Samsung 753DF continued

[DragonMaster]

Horiz. transistor seemed to be short, until I removed it(The diode
checker beeps when checking between pin 1 and 3 holes, with the HTrans
removed).

I now think it's the DP104C IC "power switch".
(The current might get too low, turn the switch off, recharge, turn on
.. . .)

 

[Jason D.]

Horiz. transistor seemed to be short, until I removed it(The diode
checker beeps when checking between pin 1 and 3 holes, with the HTrans
removed).

I now think it's the DP104C IC "power switch".
(The current might get too low, turn the switch off, recharge, turn on
. . .)

I have worked on all their Samsung models made since 1998 and this is
not where you're looking for. The design of this SMPS IC is so good
it will protect itself no matter how hard shorts is on outputs.

SMPS is starting fine because it did start up and shuts down which you
heard the relay click. Did LED light up then goes out?

Put that part back in and what you have to is throubleshoot the
horizontal section. Very often failure point. Usually the flyback
(this one that generates HV and has focus pots), horizontal
transistor, even CRT itself. Also a B+ regulator (using a FET for
chopping up DC through a inductor to the power input on flyback
transformer then out to the HOT's collector.

If you can't find problem, it is scrap parts. A new Samsung monitor
is roughly 150-200 for 17" flat CRT new with warrante.

Samsung WILL NOT sell parts whom is not samsung's service authorized.

Only way is identify the part via their schematic and order parts
through your friendly samsung's service authorized shop. Oh yes, the
part delivery is VERY rapid and cost of parts is medium expensive.

Cheers,

Wizard

 

[Antoine Deschênes]

Jason D. a écrit :

On 22 Jan 2005 17:21:46 -0800, [email protected] (DragonMaster)
wrote:
....



I have worked on all their Samsung models made since 1998 and this is
not where you're looking for. The design of this SMPS IC is so good
it will protect itself no matter how hard shorts is on outputs.

SMPS is starting fine because it did start up and shuts down which you
heard the relay click. Did LED light up then goes out?

No, the LED never light, except a fraction of second the first time
after being unplugged for two weeks.

Put that part back in and what you have to is throubleshoot the
horizontal section. Very often failure point. Usually the flyback
(this one that generates HV and has focus pots), horizontal
transistor, even CRT itself. Also a B+ regulator (using a FET for
chopping up DC through a inductor to the power input on flyback
transformer then out to the HOT's collector.

Can I remove the flyback and see if the LED lights? Or it's like
fluorescent transformers, that will die of there's no load?

Also, when the H transistor is removed, the traces where its pins 1 and
3 go seem shorted, the diode checker beeps.

If you can't find problem, it is scrap parts. A new Samsung monitor
is roughly 150-200 for 17" flat CRT new with warrante.

Yeah, I know, these things have 3 year warranty . . . Strangely(Not at
all) the warranty just expired.