Dell 3008wfp faulty power supply

[fuus]

Re: Dell 3008wfp faulty power supply

If you know Chinese the listing is here: http://item.taobao.com/item.htm?id=13847687345

[selldoor]

Re: Dell 3008wfp faulty power supply

Heading google traslates as
The spot 0728D04205 0728D04028LF of 100% new the DELL 3008WFP original power board
Suggests it is new? - I have someone visiting at the weekend who speaks chinese - if the opportunity occurs I will ask them.

[fuus]

Re: Dell 3008wfp faulty power supply

Cheers selldoor! I guess if I keep my expectations low then things can only get better right?!

[chaztek]

Re: Dell 3008wfp faulty power supply

Has anyone ever been able to get a schematic of the Power supply...I had two of these monitors down at the same time (think they had been purchased at the same time) and both had the small caps in the Oscillator section go bad..one came back on after just changing the 22uf and 47 uf C11 and c19 BUT one of them i forgot to re-solder the heat sink components back on and powered up and hear this little *snap* and after looking around i found a surface mount zener had popped.(Z23). i was able to see the writing enough to determine its markings..then found another with the same markings took it out and tested its voltage and it seems to be around 35 volts....But im a bit concerned about if this is correct....the model monitor is a 3008wfpt.... any thoughts....

[chaztek]

Re: Dell 3008wfp faulty power supply

I managed to disassemble my broken 3008WFP today. Right now, I am stuck. I cannot find a way to remove the power board. It seems to be strongly glued to the metal back. Can anybody give me a hint?

@r-sherwood: I would be happy to take one of these.

I pushed a small screwdriver through one of the screw holes on the back side of the metal frame pushing against some of the metal heat sink exposed by the wide screw hole.....whats holding it is just the plastic heat material is stuck down to the heat sink..a little pressure from behind and they come off ok...

[chaztek]

Re: Dell 3008wfp faulty power supply

Hi Guys,
Today I got a Dell 3008wfp without a picture but the Blue power LED still lights up and therefore I dont think that it is power related problem. I read all the 11 pages of contribution about this thread and am happy that there were several who managed to repair their TV's. Unfortunately I did not come across anyone having my problem that is power ok (Blue LED on) but without any picture. Can anyone pls give me an indication what to chk or maybe D22 could still be the faulty component ?
Many thanks and keep up this excellent site.

C11 and c 19 on the center area just under the middle heat sink..it worked for me with the same problem..these i think are for the Oscillator section secondary supply ..so the 5 volts to the microprocessor is good but the screen wont power up.. try changing these c11 47uf 50 or 60 volts 105 degree C19 is 22 uf at 50 to 60 volts 105 degree. i fixed two of these this way....

[fuus]

Re: Dell 3008wfp faulty power supply

Replacement arrived today. One of the capacitors has been damaged in transit, trust my luck... Also looks like the diode has been replaced on this board with an identical replacement. *sigh*

[selldoor]

Re: Dell 3008wfp faulty power supply

Not brand new then!!! My chinese chappie said they can almost say what they want - no trade descriptions act and they can always argue that that is not what it says due to different dialects.
Anyway I am sure you can replace a cap? and replacing like with like may not be bad - at least you dont have to do it

[fuus]

Re: Dell 3008wfp faulty power supply

the cap has a dent in it, will it still function correctly? It has not split open!

Shall I look to replace the diode or shall I see how long this one lasts?

[selldoor]

Re: Dell 3008wfp faulty power supply

Its a catch 22 considering your soldering might be better to leave the cap but if it is damaged then if it goes really bad it could take out more components.
Again, I would try leaving the diode but I cant remember - if that goes does it damage other components? has anyone said what causes them to go bad ( Knock on from ripple from bad caps?) or are they just under spec.

What make are the caps on it?

[fuus]

Re: Dell 3008wfp faulty power supply

I have a feeling they're under spec.

All caps on the board are nichicon

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Its a catch 22 considering your soldering might be better to leave the cap but if it is damaged then if it goes really bad it could take out more components.
Again, I would try leaving the diode but I cant remember - if that goes does it damage other components? has anyone said what causes them to go bad ( Knock on from ripple from bad caps?) or are they just under spec.

What make are the caps on it?

When the D22 schottky diode goes out; it doesn't take any other components with it. You just have no power. No Led. I believe it goes out during a voltage spike because the original is rated at 120v (reverse voltage) and we are replacing them with 170v.

I have a feeling they're under spec.

All caps on the board are nichicon

The caps on that power board are excellent. 125c Nichicons. If it just has a small dent I wouldn't worry. Like you said, if its not split open or leaking. But that's your choice.

Or, you can contact the seller and tell them you want a replacement. Good luck man!

[fuus]

Re: Dell 3008wfp faulty power supply

I think it's pretty difficult to get hold of replacements from TaoBao, the agent who sold it stated pretty clearly that any damage wouldn't be claimable against...

Should I run the PSU not plugged in to anything for a while to test to see if the cap will go bang? or put in back in the monitor and run it that way?

Thanks, Fuus

[selldoor]

Re: Dell 3008wfp faulty power supply

You havent told us which cap it is? - it could be that if the boards are not all connected it would never receive any voltage. Perhaps a picture so LJ can assess the size of the dent?

Whatever you decide switch it on from a distance. I am even wondering if
wiring a 60w filament bulb instead of the mains fuse might be a good idea.

[fuus]

Re: Dell 3008wfp faulty power supply

I switched it on earlier for about 30 seconds and not much happened to be honest. The cap is a 1000uF 35V one. Pics to follow

[selldoor]

Re: Dell 3008wfp faulty power supply

I switched it on earlier for about 30 seconds and not much happened to be honest. The cap is a 1000uF 35V one. Pics to follow

Well that could be good or bad - at least it didnt

I suppose testing the voltages on the connectors would let you know if it was alive.

[fuus]

Re: Dell 3008wfp faulty power supply

on the 2000k Ohm setting on my multimeter it read 10.15 and was rising
I knew the board was live because I could hear a very high pitched cap whine

[selldoor]

Re: Dell 3008wfp faulty power supply

I dont know if it bad enough to change it out -wait and see what the others say.
Were there any traces on that corner that have been damaged - might be better to check on the old board. I suppose you could pinch the cap off that?

[fuus]

Re: Dell 3008wfp faulty power supply

the damage is miles away from damaging any traces
Pinching a cap off the old board sounds good, however I doubt my soldering skills...

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Great pictures fuus. It looks like it's been dropped. You should send those pics to TaoBao. If they don't back up their products, they are not getting my business, or hopefully anybody elses that read these threads.
I see the corner of the pcb is also chipped. Normally that would be a ground internally. But who knows what other damage may have incurred. That chinese company better compensate you, or they are not getting any of my business. Up to you mate. It shouldn't be making a whining noise either. The ones we replaced were totally silent. Contact them, and tell them all the problems. And that it has been dropped and damaged. That's totally unacceptable mate. Good luck.