Phillips model 50PL9126D/37 lamp problem

A buddy of mine told me about this problem with his tv, so I told him
I'd check with this group - television plays fine for awhile (didn't
say exactly how long), then the lamp failure light blinks and the set
shuts down. After sitting a bit (cool off), it will start back up and
repeat the problem. If he puts a fan blowing directly where the lamp
is located, the set will play no problem. I am going to check fan/fans
for operation and any obstructions in the area, but I wanted to know
if any techs have seen this, with this particular model. Does the fan
run continueously or is it temp controlled? Thanks in advance group.

 

[Meat Plow]

On Thu, 1 Jan 2009 01:27:53 -0800 (PST), stokesbr@cox.netwrote:

A buddy of mine told me about this problem with his tv, so I told him
I'd check with this group - television plays fine for awhile (didn't
say exactly how long), then the lamp failure light blinks and the set
shuts down. After sitting a bit (cool off), it will start back up and
repeat the problem. If he puts a fan blowing directly where the lamp
is located, the set will play no problem. I am going to check fan/fans
for operation and any obstructions in the area, but I wanted to know
if any techs have seen this, with this particular model. Does the fan
run continueously or is it temp controlled? Thanks in advance group.

Since the lamp runs at its maximum all the time it's safe to bet that
the fan runs at its maximum all the time. Check the ventilation path
for obstructions. Also see if you are blowing air with the extra fan
on the lamp ballast. Not sure if a problematic ballast would display
as a lamp failure though. How many hours on the lamp? If it's getting
old (2000 + hours) that may also be a reason for this problem.

 

On Jan 1, 1:18 pm, Meat Plow <m...@petitmorte.net> wrote:

On Thu, 1 Jan 2009 01:27:53 -0800 (PST), stoke...@cox.netwrote:

A buddy of mine told me about this problem with his tv, so I told him
I'd check with this group - television plays fine for awhile (didn't
say exactly how long), then the lamp failure light blinks and the set
shuts down. After sitting a bit (cool off), it will start back up and
repeat the problem. If he puts a fan blowing directly where the lamp
is located, the set will play no problem. I am going to check fan/fans
for operation and any obstructions in the area, but I wanted to know
if any techs have seen this, with this particular model. Does the fan
run continueously or is it temp controlled? Thanks in advance group.

Since the lamp runs at its maximum all the time it's safe to bet that
the fan runs at its maximum all the time. Check the ventilation path
for obstructions.  Also see if you are blowing air with the extra fan
on the lamp ballast. Not sure if a problematic ballast would display
as a lamp failure though. How many hours on the lamp? If it's getting
old (2000 + hours) that may also be a reason for this problem.

I suspected the lamp could be going faulty, but I haven't been able to
put together the fact that the temperature indicator light doesn't
show when it shuts down, but keeping the area cool with a fan keeps it
running. I will try to thermally cycle the ballast to see if I can
repeat the problem, if I can access it without having to tear half the
set apart. A schematic would be helpful, and I'll see if I can find
one. Until then, thanks for the response, and I'll update the progress.

 

[Meat Plow]

On Thu, 1 Jan 2009 13:03:44 -0800 (PST), stokesbr@cox.netwrote:

On Jan 1, 1:18?pm, Meat Plow <m...@petitmorte.net> wrote:
On Thu, 1 Jan 2009 01:27:53 -0800 (PST), stoke...@cox.netwrote:

A buddy of mine told me about this problem with his tv, so I told him
I'd check with this group - television plays fine for awhile (didn't
say exactly how long), then the lamp failure light blinks and the set
shuts down. After sitting a bit (cool off), it will start back up and
repeat the problem. If he puts a fan blowing directly where the lamp
is located, the set will play no problem. I am going to check fan/fans
for operation and any obstructions in the area, but I wanted to know
if any techs have seen this, with this particular model. Does the fan
run continueously or is it temp controlled? Thanks in advance group.

Since the lamp runs at its maximum all the time it's safe to bet that
the fan runs at its maximum all the time. Check the ventilation path
for obstructions. ?Also see if you are blowing air with the extra fan
on the lamp ballast. Not sure if a problematic ballast would display
as a lamp failure though. How many hours on the lamp? If it's getting
old (2000 + hours) that may also be a reason for this problem.

I suspected the lamp could be going faulty, but I haven't been able to
put together the fact that the temperature indicator light doesn't
show when it shuts down,

You mentioned above that the lamp failure light blinks then the
set shuts down.

but keeping the area cool with a fan keeps it
running. I will try to thermally cycle the ballast to see if I can
repeat the problem, if I can access it without having to tear half the
set apart. A schematic would be helpful, and I'll see if I can find
one. Until then, thanks for the response, and I'll update the progress.

The ballast should be easy to spot and it's usually fairly close to
the lamp structure. You'd need to know how much current the ballast
draws after the lamp is lit. The lamp runs a few thousand volts at
startup then backs down to around 60. However the current draw is as
great or greater when lit and stablized. You might need a service
manual to track this one down unless you get lucky and shotgun the
lamp and ballast which is a huge expense that i wouldn't recommend.