Dell E7470 with burned MEC5085

[RS990]

Hi everyone, new to the forum and in electronics, I have a Dell E7470 that had a little bit of liquid damage, it shorted out the pin 1 and 2 on the USH connector which are +PWR_SRC_R and +3.3V_ALW2_R, I assume that the +PWR_SRC_R was sent to the +3.3V_ALW2_R and burn the MEC5085, the MEC5085 had 2 rip pads that I fixed. I have changed the USH connector, ribbon cable and the MEC5085-LZY-3, Does the 5085 need to be programmed? The power button does nothing, have no voltage on any of the power inductor except on the main 19v and 13.6v near the battery connector and have 3v not 3.3v at the power button??

Here are picture of the damage.

[RS990]

Re: Dell E7470 with burned MEC5085

Schematic for Dell_Latitude_E7470_Compal_LA-C461P_Rev1.0

[bbanana]

Re: Dell E7470 with burned MEC5085

Hi everyone, new to the forum and in electronics, I have a Dell E7470 that had a little bit of liquid damage, it shorted out the pin 1 and 2 on the USH connector which are +PWR_SRC_R and +3.3V_ALW2_R, I assume that the +PWR_SRC_R was sent to the +3.3V_ALW2_R and burn the MEC5085, the MEC5085 had 2 rip pads that I fixed. I have changed the USH connector, ribbon cable and the MEC5085-LZY-3, Does the 5085 need to be programmed? The power button does nothing, have no voltage on any of the power inductor except on the main 19v and 13.6v near the battery connector and have 3v not 3.3v at the power button??

Here are picture of the damage.

new MEC5085 need to program
you cant do anything before replace that burned EC.

[mcplslg123]

Re: Dell E7470 with burned MEC5085

He has already replaced MEC5085.

[RS990]

Re: Dell E7470 with burned MEC5085

Yes, the MEC5085 has been replaced, I tried to read the schematic but it's complicated its like deciphering Egyptian hieroglyphs . What power rails power on when you plug in the ac adapter? I know you need 3.3v at the power button but what supplies the 3.3v? I wish I knew someone in my area to explain those schematics. The MEC5085 came from Aliexpress so maybe it's a dud, I bought 2 so I will try the other one just in case!

[reformatt]

Re: Dell E7470 with burned MEC5085

Power sequence on pg 55 is where you start. 19V on 3.3V rail is never a good thing, so you'd have to assume anything on the +3.3V_ALW2 rail is suspect. MEC's need a programmer like SVOD to program via JTAG.

https://cdn.badcaps-static.com/pdfs/...bfb7fc7e38.pdf

[RS990]

Re: Dell E7470 with burned MEC5085

Power sequence on pg 55 is where you start. 19V on 3.3V rail is never a good thing, so you'd have to assume anything on the +3.3V_ALW2 rail is suspect. MEC's need a programmer like SVOD to program via JTAG.

https://cdn.badcaps-static.com/pdfs/...bfb7fc7e38.pdf

Now I'm confuse, on the Discord someone told me this..
"i just check the schematic
[10:50 AM]
i thin dont need to program"

The PDF you gave me is for the MEC5075 on the LA-9591P motherboard mine is the MEC5085 on the LA-C461P, is it the same thing?

[reformatt]

Re: Dell E7470 with burned MEC5085

Datasheet for the MEC5085 is no longer published by Microchip, however I have it listed as having a 288kb flash. So yes, it needs to be programmed. The SVOD document I linked is the method used to program a MEC chip for JTAG (the exact chip is irrelevant). You'll have to find the corresponding points in the schematic to hook up to for TDI, TDO, TMS, CLK etc. BIOS + EC dumps are available for this model online.

I know others who can't be bothered to program (like Sorin on his YT channel) so buy the chip off an eBay vendor who pre-programs them.

[RS990]

Re: Dell E7470 with burned MEC5085

Datasheet for the MEC5085 is no longer published by Microchip, however I have it listed as having a 288kb flash. So yes, it needs to be programmed. The SVOD document I linked is the method used to program a MEC chip for JTAG (the exact chip is irrelevant). You'll have to find the corresponding points in the schematic to hook up to for TDI, TDO, TMS, CLK etc. BIOS + EC dumps are available for this model online.

I know others who can't be bothered to program (like Sorin on his YT channel) so buy the chip off an eBay vendor who pre-programs them.

Thanks much appreciated, I will look on eBay for a pre-programme chip and take a look for a programmer if it's affordable.

[reformatt]

Re: Dell E7470 with burned MEC5085

SVOD is a bit expensive, but it's a great tool. Only justified if you are a pro really.

Another option is to steal it off a donor board.

[mcplslg123]

Re: Dell E7470 with burned MEC5085

Finding JTAG pins like TDI/TDO etc will not be enough. You need to re-arrange/remove some resistors to activate JTAG. So its bit complicated and many users just avoid it as @reformatt has said.

[rediii]

Re: Dell E7470 with burned MEC5085

try to buy a faulty board for cheap... it's easier for you