Dell 1800MP projector

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Ken1
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Dell 1800MP projector

Post by Ken1 » Sat Feb 14, 2009 5:36 pm

Hi, I have a Dell model 1800MP projector that works for 2 minutes or so then shuts down. I have to unplug it and wait for at least a couple of minutes before plugging it in again in order to be able to turn it back on again. It shuts down again after about 2 minutes of operation. The bulb works fine when it's on and no indicators light up or blink after it shuts down. Is it worth digging into the unit to try to fix it?

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MicroRem
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Re: Dell 1800MP projector

Post by MicroRem » Sat Feb 14, 2009 7:31 pm

I would look at heat issues, are all the fans working? Are the airways clean and unobstructed? If it was mine, I would "disassemble gently" to locate the problem. If you feel you are getting in too far, re-assemble and re- evaluate. Sure sounds like an over temp problem to me.

best

Tom

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dacflyer
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Re: Dell 1800MP projector

Post by dacflyer » Sun Feb 15, 2009 3:52 pm

some projectors have a EOL (end of life ) timer for the lamp. the lamp might still work, but the timer will cause the projector to shut down, do you know how many hrs are on the lamp ?
there should be a way to reset the timer, but do check for heat issues, make sure the fan(s) functions also.
the reason for the EOL timer is to prevent the lamp from getting to old and possibly shattering, and also to maintain color quality, if the lamp gets too old, the color might suffer, from the lamp darkening.
we had a projector with sucha problem before, the lamp appeared and looked normal, but the timer timed out. so we reset the timer, until we got in a new lamp
good luck,

Ken1
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Re: Dell 1800MP projector

Post by Ken1 » Sun Feb 15, 2009 4:27 pm

Hi, The lamp has 18 hours on it according to the OSD in the lamp menu. It's very easy to reset the hour meter.

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Re: Dell 1800MP projector

Post by Bigglez » Sun Feb 15, 2009 6:20 pm

Ken1 wrote:Hi, The lamp has 18 hours on it according to the OSD in the lamp menu. It's very easy to reset the hour meter.
Wow, is this a new projector?

Was this a new lamp, or just 18 hours
since the last lamp timer reset?

Did changing the lamp hour data (by reset) help the
original problem of the lamp cycling on and off?

Was there any dirt or debris in the fan(s)? Are they
running now?

Ken1
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Re: Dell 1800MP projector

Post by Ken1 » Mon Feb 16, 2009 5:33 am

Hi, This projector is new for all intents and purposes. Unfortunately it's off warranty now. I took it apart and it's immaculately clean inside; not a speck of dust anywhere. I haven't reset the timer yet however both fans are working perfectly. The lamp has never been replaced.

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Re: Dell 1800MP projector

Post by Bigglez » Mon Feb 16, 2009 7:37 am

Ken1 wrote:Hi, This projector is new for all intents and purposes. Unfortunately it's off warranty now. I took it apart and it's immaculately clean inside; not a speck of dust anywhere. I haven't reset the timer yet however both fans are working perfectly. The lamp has never been replaced.
So the lamp problem continues?

We have eliminated lamp fatigue, lamps timer
over run, dirt, dust, fan trouble, and debris.

Can you determine what powers the lamp?
(Regulator, controller, or bulk power supply perhaps).

Do you have a second lamp to try? As simple as
a filament lamp may be, it is possible for an open
circuit to show up at elevated (normal operation)
temps.

Ken1
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Re: Dell 1800MP projector

Post by Ken1 » Mon Feb 16, 2009 1:45 pm

Hi, I don't have another lamp on hand.
The lamp is powered from some kind of power supply on a separate board.
The projector has a fault detection system which is supposed to light up either one of 2 led's when a problem occurs. There is a temperature warning led that lights steady orange when the projector or the lamp or the lamp driver overheats. If the temperature led blinks orange, one of the fans has failed. The other led is a lamp warning. If it lights steady orange, the lamp has failed and needs to be replaced. If it blinks orange, the lamp driver has failed and the projector shuts down. The funny thing is neither of these led's blink or light steady at any time either before or after the projector shuts down so I am at a loss as to why it keeps shutting down.

