Dell E173fpf - No led coming on

[quattro alex]

Re: Dell E173fpf - No led coming on

Thank you for confirming this. I am having problems locating a match for the original srf10-10 component. Can anyone advise of a stockist? Preferably in the uk. Many thanks

[selldoor]

Re: Dell E173fpf - No led coming on

Thank you for confirming this. I am having problems locating a match for the original srf10-10 component. Can anyone advise of a stockist? Preferably in the uk. Many thanks

You need to be specific about what you are asking for. I believe the SRF10-10
has only 2 legs whereas the SRF10-10CT has 3? Please quote full part number
or a picture if readable.

[quattro alex]

Re: Dell E173fpf - No led coming on

This is the pic of the original component and the wrong one on the left hand side. I cannot see the CT designation anywhere.

[Jasgriff]

Re: Dell E173fpf - No led coming on

Is this one a better replacement?

http://uk.farnell.com/ixys-semicondu...cfp/dp/1572488

Here is the original

http://www.datasheetarchive.com/SRF10-10-datasheet.html

[budm]

Re: Dell E173fpf - No led coming on

Hi JASGRIFF, unfortunately the one from FARNELL is a single DIODE per spec sheet (the picture on the web page is not what the part is), not dual diode with common Cathode at center pin as the original.
Full number is SRF10-10-CT-LFR: CT is for center pin for dual diode type.

[quattro alex]

Re: Dell E173fpf - No led coming on

Is the spec of this part rare? as I am struggling for search results for resellers.

[budm]

Re: Dell E173fpf - No led coming on

http://www.mouser.com/ProductDetail/...F%2f1%2fBV8%3d

100V, 10A or more, case ITO-220AB, COMMON CATHODE, SHOTTKY.

[selldoor]

Re: Dell E173fpf - No led coming on

St also make one STPS10H100CFP is 5amps per leg
or STPS20H100CFP is 10 amps per leg - digikey or mouser.

[Jasgriff]

Re: Dell E173fpf - No led coming on

Hi JASGRIFF, unfortunately the one from FARNELL is a single DIODE per spec sheet (the picture on the web page is not what the part is), not dual diode with common Cathode at center pin as the original.
Full number is SRF10-10-CT-LFR: CT is for center pin for dual diode type.

Thought that part was to easy to find

[quattro alex]

Re: Dell E173fpf - No led coming on

Thanks for putting me on the right track. Now I know what I am looking for I'll get that component in my next order.. but before that I'll be creating a new thread and investigating my old Phillips.

[quattro alex]

Re: Dell E173fpf - No led coming on

Ok I've replaced it with Selldoor's recommendation a STPS20H100CFP. Connected the board to the mains and the power LED was lit. Great I thought so I disconnected the power and reassembled the monitor - switched it on and the LED was not lit.

That was yesterday so this afternoon I tried and the LED power light came on for about 3-4 seconds and then went out again.

I have dissembled and tested:

C857 - startup cap - ~6vdc
C854 - large cap - steady 340v dc

The transformer is quiet, so I am not sure what to do next?

[retiredcaps]

Re: Dell E173fpf - No led coming on

I have dissembled and tested:

C857 - startup cap - ~6vdc
C854 - large cap - steady 340v dc

1) Get a helper. Plug lcd into power bar with a on/off switch.

2) Put your red probe on the SMPS IC VCC pin, black probe on the SMPS IC GND pin. Leave it there the entire time. Hold the probes steady and do not slip.

3) Tell your helper to power on power bar switch.

4) Watch the multimeter and note the readings for the next 15 seconds. You want to see the reading as soon as the power bar switch is turned on.

5) Report your findings if the voltage dropped, held steady, peaked, etc.

6) Get helper to turn off power bar switch.

7) Repeat the exact same tests, but now measure startup cap C857.

8) Do all the above 2 or 3 times to verify results.

[quattro alex]

Re: Dell E173fpf - No led coming on

OK with a little help from the wife I have the following results albeit they seem a bit strange....

1st test:
SMPS:6v initially, then rising to 13v then fluctuating between 13v and 14.2v during this time led light is flashing green constantly.
C857: fluctuating between 12.9 and 14.2v

2nd test:
SMPS 6v initially then rising to 9v and staying there - no led light
C857: Steady around 8.5v

3rd test:
SMPS voltage rose quickly to 15.5v then increased to 16.2v, led flashing green at this point, then I heard a noise like a gas escaping - at this point I removed the test leads.

Having completed these tests I turned the power off and found that the led would keep flashing green for around 1-2 mins after. During this time I took measurements at the smps and found fluctuating voltage between 12v-15.5v

Does this give any further clues as to what is going on?

[retiredcaps]

Re: Dell E173fpf - No led coming on

Does this give any further clues as to what is going on?

1) It seems like you might have a dodgy solder point somewhere? Does pressing down on the board with a wooden stick have any affect on the power LED?

2) Measure the voltage regulators: U801, U802, and U851.

Put your black probe on a ground screw. Leave it there the entire time. This is your ground.

3) Put your red probe on each of the pins including the "cut" pin, but ignore the "fat" tab. The fat tab is "up" or "north". Number the pins left to right.

4) You should have 3 readings per regulator (5 for U851).

5) Report them like so along with the part number (include all lines on the IC) of the IC.

U100
AS1117-33
pin 1 = 0.0
pin 2 = 3.3
pin 3 = 5.0