Dell Vostro 3501 - no signs of life after BIOS read

[someonenotyou]

Hi.

I have a laptop Dell Vostro 3501 which did not POST. When connected to power supply and turn it on, the keyboard backlight would turn on but nothing else. Sometimes there was 1 BEEP code indicating problems with BIOS.

Then I disassembled it to read the BIOS chips. It had 2 - 64mbit and 128mbit. I connected CH341A (with 3.3v mod) to both of the chips (still soldered on main board) and read them.

After I reassembled laptop back and tried to turn it on. Now there is no sign of life. Not even keyboard backlight.

Then I took the motherboard out to check for shorts. I could not find any. Then I pugged in the power supply. I get 19V on main rail, 5V, 3.3V and 1.8V. But no sign of life. Then I attached bench power supply on main rail with 19V and 0,2amps. There is no current draw.

While the board is connected to the power supply and it gets 19V, I measured that the main power rail is also shorted to ground with 0ohms. When power supply is disconnected, the main rail to ground shows 3 Mega Ohms and falling. Is it supposed to be shorted to ground while it receives 19V?

What could cause the board to be dead after BIOS read?

Thank you.

[SMDFlea]

While the board is connected to the power supply and it gets 19V, I measured that the main power rail is also shorted to ground with 0ohms. When power supply is disconnected, the main rail to ground shows 3 Mega Ohms and falling. Is it supposed to be shorted to ground while it receives 19V?

Resistance measurements should only be made with an unpowered board, No AC, No battery.

[someonenotyou]

At the moment I have gotten to this DC-DC controller - RT3612EBGQW-03.


I have measured that +5VALW, +19VB_VCCIN, +1.05V_VCCST are present. The +3VALW is missing.
As I understand, this DC-DC converter is for powering CPU, correct? And if +3VALW is missing then CPU gets no power.
On other parts of the board +3VALW is present. But it is hard to trace where the chain is broken going to this controller.

[someonenotyou]

Just went through schematics power diagram measuring voltages and power up sequence and it seems, that all stops at SPI chip.


Could it be that the BIOS chips are bad? But I am still able to read them.

[SMDFlea]

Sometimes there was 1 BEEP code indicating problems with BIOS.
Then I disassembled it to read the BIOS chips. It had 2 - 64mbit and 128mbit. I connected CH341A (with 3.3v mod) to both of the chips (still soldered on main board) and read them.
After I reassembled laptop back and tried to turn it on. Now there is no sign of life. Not even keyboard backlight.
What could cause the board to be dead after BIOS read?

Are both chips SOP8, the ones with legs that stick out, or are they WSON8 the flat ones with just a bit of solder sticking out. Which type of clip did you use. What programmer software did you use.

Did you make backups and check them to make sure they were good. Which bios did you flash to both chips. Have you checked around both chips for any parts that you might have damaged or knocked
off with the clip.

[someonenotyou]

Are both chips SOP8, the ones with legs that stick out, or are they WSON8 the flat ones with just a bit of solder sticking out. Which type of clip did you use. What programmer software did you use.

Did you make backups and check them to make sure they were good. Which bios did you flash to both chips. Have you checked around both chips for any parts that you might have damaged or knocked
off with the clip.

They are SOP8 type chips.
I used this clip:

Software used - NeoProgrammer 2.2

At the moment I am just getting into BIOS flashing, still got to learn what I am looking at when I open it with UEFITool.

At first, I just read the BIOS chips and requested a new BIOS (which no one responded to). I did not flash them. When I reassembled the laptop and got no sign of life, I then tried to flash one of the 3501 BIOS from here - Dell FDI55 LA-J081P Rev 1.0 Bios Bin - Badcaps to possibly get any sign of life..

Inspecting around the BIOS chips with microscope, there is no damage, no missing components, the legs are firmly soldered to the pads.

[rogfanther]

What is the voltage on bios chip pin 8 ?

Please post pics of the bios chips region also.

[mcplslg123]

I dont trust this CH341A programmer at all. It often fails to program the chip correctly though there is no error message.

Since it was switching on prior to bios flash and there is no damage in the spi area, it has to be bios not being written correctly by CH341A.

I trust RT809F/H for programming bios. SVOD4 is one of the best for SIO programming but not that reliable in case of SPI programming.

Have seen many cases where bios written with SVOD4 fails to give display whereas the same file programmed with RT809F gives display.

So bios programmer can be the issue here.

[someonenotyou]

What is the voltage on bios chip pin 8 ?

Please post pics of the bios chips region also.

Voltage on PIN 8 of both chips are 3.408V
Here is picture of the area of BIOS chips.

[someonenotyou]

I dont trust this CH341A programmer at all. It often fails to program the chip correctly though there is no error message.

Since it was switching on prior to bios flash and there is no damage in the spi area, it has to be bios not being written correctly by CH341A.

I trust RT809F/H for programming bios. SVOD4 is one of the best for SIO programming but not that reliable in case of SPI programming.

Have seen many cases where bios written with SVOD4 fails to give display whereas the same file programmed with RT809F gives display.

So bios programmer can be the issue here.

No, it did not switch on before the flash. As I said, I read the BIOS chips, made the request for a new BIOS. While I was waiting for anyone to reply, I reassembled the laptop and noticed that it had no sign of life. Only then I tried to flash new BIOS.
If it was programmers fault, then the checksum of the file I did flash and the file I dumped after the flash would not match.

[mcplslg123]

As per post#1, it was turning on with kbd backlit coming up.

[someonenotyou]

As per post#1, it was turning on with kbd backlit coming up.

Yes, but also in Post#1 there is nothing mentioning about BIOS flashing.

[someonenotyou]

Are both chips SOP8, the ones with legs that stick out, or are they WSON8 the flat ones with just a bit of solder sticking out. Which type of clip did you use. What programmer software did you use.

Did you make backups and check them to make sure they were good. Which bios did you flash to both chips. Have you checked around both chips for any parts that you might have damaged or knocked
off with the clip.

Thank you SMDFlea for a clean BIOS.
Unfortunately, there are still no sign of life after flashing the BIOS.

I don`t know if it is related, but there is no charger light as well when I plug in the adapter, even if battery is connected.
Also, where it is supposed to be 19V, with no adapter connected, I get battery voltage (10.25V). Should it be like that?

[mon2]

Attach the power adapter that is recommended for this logic board.

Measure the voltage to ground on each group of pins of mosfet PQB11.

Measure:

source (1-2-3) ; pick any one of these
gate (4)
drain (5-6-7-8)

Post each measurement. If the adapter is functional, you should have ~19v on the drain pins. To allow for the voltage to pass onto the main power rail, the gate voltage should be ~25 volts to enable this N-channel mosfet. Then the same voltage should pass onto the source (1-2-3) pins.

[someonenotyou]

Attach the power adapter that is recommended for this logic board.

Measure the voltage to ground on each group of pins of mosfet PQB11.

Measure:

source (1-2-3) ; pick any one of these
gate (4)
drain (5-6-7-8)

Post each measurement. If the adapter is functional, you should have ~19v on the drain pins. To allow for the voltage to pass onto the main power rail, the gate voltage should be ~25 volts to enable this N-channel mosfet. Then the same voltage should pass onto the source (1-2-3) pins.

I got these measurements:
1-2-3 - 19.83V
4 - 24.51V
5-6-7-8 - 19.83V

[someonenotyou]

I did some more measurements on the startup sequence:

It seems that everything stops at SIO_SLP_S4# where PCH sends enable signal for 2.5V. When I press power button, my multimeter does not register anything.
Where should I look now?