Bigglez
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Re: Dell 1800MP projector

Post by Bigglez » Mon Feb 16, 2009 6:24 pm

Ken1 wrote:The lamp is powered from some kind of power supply on a separate board.
...
The projector has a fault detection system which is supposed to light up either one of 2 led's when a problem occurs.
...
The funny thing is neither of these led's blink or light steady at any time either before or after the projector shuts down so I am at a loss as to why it keeps shutting down.
So the LEDs are not on the Lamp driver board?
There must be some other link between the separate boards.

Perhaps you can use a DMM to measure the lamp voltage
(at the lamp)? Better yet a scope to determine if the lamp
is DC operated or by PWM.

It is possible that the lamp driver has its own local fault detector
(which may be the circuitry inside one or more ICs in its design).
If it shuts down for a local reason the lamp failure may not be
reported to the other board(s).

We're into pure speculation. Any chance of finding a schematic
from the manufacturer or on-line somewhere?

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dacflyer
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Re: Dell 1800MP projector

Post by dacflyer » Tue Feb 17, 2009 3:34 am

bigglez said....... As simple as
a filament lamp may be, it is possible for an open
circuit to show up at elevated (normal operation)
temps.

these projectors do not use a filiment lamp, its a HID/xenon type lamp. the power supply is a type of switching power ballast.
heres an idea.. think it might be possible that the PS might have a bad solider joint ?

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Re: Dell 1800MP projector

Post by Bigglez » Tue Feb 17, 2009 8:40 am

dacflyer wrote: these projectors do not use a filiment lamp, its a HID/xenon type lamp. the power supply is a type of switching power ballast.
Kewl! Looking forward to reviewing that schematic!

Ken1
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Re: Dell 1800MP projector

Post by Ken1 » Thu Feb 19, 2009 2:26 pm

Hi, Unfortunately I am unable to find a schematic. All outputs from the power supply are dead when the unit shuts down. I checked the power supply out thoroughly visually and tested everything but cannot find anything wrong. I am giving up on this one. Thanks everyone for your advice!

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Bob Scott
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Re: Dell 1800MP projector

Post by Bob Scott » Thu Feb 19, 2009 4:40 pm

I suppose you already have an owners' manual. If not, you can download some information here:

http://support.dell.com/support/edocs/s ... umentation

I don't see a service manual, but the user manual has a section on troubleshooting, and a way to contact Dell support.
-=VA7KOR=- My solar system includes Pluto.

Bigglez
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Re: Dell 1800MP projector

Post by Bigglez » Thu Feb 19, 2009 4:44 pm

Ken1 wrote:Hi, Unfortunately I am unable to find a schematic. All outputs from the power supply are dead when the unit shuts down. I checked the power supply out thoroughly visually and tested everything but cannot find anything wrong. I am giving up on this one. Thanks everyone for your advice!
Pity. It would have been very interesting to know if the bulb
caused the problem, or the bulb's power supply was to blame.
Perhaps that power supply is working correctly and stopping
an unsafe or unuseable condition ?

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haklesup
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Re: Dell 1800MP projector

Post by haklesup » Fri Feb 20, 2009 4:23 am

and a way to contact Dell support
I'd definately give them a call. While they will probably end up telling you its not a user servicable situation they may walk you through some debug procedures and confirm or deny some of your assumptions about the warning lights. You may end up with that all important clue.

Try repluggung the lamp module and look for the location of the temp sensor. It could be that the sensor is not working at all rather than signalling a hot condition.

8 hours could mean someone else resetted it already trying to debug the same problem before you. Did anyone work on it or open it before you? Potentially could have been reassembled incorrectly and you wouldn't necassarily know. Are you the original owner?

It still seems like temp but instead of a detected condition, it may be an IC getting hot and quitting. 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

Try augmenting the fan with additional airflow. Maybe a vacuum cleaner to pull air through rapidly or a block of dry ice near where air is pulled in. Is it ventilated with positive or negative pressure (fan blows in or out)? If it still shuts down, maybe its not temperature.

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