I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad lamp but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the "starting" circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board to the PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the supply because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power supply (which is a custom unit).

I know from Googling that InFocus usually isn't very forthcoming with schematics - just wondering if anyone here has found a
source for same? Or, anyone ever had a similar problem and had luck fixing it?

Thanks!

Eric Law
Wilmington, MA

"EL" writes:

I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad lamp but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the "starting" circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board to the PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the supply because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power supply (which is a custom unit).

I know from Googling that InFocus usually isn't very forthcoming with schematics - just wondering if anyone here has found a
source for same? Or, anyone ever had a similar problem and had luck fixing it?

Assuming it's not totally potted, you may have to trace the circuit on the
power supply and find the bad connection or bad part. The starting circuit
probably isn't that complex.

Also, check the other inputs to the power supply.

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On Mon, 28 Feb 2005 09:35:34 -0500, "EL" wrote:

I've got an InFocus LP435z DLP projector that's driving me nuts!

I understand InFocus will not provide replacement parts or technical
support whatsoever. All units must be sent in for repair.

Alan Harriman

"EL" wrote in message
...
I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad
lamp but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the "starting"
circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board to
the PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the supply
because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power supply
(which is a custom unit).



Chances of finding a schematic are slim to none, in my experience though
you'll find the problem is either a cracked solder joint or a bad
electrolytic capacitor in the lamp ballast board.

Infocus will NEVER sell or distribute the schematics. Their service reps are
on a signed contract to not give out copies. We used to have one, and like
all the other computer type devices, we had to give it out for service, to
the Infocus service people. Their rates were reasonable in relation to the
value of the unit. We later on upgraded it, to the Sony unit. Even with the
Sony unit, it still has to go back to Sony when it goes defective.

--

Jerry G.
======


"EL" wrote in message
...
I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad lamp
but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the "starting"
circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board to the
PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the supply
because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power supply
(which is a custom unit).

I know from Googling that InFocus usually isn't very forthcoming with
schematics - just wondering if anyone here has found a
source for same? Or, anyone ever had a similar problem and had luck fixing
it?

Thanks!

Eric Law
Wilmington, MA

Yeah, I've already tried the "solder joint" thing - inspected every d**m one in the PS, touched-up about 50 of them (although
none really looked bad). Will definitely have to take a look at the caps.

It's a really nasty problem since it can't be reproduced on the bench. The pj is normally mounted on the ceiling
(upside-down) and will start maybe 1/3 of the time. Remove it from the ceiling and turn it right-side-up and it starts 3/4
of the time. Put it on the bench and take the covers off and it starts 100% of the time no matter how it's oriented!

Seems like a mechanical issue to me but so far I've had it completely apart twice and haven't really found anything.

Eric Law


"James Sweet" wrote in message news:BKRUd.51080$uc.44583@trnddc03...

"EL" wrote in message
...
I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad
lamp but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the "starting"
circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board to
the PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the supply
because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power supply
(which is a custom unit).



Chances of finding a schematic are slim to none, in my experience though
you'll find the problem is either a cracked solder joint or a bad
electrolytic capacitor in the lamp ballast board.

Had a Toshiba television that would not start until I flipped the board
over. Turned out to be a loose core on a switching transformer. It moved
about a centimeter and wouldn't run.

Leonard

"EL" wrote in message
...
Yeah, I've already tried the "solder joint" thing - inspected every d**m
one in the PS, touched-up about 50 of them (although
none really looked bad). Will definitely have to take a look at the caps.

It's a really nasty problem since it can't be reproduced on the bench.
The pj is normally mounted on the ceiling
(upside-down) and will start maybe 1/3 of the time. Remove it from the
ceiling and turn it right-side-up and it starts 3/4
of the time. Put it on the bench and take the covers off and it starts
100% of the time no matter how it's oriented!

Seems like a mechanical issue to me but so far I've had it completely
apart twice and haven't really found anything.

Eric Law


"James Sweet" wrote in message
news:BKRUd.51080$uc.44583@trnddc03...

"EL" wrote in message
...
I've got an InFocus LP435z DLP projector that's driving me nuts!

The lamp (HID type) intermittently fails to ignite. Sounds like a bad
lamp but it's not - the problem is it doesn't even
*try* to ignite. The unit makes a distinctive noise when the
"starting"
circuit is going and when it's in a bad mood there's
no noise. I've managed to track down the signal from the logic board
to
the PS that tells the lamp to start and hooked an
LED to it - from this I've determined that the problem lies in the
supply
because even when the lamp doesn't start the LED
lights. So what I need at this point is a schematic for the power
supply
(which is a custom unit).



Chances of finding a schematic are slim to none, in my experience though

you'll find the problem is either a cracked solder joint or a bad
electrolytic capacitor in the lamp ballast board.

"EL" wrote in message
...
Yeah, I've already tried the "solder joint" thing - inspected every d**m
one in the PS, touched-up about 50 of them (although
none really looked bad). Will definitely have to take a look at the caps.

It's a really nasty problem since it can't be reproduced on the bench.
The pj is normally mounted on the ceiling
(upside-down) and will start maybe 1/3 of the time. Remove it from the
ceiling and turn it right-side-up and it starts 3/4
of the time. Put it on the bench and take the covers off and it starts
100% of the time no matter how it's oriented!

Seems like a mechanical issue to me but so far I've had it completely
apart twice and haven't really found anything.

Eric Law


Did you ESR the caps? I fixed a fluorescent ballast that had the same
problem, it was caused by a bad capacitor in the bootstrap circuit for the
ballast IC. They had used a 160v cap to filter the B+ on a chip with an
absolute max rating of 30v.