Dell 3008wfp faulty power supply

[selldoor]

Re: Dell 3008wfp faulty power supply

Ok - test it again out of circuit.

[fuus]

Re: Dell 3008wfp faulty power supply

and how do I do that? Sorry for my noob-i-ness D:

[selldoor]

Re: Dell 3008wfp faulty power supply

I think this will be a double diode so if it has three legs
do the following test on one side and the middle then do it on the other pair ( middle and other side)

This test is from retiredcaps 2 sec to black guide which is interesting for anyone doing anything like this- start at post 20
https://www.badcaps.net/forum/showthread.php?t=10419


7.3) Bad Diode
-----------------

Diodes (D or ZD designation) can be bad. To test a diode in circuit,

a) put your multimeter in diode test mode
b) put your black lead on one side and the red lead on the other - record reading
c) reverse the leads - recording reading

A good diode should read 0.4V to 0.7V in one direction and 0L in the other. If you get a reading in both directions

[fuus]

Re: Dell 3008wfp faulty power supply

Do I not need to hook up some kind of current to the diode for the test to work?

[selldoor]

Re: Dell 3008wfp faulty power supply

Do I not need to hook up some kind of current to the diode for the test to work?

NO! You only ever need power on if someone asks you to test/check a voltage.

[retiredcaps]

Re: Dell 3008wfp faulty power supply

Do I not need to hook up some kind of current to the diode for the test to work?

Your multimeter when set to diode test mode provides a small current through the diode. See

http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

[phroid]

Re: Dell 3008wfp faulty power supply

Greetings,
Count me too in the success stories list: last week the display died (completely: no blue/orange led).
Found D22 died in closed circuit state, today I replaced it with a STPS60170CT and now it's back working flawlessly. It costed me about 3€ and 2 hours of work.
Thank you all for this great thread.

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Greetings,
Count me too in the success stories list: last week the display died (completely: no blue/orange led).
Found D22 died in closed circuit state, today I replaced it with a STPS60170CT and now it's back working flawlessly. It costed me about 3€ and 2 hours of work.
Thank you all for this great thread.

Excellent! Great to hear! Now if we can get fuus fixed up; I'll be able to sleep again

[fuus]

Re: Dell 3008wfp faulty power supply

SO:
Original D22 Readings:
Black Left, Red Centre: 007, Black Left, Red Right: 007
Red Left, Black Centre: 007, Red Left, Black Right: 007

Replaced D22 Readings:
Black Left, Red Centre: 1, Black Left, Red Right: 1
Red Left, Black Centre: 122, Red Left, Black Right: 1

Original D19 Readings: (potentially shorted one)
Black Left, Red Centre: 1, Black Left, Red Right: 1
Red Left, Black Centre: 052, Red Left, Black Right: 1

I applaud your commitment to helping people Lumberjack, I'm sure many people are grateful for the help!

[selldoor]

Re: Dell 3008wfp faulty power supply

You seem to have not done the test correctly?

First pair

Black Left, Red Centre:
Red Left, Black Centre:

Second pair

Black Centre, Red Right:
Red Centre, Black Right:


Where you have 1 do you mean 1 or Off Scale

[fuus]

Re: Dell 3008wfp faulty power supply

By 1 I assume it means off the scale, as it shows 1 when the probes arn't touching anything!

First pair (D22 Original (broken!))

Black Left, Red Centre:020
Red Left, Black Centre:020

Second pair

Black Centre, Red Right:030
Red Centre, Black Right:020

First pair (D22 Replacement)

Black Left, Red Centre:1
Red Left, Black Centre:150

Second pair

Black Centre, Red Right:150
Red Centre, Black Right:1

First pair (D19 (The shorted one))

Black Left, Red Centre:1
Red Left, Black Centre:070

Second pair

Black Centre, Red Right:070
Red Centre, Black Right:1

[fuus]

Re: Dell 3008wfp faulty power supply

bump!

[fuus]

Re: Dell 3008wfp faulty power supply

[[[[[RETEST]]]]]]
First pair (D22 Original (broken!))

Black Left, Red Centre:000
Red Left, Black Centre:000

Second pair

Black Centre, Red Right:000
Red Centre, Black Right:000

First pair (D22 Replacement)

Black Left, Red Centre:1
Red Left, Black Centre:115

Second pair

Black Centre, Red Right:115
Red Centre, Black Right:1

First pair (D19 (The shorted one))

Black Left, Red Centre:1
Red Left, Black Centre:045

Second pair

Black Centre, Red Right:044
Red Centre, Black Right:1

[budm]

Re: Dell 3008wfp faulty power supply

"First pair (D22 Replacement)

Black Left, Red Centre:1
Red Left, Black Centre:115

Second pair

Black Centre, Red Right:115
Red Centre, Black Right:1"

Are you using the meter in Diode testing mode or using Ohm mode?
"115" is that MOhm, KOhms, Ohm, V?

[fuus]

Re: Dell 3008wfp faulty power supply

"First pair (D22 Replacement)

Black Left, Red Centre:1
Red Left, Black Centre:115

Second pair

Black Centre, Red Right:115
Red Centre, Black Right:1"

Are you using the meter in Diode testing mode or using Ohm mode?
"115" is that MOhm, KOhms, Ohm, V?

Diode testing mode. The multimeter is a 'Blackspur DT-100'. I have no idea about Ohms for the mode sorry

[budm]

Re: Dell 3008wfp faulty power supply

When you check semiconductor device for short, use Ohm function since bad semiconductor junction will act more like low Ohm resistor, it will no longer act like Diode any more.
D22 is OK.
Check D19 in Ohm mode to see what you get, so far it looks like it has very low Vf.

[fuus]

Re: Dell 3008wfp faulty power supply

which probes on which side? and at what ohm setting? I have: 200, 2000, 20k, 200k, 2000k

on the 200 setting I got a reading of 69.9 for red left and black centre
I also got 69.9 for black centre red right!

[samuelmorris]

Re: Dell 3008wfp faulty power supply

I just want to thank the major contributors to this thread - I'm in the same predicament and have got quite a lot to go on thanks to the posts here. Have ordered a pack of STPS60170CTs (minimum order of 5 :/) and will hopefully be taking a look at it this weekend. It's quite promising how many people have fixed the issue by changing this single component.

[budm]

Re: Dell 3008wfp faulty power supply

"on the 200 setting I got a reading of 69.9 for red left and black centre
I also got 69.9 for black centre red right!"
Now do the reverse:
black left and red center
black right and red center

[fuus]

Re: Dell 3008wfp faulty power supply

both get no reading what so ever.