Dell 3008wfp faulty power supply

[embalse]

Re: Dell 3008wfp faulty power supply

Hi everyone,

Like you all i seem to have the same issue with my 3008WFP, at first i thought it was an expensive paper weight until i found this thread... however after getting my hopes up for repairing the screen i discovered that the replacement part is obsolete, STPS30170CT.

My skills consist of being able to solder and that is about it, so i really don't know what i am looking for other than the part number, is anyone able to point me in the right direction of the current replacement to a STPS30170CT.

Thanks in advance.

I understand your need for guidance. With a thread as long as this there is so much information that it can become overwhelming and the presumption by those more experienced is that you have not read the entire thread when in fact if you are like me and never taken a monitor apart even reading all the threads twice left me still confused. It was only when I opened up the monitor did it start to make sense of it all.

It would be better to assume that a newbie has read the threads but still need help, after all is that why we are are all here, to help.

If you watch these video´s..

http://www.youtube.com/watch?v=89Z8-eYknmc

Then look at the pictures in post #28 that show the D22 diode that needs replacing that would be a good place to start. When you open up the monitor, those pictures and other posts in the thread will start to make sense.

The hardest part for me was getting the bezel off. The rest is straight forward until you need to remove the diode and even that is straight forward if you watch a couple of videos on how to solder/de-solder parts on the board.

Good luck.

[kbob]

Re: Dell 3008wfp faulty power supply

Thanks to everyone in the thread! I've just repaired my monitor tonight.

I managed to replace D22 without removing the heatsinks and the other diodes. I removed the two screws from the top of the heatsink (seperating the two parts) this meant I could flex some room to unbolt D22 and pull it out, heatsink inplace.

Very happy I fixed this monitor - An expensive purchase when new and something I could'nt have afforded to replace in my current circumstances.

Thanks again to everyone who posted such great instructions to this thread!

Bret

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Thanks to everyone in the thread! I've just repaired my monitor tonight.

I managed to replace D22 without removing the heatsinks and the other diodes. I removed the two screws from the top of the heatsink (seperating the two parts) this meant I could flex some room to unbolt D22 and pull it out, heatsink inplace.

Very happy I fixed this monitor - An expensive purchase when new and something I could'nt have afforded to replace in my current circumstances.

Thanks again to everyone who posted such great instructions to this thread!

Bret

Way to go! That's interesting how you managed to change it without pulling the heatsink. I did also, but in a different manner. What I did was pull a few capacitors inside the heat sink to unscrew the diode. The entire operation was done with tweezers and tons of patience. It sounds like your method might be a better repair strategy.

Congrats! ~L-J-7~

[kbob]

Re: Dell 3008wfp faulty power supply

Way to go! That's interesting how you managed to change it without pulling the heatsink. I did also, but in a different manner. What I did was pull a few capacitors inside the heat sink to unscrew the diode. The entire operation was done with tweezers and tons of patience. It sounds like your method might be a better repair strategy.

Congrats! ~L-J-7~

I could 'just' catch the nut with some bent long nose pliers. And a screwdriver on an angle from the other side. Then I used a pair of side cutters to pull the diode while keeping the solder on the reverse wet.

When replacing I did;t manage to slip the little insulating thermal pad back behind the diode, Instead I used some good quality CPU heat sink paste - This had the added benifit of sticking the diode inplace while I soldered it in.

Got the nut and bolt back in with some locking bent end locking tweezers . I also re pasted the top of the heatsink when I replaced it. and it works!! Very happy.

BTW; working with leadfree solder is terrible - I could'nt find the good old stuff here in CH. I had a pad lift slightly just because the flux and flow properties are so bad. I need to find a nice chinese ebay seller with some old solder for sale lead/tin

-Bret

[embalse]

Re: Dell 3008wfp faulty power supply

I also re pasted the top of the heatsink when I replaced it. and it works!! Very happy.
-Bret

Did you use CPU thermal paste for this as well?

[Th3_uN1Qu3]

Re: Dell 3008wfp faulty power supply

When replacing I did;t manage to slip the little insulating thermal pad back

Remember not to do that again. Unless the new diode has a plastic back, the whole heatsink is now at 24 volts. This isn't an issue if only one part is in direct contact (in this case, the diode) and the voltages aren't dangerous, but some manufacturers have the habit to insulate all but one part from the heatsink, and when you directly bolt another one to that heatsink without noticing, boom, you shorted the PSU.

