <== I'm tempted to bid on that... what do you think? asked the seller about the symptoms, got "The unit sounds like it is cycling or reseting."

--Randy
(and if I see anyone here outbid me...)

[arneson]

Re: infocus projector caps

I see this is an inactive thread but I'll add this anyway.

I got into the Infocus projectors last month.
Got five of them on Ebay cheap, as is.
1 works, low lumens, big old technology
1 dead, power supply out,badcaps? hmm
1 really strange bulb, dead, also big unit
2 LP 735 , these both work, very bright and clear, but had to add a bulb turn on switch to them.
This takes the place of the bulb control circuit.