Dell 1800MP projector

[Ken1]

Hi, Yes, I do have the owners manual and the fault indicator descriptions that I posted came from that manual. I reassembled it and ran it without the enclosure, but it still shuts down just as quickly. The fans push air through the areas that need cooling. The projector is not mine, it belongs to the local volunteer fire department and they purchased it new 15 months ago and 18 hours is all use they gave it and I am the first one to open it up. I tried operating it without the bulb and the unit recognized right away that the bulb was missing and displayed an amber warning light. After the same 2 minutes it shut down.

[sofaspud]

It wasn't entirely clear to me how you tested the power supply. If you haven't
done so, consider disconnecting the power supply from the unit and powering it
up using an external load, e.g. power resistors, light bulbs, etc. I'm supposing that
the ps could be faulting out before a signal is received by the indicator LEDs. At
the least, you'll have the location of the malfunction narrowed down somewhat.

[Ken1]

Hi, I simply used a DMM to measure the outputs of the power supply. I tried to operate the power supply by itself without a load. It won't put out anything. Possibly it's like a computer power supply that has to be switched on externally somehow in order to function.

[Bigglez]

For example my cable modem quit last week because I turned on an external HDD it was sitting on which made it too hot to work. After resetting the modem several times with no success I put the clues together and I moved it, then it came back up a minute later.

My limited experience with ADSL modems is that they run way
too hot for simple convection cooling. Any air blockage would trip it.

In a related frustration I called for DSL tech support last week,
and go the familiar run around with Indian techs ("Hello,
my name is Sandeepkumarian, but you may call me "Ricky"...).

I had to insist I speak to his supervisor. "Ricky" was trained to
have me measure the distance form the ADSL box to my monitor,
because there may be "electrical interference". No amount of
pleading from me would convince him that the boxes haven't been
moved for over four years now. (It turns out that Covad, the local
ADSL sub-con, upgraded the CO's DSLAM and my ADSL modem
was in bridge mode instead of PPPoE, but that's a longer and less
interesting story).

Looks like I've hi-jacked this thread...

[haklesup]

I tried operating it without the bulb and the unit recognized right away that the bulb was missing and displayed an amber warning light. After the same 2 minutes it shut down.

Well, that tends to eliminate heat as the primary cause. The PS is a good next guess. Can it be disconnected from the circuit and tested unloaded or is it integrated on the same PCB.

Will it stay on long enough in standby mode to accept new firmware?

When you say it shuts down, do you mean all the way down no signs of power or it reverts to standby mode?

Factory repair may still cost less than replacement.

[Bigglez]

Hi, I simply used a DMM to measure the outputs of the power supply. I tried to operate the power supply by itself without a load. It won't put out anything. Possibly it's like a computer power supply that has to be switched on externally somehow in order to function.

Take care doing these experiments, unless you have a
disposable DMM...

As the lamp does not have a filament as I first thought,
it must be a discharge type. These have "negative resistance"
once struck, but require much higher voltage to strike.

The power supply for these has to kick the voltage up
for a short time (usecs), but long enough to kill your
DMM!

Once the lamp draws current the power supply acts as
"ballast resistor" to regulate the current through the lamp,
even as the lamp heats up and also as it ages.

Lamps that don't strike will raise an alarm. Lamps that
require too much voltage across for a given current
are assumed to be at their EOL (end-of-life) or are open
to air (broken seals or glass) and will be shut down for
safety. Lamps with too little voltage drop are assumed
to be shorted, and are shut down.

To simulate a load you need a power resistor equal to
the lamp's load line. The resistor can't be allowed to
heat up, as the resistance of wire goes up with temp
(positive coefficent), not down as for a gas plasma
discharge lamp.

Now your missing PSU schematic is of greater interest
to us!

[Ken1]

Hi, This projector has 4 circuit boards: the main power supply, the lamp power supply, the keypad board (which also has the fault indicator lights on it), and the main board which has all the input jacks on it and is where the brains of the projector are located. I disconnected the main power supply from everything else as I mentioned in my previous post and it doesn't power up. I assume it has some kind of connection to the main board that kickstarts it. When the projector shuts down, the main power supply shuts down completely. When I run the projector without the lamp, the faulty lamp warning light comes on immediately and after the same amount of running time, the projector shuts down again with the main power supply completely shut down and of course, no fault indicator lights lit. According to the owners manual, when the projector shuts down, the appropriate fault indicator lamp is supposed to remain lit or remain blinking (whicherver the case) to tell the operator why the projector shut down so that the operator knows what corrective action needs to be taken.

