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On Sun, 26 May 2013 04:25:52 -0700, Michael Karas
wrote:

[This followup was posted to sci.electronics.repair and a copy was sent
to the cited author.]

In article ,
says...

On Fri, 24 May 2013 06:08:53 -0700, Michael Karas
wrote:

[This followup was posted to sci.electronics.repair and a copy was sent
to the cited author.]


I am repairing an LCD monitor that has the very common turn on
problems.
This is an I-INC IF281D unit with model number showing as HSD1040. I am
in the process of replacing all the capacitors on the PhiHong power
supply board (model PSM217-404-H-R) and have noticed that one
transistor
looks like it got excessively hot. I would like to replace that
transistor but have to first ID the part number. To this end I have two
questions...

Does anyone know where it may be possible to get a schematic for the
PSM217-404-H-R power supply board?

The overheated transistor is an SMT device with a code DFRG marked on
top. Any idea as to what that part number may be?
Google 'marking code DFRG' and see if anything makes sense. Also, SMT
is a very generic term. If we knew the specific package, it would
help us help you.

Another resource, especially whre power supplies for LCD monitors are
concerned is www,badcaps.net/forum. Pictures help.

PlainBill

Here is a link to a picture of the transistor in question.

https://docs.google.com/file/d/0BxTb...EMTlDaW8/edit?
usp=sharing

(Note link above may be split by a line break).

The transistor package body is 2.5mm x 4mm. Lead spacing is 1.5mm.
According to a document I checked here at the next link this package is
a SOT-89 (also apparently referred to as a T0-243 or an SC-62).

http://www.nxp.com/documents/outline.../sot089_po.pdf
Excellent pictures, thanks. I believe the actual marking code is DF;
the R indicates the gain and the G is a prouction lot or date code.

My favorite source for arcane marking info: http://www.s-manuals.com

Which leads to: http://www.s-manuals.com/smd/df

And the datasheet: (watych out for line breaks)
http://www.s-manuals.com/pdf/datashe...d1898_rohm.pdf
IF you are in the USA, they are available from Digi-Key
(ww.digikey.com) for $.53 each. (Choose USPS First Class Mail for
lowest shipping cost.)

As a general rule, I dissaprove of replacing parts because they 'look
bad'. A few minutes making measurements with a DVM can give a wealth
of information.

PlainBill



Based on years of experience at component level, +1 on that. Unless there is
a very good reason, I've never been an advocate of 'shotgunning' for the
hell of it ...

Arfa