Samsung HLS5087W rear projection TV, 50-inch, vintage 2006. This is one of
the "tabletop" rear projection models (about 14" deep) not one of the huge
particle-board cubes.

After being on for as little as 3 minutes or as long as 30 minutes it will
just turn off. No error code (no blinking LEDs) is displayed. It's like I
pressed the Power button. When I try to restart the TV it may or may not
start right away; it may take a few tries. (See startup attempt, below.)

It's not the remote--removing the remote's batteries, the problem still
happens.

The service manual lists 3 reasons for turning off:

1. Rear lamp door is opened. I checked the continuity of the rear door switch
(OK) and even bypassed the switch by soldering a jumper across the switch
terminals. No joy.

2. Temperature reaches 203 deg (F). The fans are operating normally so
there's no way this can heat up--randomly--to 203 in as little as 3 minutes.
I've blown the dust from inside so it's not that.

3. Lamp fails to turn on 4 times. This isn't the failure mode--the lamp is on
when the TV just turns off. And failure to turn on the lamp gives a failure
LED blink code, which I don't see.

An additional symptom: after turning off, when I press the Power switch I
hear the color wheel start up (it's a dull hum, constant speed) and
immediately there's an additional buzzing a slight variable pitch to it,
higher, less than 1khz(?). I don't think it's electronic like an arc or
transformer but like another motor.

What's causing this TV to turn off?

Thanks.

On Thursday, March 5, 2015 at 10:20:11 AM UTC-5, DaveC wrote:
Samsung HLS5087W rear projection TV, 50-inch, vintage 2006. This is one of
the "tabletop" rear projection models (about 14" deep) not one of the huge
particle-board cubes.

After being on for as little as 3 minutes or as long as 30 minutes it will
just turn off. No error code (no blinking LEDs) is displayed. It's like I
pressed the Power button. When I try to restart the TV it may or may not
start right away; it may take a few tries. (See startup attempt, below.)

It's not the remote--removing the remote's batteries, the problem still
happens.

The service manual lists 3 reasons for turning off:

1. Rear lamp door is opened. I checked the continuity of the rear door switch
(OK) and even bypassed the switch by soldering a jumper across the switch
terminals. No joy.

2. Temperature reaches 203 deg (F). The fans are operating normally so
there's no way this can heat up--randomly--to 203 in as little as 3 minutes.
I've blown the dust from inside so it's not that.

3. Lamp fails to turn on 4 times. This isn't the failure mode--the lamp is on
when the TV just turns off. And failure to turn on the lamp gives a failure
LED blink code, which I don't see.

An additional symptom: after turning off, when I press the Power switch I
hear the color wheel start up (it's a dull hum, constant speed) and
immediately there's an additional buzzing a slight variable pitch to it,
higher, less than 1khz(?). I don't think it's electronic like an arc or
transformer but like another motor.

What's causing this TV to turn off?

Thanks.

Shut down is a real pain in the ass. How does the picture look just before shut down? I'm not an expert but I have worked on some of theses. I don't think it's a door problem because it seems unlikely that it would take three minutes to sense this. I don't know about the other noise but I think that if it was related to the color wheel you would notice that in the picture. I would suspect something getting too hot somewhere. With the back off try a 20 inch box fan blowing into the set and see if that may increase the time before shut down. If it does after that you'll have to get a can of cold spray and hope to get lucky. Lenny

On Thursday, March 5, 2015 at 10:20:11 AM UTC-5, DaveC wrote:
Samsung HLS5087W rear projection TV, 50-inch, vintage 2006. This is one of
the "tabletop" rear projection models (about 14" deep) not one of the huge
particle-board cubes.

After being on for as little as 3 minutes or as long as 30 minutes it will
just turn off. No error code (no blinking LEDs) is displayed. It's like I
pressed the Power button. When I try to restart the TV it may or may not
start right away; it may take a few tries. (See startup attempt, below.)

It's not the remote--removing the remote's batteries, the problem still
happens.

The service manual lists 3 reasons for turning off:

1. Rear lamp door is opened. I checked the continuity of the rear door switch
(OK) and even bypassed the switch by soldering a jumper across the switch
terminals. No joy.

2. Temperature reaches 203 deg (F). The fans are operating normally so
there's no way this can heat up--randomly--to 203 in as little as 3 minutes.
I've blown the dust from inside so it's not that.

3. Lamp fails to turn on 4 times. This isn't the failure mode--the lamp is on
when the TV just turns off. And failure to turn on the lamp gives a failure
LED blink code, which I don't see.

An additional symptom: after turning off, when I press the Power switch I
hear the color wheel start up (it's a dull hum, constant speed) and
immediately there's an additional buzzing a slight variable pitch to it,
higher, less than 1khz(?). I don't think it's electronic like an arc or
transformer but like another motor.

What's causing this TV to turn off?

Thanks.

It kind of sounds like a bad lamp. The additional buzz you hear is the ballast trying to strike the lamp. If it buzzes from a cold start and the lamp doesn't strike, it's bad. The problem with troubleshooting this problem is that if the lamp is hot, it won't restrike even if the lamp is good.

In Samsung DLP TVs, the trip voltage to shut down the ballast (and TV) is roughly 140-141 AC. If the run voltage across the lamp hits this voltage, the TV will shut down as the lamp is at the end of it's life. Note that if you leave your meter across the lamp while the ballast is attempting to strike the lamp, you'll destroy your meter, so measuring the voltage must be done carefully and only attempted when the lamp is actually lit. Don't defeat the interlock if you intend to look at the lamp running, as the UV will destroy your retinas. If the run voltage is lower than 130, your lamp is OK, and the TV could be shutting down for a different reason.

In my experience, a lamp that is bad will reach max voltage in less than 5 minutes, so the fact that yours will sometimes run to 30 minutes makes we wonder about the lamp. You defeated the interlock for a test, so my next guess if a lamp doesn't fix it is an intermittent speed sensor on the color wheel. If the sensor doesn't report rotation or is gimpy enough to prevent phase lock, the TV will shut down. Unfortunately, Samsungs of this era have no error codes to access.

"DaveC" wrote in message
...
Samsung HLS5087W rear projection TV, 50-inch, vintage 2006. This is one of
the "tabletop" rear projection models (about 14" deep) not one of the huge
particle-board cubes.

After being on for as little as 3 minutes or as long as 30 minutes it will
just turn off. No error code (no blinking LEDs) is displayed. It's like I
pressed the Power button. When I try to restart the TV it may or may not
start right away; it may take a few tries. (See startup attempt, below.)

It's not the remote--removing the remote's batteries, the problem still
happens.

The service manual lists 3 reasons for turning off:

1. Rear lamp door is opened. I checked the continuity of the rear door
switch
(OK) and even bypassed the switch by soldering a jumper across the switch
terminals. No joy.

2. Temperature reaches 203 deg (F). The fans are operating normally so
there's no way this can heat up--randomly--to 203 in as little as 3
minutes.
I've blown the dust from inside so it's not that.

3. Lamp fails to turn on 4 times. This isn't the failure mode--the lamp is
on
when the TV just turns off. And failure to turn on the lamp gives a
failure
LED blink code, which I don't see.

An additional symptom: after turning off, when I press the Power switch I
hear the color wheel start up (it's a dull hum, constant speed) and
immediately there's an additional buzzing a slight variable pitch to it,
higher, less than 1khz(?). I don't think it's electronic like an arc or
transformer but like another motor.

What's causing this TV to turn off?

Thanks.

Look for bulging capacitors. 2006 was the era of bad caps out of China. If
you have a scope look at the output of all voltage regulators for excessive
ripple.

Rick