DELL 2405fpw

[Mirage00]

Re: DELL 2405fpw

The reading for the IFR5305S drain pin is 0.00V. If it is supposed to be 5V, then it is easy to verify.

I know if I had 2 identical monitors, I would have already done the voltage comparisons between the good and bad to know if the drain pin should be 0.00 or 5V.

I have a stupid question. If the drain pin (center) is not connected to anything, why doesn't it matter.

Also, I would rather not remove the other monitor and start dissembling it but if I have to I will.

[budm]

Re: DELL 2405fpw

That can be the switched MOSFET that feed the 5V B+ to the T-CON board.

[retiredcaps]

Re: DELL 2405fpw

"The IFR5305S drain should be at 5VDC. I measured this from a properly working monitor. This means a 3V Zener is incorrect. Use at least a 6.8V Zener which should be quite safe for downstream parts. I managed to supply 5V to the drain (after removing the burnt FET) from an external 5V SMPS and all works well."

Whereas I think you are saying you have 0.00 on the drain?

If the 5305S is not in the area for which the close up was requested can you do it as well.

The reading for the IFR5305S drain pin is 0.00V. If it is supposed to be 5V, then it is easy to verify.

I know if I had 2 identical monitors, I would have already done the voltage comparisons between the good and bad to know if the drain pin should be 0.00 or 5V.

[budm]

Re: DELL 2405fpw

These need to be verify:
"Hi Please can you test that orange pico fuse."

"Unless I have missed it there has been no comment on the result of your tests on the mosfets.
In the eservice post you mention it does say

"The IFR5305S drain should be at 5VDC. I measured this from a properly working monitor. This means a 3V Zener is incorrect. Use at least a 6.8V Zener which should be quite safe for downstream parts. I managed to supply 5V to the drain (after removing the burnt FET) from an external 5V SMPS and all works well."

Whereas I think you are saying you have 0.00 on the drain?

If the 5305S is not in the area for which the close up was requested can you do it as well."

[Mirage00]

Re: DELL 2405fpw

So nothing left to do from @selldoor's post?

[budm]

Re: DELL 2405fpw

That PICO is the fuse after the DC output of the main 19V power supply that supply the power to all the boards, the voltage get stepped down to lower voltage by a bunch of regulators. If that fus eis blown, the whole unit will be dead, it uses about the same aset up as the 24xx sereis monitor, single output main power supply.

[Mirage00]

Re: DELL 2405fpw

I will get the info later today! I'm glad this thread is still alive, I was getting nervous.

Once again, I must thank everyone for their time and contributions. It still amazes me that I have people who are willing to take time and help me out for no other reason than they want to.

"Oh, uh, there won't be any money, but when you die, on your deathbed, you will receive total consciousness"

[selldoor]

Re: DELL 2405fpw

Hi Please can you test that orange pico fuse.
Also can you mark on the picture with the red squares ,the part nos so we know which is which.
Perhaps a close up well lit picture of the top corner marked out by budm and the back of that area would help.

Unless I have missed it there has been no comment on the result of your tests on the mosfets.
In the eservice post you mention it does say

"The IFR5305S drain should be at 5VDC. I measured this from a properly working monitor. This means a 3V Zener is incorrect. Use at least a 6.8V Zener which should be quite safe for downstream parts. I managed to supply 5V to the drain (after removing the burnt FET) from an external 5V SMPS and all works well."

Whereas I think you are saying you have 0.00 on the drain?

If the 5305S is not in the area for which the close up was requested can you do it as well.

[budm]

Re: DELL 2405fpw

Oh that one too.

[retiredcaps]

Re: DELL 2405fpw

I am not sure (you mean the 2407), I really expect to see a transistor close by the power pin of the T-CON connector. See example of the Dell 2007.

Sorry, I meant your analysis of this monitor

https://www.badcaps.net/forum/showthread.php?t=20531

[budm]

Re: DELL 2405fpw

I am not sure (you mean the 2407), I really expect to see a transistor close by the power pin of the T-CON connector. See example of the Dell 2007. The 5V for the T-CON must be coming from 5V buck regulator some where since this monitor has only 19V power supply (I believe).

[retiredcaps]

Re: DELL 2405fpw

You sure have good memory retiredcaps.

I can't even remember what I had for lunch today. If I didn't document the almost burnt bacon and eggs, I would have forgotten.

Now is Mirage00 willing to take apart a good working monitor to save the other one?

@budm, any chance the USB board is generating any voltages that are needed by the main board like the Dell 2007fpw that you did an analysis on? The two good voltage regulators have to be getting their 3.3V from somewhere?

[budm]

Re: DELL 2405fpw

You sure have good memory retiredcaps.

[retiredcaps]

Re: DELL 2405fpw

Just have to find the service manual or if someone else may have working unit to take the voltage measurement to compare them with yours.

Mirage00 has 2 of these units as per post #31.

[Mirage00]

Re: DELL 2405fpw

It sounds like they were having problem in the power supply section. You are having "no pictures problem". May have to Google "Dell 2405fpw - no picture Displays".

Yeah, I have been searching for days. I can't find anything. Could it be the CAPS on the logic board?

[budm]

Re: DELL 2405fpw

It sounds like they were having problem in the power supply section. You are having "no pictures problem". May have to Google "Dell 2405fpw - no picture Displays".

[Mirage00]

Re: DELL 2405fpw

THis is all greek to me but you may understand it

http://forum.eserviceinfo.com/viewtopic.php?t=63329

[budm]

Re: DELL 2405fpw

Just have to find the service manual or if someone else may have working unit to take the voltage measurement to compare them with yours.

[Mirage00]

Re: DELL 2405fpw

So any ideas how I proceed?

[budm]

Re: DELL 2405fpw

No, because not all of them will be tied together, each one may be used for the regulators input and output filters for difference voltages.