Question about Dell Latitude D505 Notebook

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D20 Diode value on Motherboard.

Hi folks. On the M/B, bottom of the connector where the power switch daughterboard plugs to the M/B, is a burned diode, with a pc board trace id of D20. Does anyone know what value this diode is? I can R&R, but it would be nice to have a value for this part... Also, if anyone knows what might cause this fried condition, that would be helpful too. I have a new power jack I will put on if I can figure out and replace the diode. Probably got fried from a shorted least that's the theory. I have a nice close up pic if there is a way to post that here... SetiRich!

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Re: D20 Diode value on Motherboard.

Contact Dell support. Tell them that you were told by a tech (that has repaired many of these problems) that you believe you have a motherboard with leaky capacitors (do not mention the burnt out diode, just tell then it no longer boots). After much interaction with Dell technicians, it turns out that dell has extended the motherboard warranties of most of their PC's including laptops. I know of two people so fat that have had Dell warranty repairs done, even though the system was out of warranty. Once they hear "leaky capacitors" they will advise you that even though your unit is out of warranty, they will replace it. Hope that helps! Best regards

Posted on May 04, 2007

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This is the Notebook PC category.

Posting, "....and the VoltageS are correctly on the power supply.....makes me think we are talking about a Desktop PC here.

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Green color LED (Light Emitting Diode) referred to, is the motherboard power LED.

All the power cables from the Power Supply, plugged into the motherboard?




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Found on the back for a desktop computer, usually next to the Windows product key; or up on the side of the computer tower (Case)
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While I wait for your reply, in the meantime unplug the power cable to the optical drive (CD/DVD drive), and the harddrive.
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Plug the computer back into power. Motherboard LED light on?
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Hold the phone..............or are you referencing to the Green LED light that is on the back of the Power Supply?

Scroll down a little to the photo. That Green LED light?


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My toshiba l300 freezes or switches off when i plug in ok on battery tho! ???

Suggest laptop has a problem with Power MOSFETs in the power section area of the motherboard, and/or MLCC ceramic capacitors that are nearby the Power MOSFETs.


Here's an example of the DC Power Harness;

[DC Power Jack is the jack on the laptop, that you plug the AC adapter (Charger) into.

For your model the DC Power Jack, is connected to wires that end in a plug. (Harness)
The plug plugs into a small white connector on the motherboard.
The DC Power Jack itself sits in a channel, along the outside edge of the Base Enclosure. (Bottom Cover) ]

Toshiba Equium L300 series of Notebook PC, motherboard general example; Top and Bottom views,

Scroll down to the Yellow 'frame', and click on the first photo shown,
[ Original Part - ebid-deaklz ]

Look at the Top Right corner, and at the mounting hole.
There is a aluminum looking cylindrical metal spacer below it.
To the bottom left of that cylindrical metal spacer is a white connector for a plug.

The plug to the DC Power Harness.
This is the power section.
Note the Power MOSFETs on the motherboard.

One to the immediate bottom right, of the white motherboard connector mentioned above, one above to the top left of the white connector, and close to the outside edge of the motherboard.

This is a general example of a Power MOSFET used in this type of application, and used in a LOT of laptops; (Not indicating this model is what your motherboard power section uses),

Note the eight J-leads used on both sides. (4 per side)

More information using HP Pavilion dv6000 series, and Pavilion dv9000 series Notebook PC's, as an example,

Note the second photo down with the Alpha and Omega Semiconductor - AO4407 - Power MOSFET, circled in Yellow;

To the immediate right of the AO4407 is a small rectangular object, with a dark wide band in the middle.
This is a Ceramic Capacitor.
(Multi-Layer Ceramic Capacitor, and Surface Mount Device;

There is one above it, one above that, and one to the right of the top one.

Now go back to the Top View photo in the Ebay link, and view the Power MOSFETs around the white connector, on the motherboard, for the DC Power Harness.
Also the MLCC ceramic capacitors.

If you see obvious signs of damage to the Power MOSFETs, or ceramic capacitors, such as burning, blistering, or blackening, they need to be replaced.

Or replace the motherboard.

In reality you do not know if the repairs you made 'will stay'.
Already burned out electronic components you replaced, may have taken out other components, or weakened them.

More logical is to replace motherboard, unless you are fine with opening the laptop back up again, and replacing the motherboard the second time around.

If you do wish to attempt repair, Power MOSFETs are about a dollar (USD), and ceramic capacitors range around 52 cents to 80 cents.

Take the Fairchild Semiconductor International - FDS6679 - Power MOSFET, for an example,

(Scroll down)



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HP Support > Pavilion a1514n desktop computer > Main page,

Product information > Product specifications > Motherboard specifications, RC410-M (Asterope 2)

Scroll down to the motherboard illustration, and motherboard photo under it.

A) 24-pin ATX main power cable:

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Whitish connector with 24 socket holes. Two columns of 10 socket holes.
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[Note* Color of connectors does NOT matter ]

Note the power cable connector in the middle photo, and the photo to the far right with the power cable plugged into the motherboard.

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Also > Laptops for Parts.

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