LJ44-00092C

[eltron]

Hello guys,
Please i need your assistance with this board [Samsung, LJ44-00092C].
There is a voltage shortage at VG out =15volt and D5v out =5.2v. The
current voltage i have here coming out from VG=15volt is 13volt and
D5v=5.2volt is 3volt. Every other dc outlets are outputing perfectly
fine. I have changed the voltage regulators 7815 for 15volt and
Lm2576t which is responsible for 5volt but yet i still get the same
13volt and 3volt out. Can someone tell me what exactly is responsible
for this shortage? i'll really welcome your contributions.
Thanks guys hope to hear from you sooner.
eltron.

 

[Eike Lantzsch, ZP6CGE]

eltron wrote:

Hello guys,
Please i need your assistance with this board [Samsung, LJ44-00092C].
There is a voltage shortage at VG out =15volt and D5v out =5.2v. The
current voltage i have here coming out from VG=15volt is 13volt and
D5v=5.2volt is 3volt. Every other dc outlets are outputing perfectly
fine. I have changed the voltage regulators 7815 for 15volt and
Lm2576t which is responsible for 5volt but yet i still get the same
13volt and 3volt out. Can someone tell me what exactly is responsible
for this shortage? i'll really welcome your contributions.
Thanks guys hope to hear from you sooner.
eltron.

I don't know the board.
What is the input voltage for the regulators? I guess it's about 13V and 3V -
so no regulation. Is it a switched PS? If switched is the chopper a
push-pull arrangement or single ended? Is the transformer hot? Is there
extreme ripple on the input voltages of the regulators? Is there a
thermistor in series with the line input? Are both regulators on the
same rectifier or do they have their own transformer winding, rectifier
and capacitor? Last but not least: Do you operate a 230V PS on 120V?
Not enough data to suggest a solution.

Kind regards, Eike
--
"The adventures may be mad, but the adventurer must be sane."
- G. K. Chesterton (1908)

 

[Arfa Daily]

"Eike Lantzsch, ZP6CGE" <eikelan@gmx.net> wrote in message
news:slrnipesl4.plr.eikelan@ID-77364.user.individual.net...

eltron wrote:
Hello guys,
Please i need your assistance with this board [Samsung, LJ44-00092C].
There is a voltage shortage at VG out =15volt and D5v out =5.2v. The
current voltage i have here coming out from VG=15volt is 13volt and
D5v=5.2volt is 3volt. Every other dc outlets are outputing perfectly
fine. I have changed the voltage regulators 7815 for 15volt and
Lm2576t which is responsible for 5volt but yet i still get the same
13volt and 3volt out. Can someone tell me what exactly is responsible
for this shortage? i'll really welcome your contributions.
Thanks guys hope to hear from you sooner.
eltron.

I don't know the board.
What is the input voltage for the regulators? I guess it's about 13V and
3V -
so no regulation. Is it a switched PS? If switched is the chopper a
push-pull arrangement or single ended? Is the transformer hot? Is there
extreme ripple on the input voltages of the regulators? Is there a
thermistor in series with the line input? Are both regulators on the
same rectifier or do they have their own transformer winding, rectifier
and capacitor? Last but not least: Do you operate a 230V PS on 120V?
Not enough data to suggest a solution.

Kind regards, Eike

I agree that the input voltages to those regulators are probably low, and
that the most likely cause, is a bad filter cap on a (shared ?) source rail.

Arfa