[tom66]

Re: Dell 3008wfp faulty power supply

Even worse, you just shorted 24V to 5V, maybe. Bye bye main board!

[embalse]

Re: Dell 3008wfp faulty power supply

Am having difficulty sourcing lead solder locally.
I have found one which is 50% tin 50% lead. Is this ok to replace the diode?

If not can you recommend the best % ratio.

[kbob]

Re: Dell 3008wfp faulty power supply

Did you use CPU thermal paste for this as well?

I did - Used the rest of the tube here. Reading the replys now about making sure the insulating backing was replaced on the diode. I wonder if this is all that's stopping the metal rear of the monitor from becoming live.

I'm trying to look up the physical packaging of the diode I bought to see if the metal back and screw in are infact live voltage. I guess as the thermal paste heats up and the monitor moves I might find out if there is a short!

[kbob]

Re: Dell 3008wfp faulty power supply

Am having difficulty sourcing lead solder locally.
I have found one which is 50% tin 50% lead. Is this ok to replace the diode?

If not can you recommend the best % ratio.

That's good. That was what the old style mix used to be. It's what I remember being the norm 15 years ago as a student

Your lucky to find this in the EU.

[embalse]

Re: Dell 3008wfp faulty power supply

That's good. That was what the old style mix used to be. It's what I remember being the norm 15 years ago as a student

Your lucky to find this in the EU.

Thanks for the confirmation.

[embalse]

Re: Dell 3008wfp faulty power supply

Ok. I am trying to remove the heatsink by desoldering the two corners of the heatsink and the two diode´s attached to it.

The corner solder circled in red is larger that the desolder gun tip I have.

How did other members desolder these joins?

[selldoor]

Re: Dell 3008wfp faulty power supply

Have you tried with de solder braid?
First add some of your leaded solder - will help.
Pre heat the whole area and the heatsink with a hairdrier or very very gently with a hot air gun.
If you dont have braid do you have any tv coax or audio coax - try and cut a strip of the braid sheath and coat it with flux -it should then mop up the solder.
I think you will need at least a 40watt iron.

[embalse]

Re: Dell 3008wfp faulty power supply

Thanks selldoor for the tip.

Would you recommend using braid to desolder the diode pins (see pic) also?

My gun does not seem to be all that great, either that or it is me.

[selldoor]

Re: Dell 3008wfp faulty power supply

I have never owned a de solder gun so I have always used braid and when I have mislaid it, make my own as mentioned. So yes should be ok to use braid on diode pins again add a little of your lead solder

[embalse]

Re: Dell 3008wfp faulty power supply

I have never owned a de solder gun so I have always used braid and when I have mislaid it, make my own as mentioned. So yes should be ok to use braid on diode pins again add a little of your lead solder

Thanks

[embalse]

Re: Dell 3008wfp faulty power supply

Ok, I have remove the bad diode and am about to put the new D22 diode back in.

I have noticed the old diode has a rubber band round the last connection.

Is this important, should I put it on the new diode, or does it not matter. Please see pic which explains it better than I have.

[Lumberjack777]

Re: Dell 3008wfp faulty power supply

Ok, I have remove the bad diode and am about to put the new D22 diode back in.

I have noticed the old diode has a rubber band round the last connection.

Is this important, should I put it on the new diode, or does it not matter. Please see pic which explains it better than I have.

That appears to be a ferrite bead. And yes its important. I'll quote from an article I read on that......

"Since all Schottkys are not created equal, we must be generally conscious of the dV/dt ratings of Schottky diodes. The final solution here was a small ferrite bead inserted on the leg of the Schottky diode. This smoothened out the wiggle, reduced the EMI dramatically in the bargain."

Good luck! ~L-J-7~

[budm]

Re: Dell 3008wfp faulty power supply

That is basically a one turn inductor.

[embalse]

Re: Dell 3008wfp faulty power supply

That appears to be a ferrite bead. And yes its important. I'll quote from an article I read on that......

"Since all Schottkys are not created equal, we must be generally conscious of the dV/dt ratings of Schottky diodes. The final solution here was a small ferrite bead inserted on the leg of the Schottky diode. This smoothened out the wiggle, reduced the EMI dramatically in the bargain."

Good luck! ~L-J-7~

That is basically a one turn inductor.

Arh I could not wait I put in the replacement STPS60170CT diode without it as it did not come with one.

Did anyone else put one on their STPS60170CT diode?

Anyway all seems to be working, my 3008WFP is repaired and working.