Dell E6540 No RAM detected.

[Andreasbest]

Re: Dell E6540 No RAM detected.

Pin 11 of PU200 not shorted to ground.
8.3KΩ soldered the same with the donor MB.

[Spider1211]

Re: Dell E6540 No RAM detected.

are you measuring across PR203 or with ground?

[Andreasbest]

Re: Dell E6540 No RAM detected.

are you measuring across PR203 or with ground?

Across.
With ground i get 20KΩ on the pin in side of pin 11 and 28KΩ on the other pin.

[Spider1211]

Re: Dell E6540 No RAM detected.

looks like a faulty PR203. Connect power, turn on and check if you have 5V on 1 side of the resistor. If so, measure PR203 off the board and if faulty replace it.

[Andreasbest]

Re: Dell E6540 No RAM detected.

I have 5v on both pins of PR203.
I get 20KΩ on the pin in side of pin 11 and 28KΩ on the other pin on the donor board too.

[Spider1211]

Re: Dell E6540 No RAM detected.

You said in post #17 pin 11 is 0V, how come you have 5V on both sides now? Are you sure pin 11 is 0V? Measure it on the IC directly. If you still have 0V, its likely the trace from PR203 to pin11 is broken. Check continuity between these 2 points with power removed.

[Andreasbest]

Re: Dell E6540 No RAM detected.

I was checking this right now, yes now i see 5v in pin 11.
Probably i made a bad contact between probe and pin.

[Spider1211]

Re: Dell E6540 No RAM detected.

Remeasure voltage on the pins requested earlier and report back.

[Andreasbest]

Re: Dell E6540 No RAM detected.

All like i said before except the pin 11 with 5v.
All others the same.

[Spider1211]

Re: Dell E6540 No RAM detected.

Check PR206 (if available), PR210 & PR208(check if its 0 ohms).

[Andreasbest]

Re: Dell E6540 No RAM detected.

PR206 not present
Not sure where PR210 is
PR208 not present too

[Spider1211]

Re: Dell E6540 No RAM detected.

I think PR208 should be present. It does not seem to be a No stuff according to attached schematic. Check on your donor board.

Check for short to ground on pin 7 and 8 of PU200.

Try looking for the boardview or make a request in the schematic section if you cant find it.

[Andreasbest]

Re: Dell E6540 No RAM detected.

Found boardview too. Still haven't managed to open it correctly (can't find a compatible program)
If anyone manage to open it let me know how you did it
Also close photo of PU200 to see yourself what is there and what is missing, exactly the same with donor board.
No short to ground in pins 7 and 8

[Spider1211]

Re: Dell E6540 No RAM detected.

You can use Allegro software to view .brd files.

[Andreasbest]

Re: Dell E6540 No RAM detected.

I tried with Allegro but it shows the SMD as 7 or 5.
This software is really hard to use, actually it has a loooooooot of options.

[Spider1211]

Re: Dell E6540 No RAM detected.

Try these setting under "Visibility" tab. You have to really zoom in on the pads to see their name.

Toggle the green square in Top or red square in Bottom to switch their respective layer on or off.

[Andreasbest]

Re: Dell E6540 No RAM detected.

Ok i did it.
Still don't see the SMD names, check the area we interest for example.

[Spider1211]

Re: Dell E6540 No RAM detected.

Go on the "options" tab then do the following:
- Select "etch" in 1st drop down menu, then select "Top" in 2nd drop down menu and click on the small square. This will display the tracks. Do same for "Bottom" if you need to see the bottom tracks as well.

- Next select "Ref Des" then choose:
"Assembly Top" to display components reference (R761, etc)
"Silkscreen Top" to display IC reference (u46, etc)

Dont forget to click the small square to activate it.

Play around with the other layers to see what suits you.

[Andreasbest]

Re: Dell E6540 No RAM detected.

Ok good now.
So PR208 is indeed missing. It's the 3rd SMD from bottom and as you can see in the photo i upload before there is no SMD in this place.

[Spider1211]

Re: Dell E6540 No RAM detected.

Boardview will not tell you if the component is there or not. It'll just let you know the position on the board and its electrical connection.

Schematic is where you get the info for no stuff parts etc. Do cross check on your donor board to confirm if its indeed missing or not.