[dacflyer]

sounds like something is failing on the control board, if your loosing power to the lamp PS..
if i understood that right... are you saying that you are loosing power to the lamp PS??
sounds like it, since you get no failure indicators..
have you looked on www.servicemanuals.net for a service manual ??

[Bigglez]

I don't have another lamp on hand.
The lamp is powered from some kind of power supply on a separate board.

I've been unable to locate any info on-line. I guess that
Dell is keeping the service info off the street to avoid
liability (and lost service revenues).

The replacement lamp is street priced at over $200,
and supposed to run for 2500 hours. So, you can
expect to buy one every two years or so.

Are you planning to junk the projector? Seems like you
have few options. Perhaps only one - going back to
Dell for service.

[bobcataville]

Hello, unfortunately I too am having this problem. I am trying to take off the cover (top) so that I can try cleaning the dust off like someone mentioned. I am having an issue with it though. I have all the screws and the lamp taken out, but the rear part of the cover does not want to come loose. I have an issue with prying expensive plastic so it's just sitting there.

Is there something special I'm supposed to do? The lock hole on the back doesn't seem to do anything either. I know the lamp only has 750 or so hours on it so there's should be plenty of life left.

Any help would be greatly appreciated.

Thanks

[rjjacobs]

My Dell 1800mp has also failed after 2 years - it refuses to turn on - with the bulb light flashing irregularly, sometimes every 1/2 second, or then slower, which is a symptom which the manual does not describe, of course.

Folks, it sounds like we all have the same problem? If it is a hardware issue, as indicated above, what is the hardware that has failed? - power supply, fan - ? And I too am unable to get the case open fully. With all screws out the cover is stuck in the middle at the back, and I also don't want to crack it in trying to get it open. I've only used this unit about 200 hours, so it seems its refusal to turn on this way is way too premature.

We should be able to get these units fixed for much less than the $250 + parts which we're being quoted. And of course our units aren't under warranty because our Dell PC's have always worked long and faithfully so we didn't see the point for paying for an extended warranty. So why not this Dell projector? Unfortunately, the 1800mp is old technology now and you can get a new one with comparable specs for close to the repair cost + parts.

If anyone has some advice on how to open this thing up fully and replace the defective part, it would be greatly appreciated.

[bpsmanagement]

Did you ever end up replacing that cap? I discovered a 3300uf 10v cap that was slightly buldging on my PSU. It's a RLS; which are crap. I replaced it with one I ripped off a old dell 2600 Server PSU and it didn't change anything. Same problem. I may have damaged it removing it though.. I'm going to try and source one locally tomorrow and see what I can do. I'll let you guys know if I find a fix.

[ddwalker1]

Ok. I'm experiencing the same issue with the blinking amber light when I attempt to turn the projector on. I was able to remove the top cover, however, it would appear that I need to remove the bottom cover??? I can't seem to tell how to get at the component side of any of the boards. Any help would be appreciated.

p.s. www.newark.com is a fantasic place to get all kinds of electronic items. For 39 cents i was able to locate a replacement capacitor to resolve an issue with a 19 inch lcd monitor that was given to me. yeah!

I look forward to all your replies.

Thanking you in adance.

[Edd]

Sir Ken. . . . . .
Now, you hear Real Estate people say . . . Location . . . Location . . . Location

However, in your current situation now being experienced on your DELL Projo . . . you should be equally thinking along the same repetitions,
but that would instead be:
Power supply . . . power supply . . .POWER SUPPLY . . . .



Be sure and check all units for excess ESR / low capacitance . . . but particularly that 3300ufd unit

73's de Edd

[ddwalker1]

Any info on how to get to the power supply without damaging the unit? I can't seem to discover how to get to the component side of any of the boards within the projector. I opened that top of the projector, but it' looks as though I'm looking at the metal side of the power supply. Do i need to pull the BOTTOM of the projector off? if so, any words of wisdom for doing it in such a way so as not to damage the surrounding plastics?

thanks.