Samsung HLN4365W HDTV Lamp Dies

Ok... you guys always come up with some good possible answers.
I came across this DLP projector for little money. This I believe this unit
was damaged during the original shipping to the dealer as the inside is
spotless and mfrd date is 10/2004. I repaired the "ballast" transformer's
connections (on the main power supply board). It develops the required 384V
B+ that feeds the lamp ballast board and voltages measure OK. The Lamp will
fire quickly and begin to brighten for aprox 1~2 minutes and then the lamp
is extinguished and the three LEDs will blink on the front panel (indicating
"lamp problems").
The picture is fantastic during that time
The actual lamp ass'y does not "look" bad. I have worked with very similar
"Philips" 100w lamps in ELMO LCD projectors and the quartz "bulb" within the
sealed reflector is not darkened. I'm wondering if any of you know if there
might be an internal reset within the test setup menu.

I also checked the three fans for proper operation. (although the last
"tech" in it had them plugged in incorrectly (all same wire color coding
with identical plugs) but labled on bottom of PCB where fan should go.
(maybe set a alarm condition in eeprom??) Not overheating thermal switch on
lamp either.
There are 3 optocouplers on the Ballast board.
2 for signals to that board (#1power on / #2 unsure)
1 for signal from that board (changes state after lamp shuts down)
I believe it's either a bad lamp, or bad ballast as the 384v supply does not
fluctuate and the two incoming optos do not change states after the power
on command . The output opto changes state only AFTER the lamp is shut down
then the MPU flashes LEDs.

Anyone have any experiance (sp) with these DLP projectors? I'd hate to
replace the lamp only to find the Ballast is bad. Any Tips?
or got a print of the lamp circuit?

Thanks Again!
Dave McGaffney

IF the lamp was dropped, it is likely bad. This is not a quartz lamp at
all. It is a high intensity, high pressure, metal hallide lamp. The
ballast circuit might still have a fault with either the current sense or
voltage sense to the lamp, but a bad lamp will also cause the same symptom.

The choice is to try another lamp, realize you will have to keep it after
you buy it and install it, around $500 or so. Or attempt to find the
failure on the ballast without knowing if the lamp is the cause (may spend
more than $500 in opportunity labor costs just spinning your wheels). Find
out if the entire ballast board is available and try replacing it.

David

"David W. McGaffney" wrote in message
...
Samsung HLN4365W HDTV Lamp Dies

Ok... you guys always come up with some good possible answers.
I came across this DLP projector for little money. This I believe this
unit
was damaged during the original shipping to the dealer as the inside is
spotless and mfrd date is 10/2004. I repaired the "ballast" transformer's
connections (on the main power supply board). It develops the required
384V
B+ that feeds the lamp ballast board and voltages measure OK. The Lamp
will
fire quickly and begin to brighten for aprox 1~2 minutes and then the lamp
is extinguished and the three LEDs will blink on the front panel
(indicating
"lamp problems").
The picture is fantastic during that time
The actual lamp ass'y does not "look" bad. I have worked with very similar
"Philips" 100w lamps in ELMO LCD projectors and the quartz "bulb" within
the
sealed reflector is not darkened. I'm wondering if any of you know if
there
might be an internal reset within the test setup menu.

I also checked the three fans for proper operation. (although the last
"tech" in it had them plugged in incorrectly (all same wire color coding
with identical plugs) but labled on bottom of PCB where fan should go.
(maybe set a alarm condition in eeprom??) Not overheating thermal switch
on
lamp either.
There are 3 optocouplers on the Ballast board.
2 for signals to that board (#1power on / #2 unsure)
1 for signal from that board (changes state after lamp shuts down)
I believe it's either a bad lamp, or bad ballast as the 384v supply does
not
fluctuate and the two incoming optos do not change states after the power
on command . The output opto changes state only AFTER the lamp is shut
down
then the MPU flashes LEDs.

Anyone have any experiance (sp) with these DLP projectors? I'd hate to
replace the lamp only to find the Ballast is bad. Any Tips?
or got a print of the lamp circuit?

Thanks Again!
Dave McGaffney

Change both the lamp and ballast. Be advised, the lamp and ballast must
match, I.E. if your set had the Toshiba lamp then you must get that
appropiate ballast, again if it used the Phillips lamp: Ditto. We normally
change them as a matched pair, as recommended by Samsung.
"David" wrote in message
...
IF the lamp was dropped, it is likely bad. This is not a quartz lamp at
all. It is a high intensity, high pressure, metal hallide lamp. The
ballast circuit might still have a fault with either the current sense or
voltage sense to the lamp, but a bad lamp will also cause the same
symptom.

The choice is to try another lamp, realize you will have to keep it after
you buy it and install it, around $500 or so. Or attempt to find the
failure on the ballast without knowing if the lamp is the cause (may spend
more than $500 in opportunity labor costs just spinning your wheels).
Find
out if the entire ballast board is available and try replacing it.

David

"David W. McGaffney" wrote in message
...
Samsung HLN4365W HDTV Lamp Dies

Ok... you guys always come up with some good possible answers.
I came across this DLP projector for little money. This I believe this
unit
was damaged during the original shipping to the dealer as the inside is
spotless and mfrd date is 10/2004. I repaired the "ballast" transformer's
connections (on the main power supply board). It develops the required
384V
B+ that feeds the lamp ballast board and voltages measure OK. The Lamp
will
fire quickly and begin to brighten for aprox 1~2 minutes and then the
lamp
is extinguished and the three LEDs will blink on the front panel
(indicating
"lamp problems").
The picture is fantastic during that time
The actual lamp ass'y does not "look" bad. I have worked with very
similar
"Philips" 100w lamps in ELMO LCD projectors and the quartz "bulb" within
the
sealed reflector is not darkened. I'm wondering if any of you know if
there
might be an internal reset within the test setup menu.

I also checked the three fans for proper operation. (although the last
"tech" in it had them plugged in incorrectly (all same wire color coding
with identical plugs) but labled on bottom of PCB where fan should go.
(maybe set a alarm condition in eeprom??) Not overheating thermal switch
on
lamp either.
There are 3 optocouplers on the Ballast board.
2 for signals to that board (#1power on / #2 unsure)
1 for signal from that board (changes state after lamp shuts down)
I believe it's either a bad lamp, or bad ballast as the 384v supply does
not
fluctuate and the two incoming optos do not change states after the
power
on command . The output opto changes state only AFTER the lamp is shut
down
then the MPU flashes LEDs.

Anyone have any experiance (sp) with these DLP projectors? I'd hate to
replace the lamp only to find the Ballast is bad. Any Tips?
or got a print of the lamp circuit?

Thanks Again!
Dave McGaffney