Dead acer 7750g

[giulio93]

Re: Dead acer 7750g

after some research for Acer MB this is normal its 51on logic on power switch 19V , TEST AGAIN D21 short pin 2 & 1 to see any changers on pin 117 100 in EC
U35 voltage on all pins did you flash BIOS ? any led lights up in the MB ?
U39 U35 U4 voltage on all pins resistance to GND pin 123 all 3 IC with out power note separately

I noticed the U35 was not solder on properly. I resold it and now the pc powers on and stay in that state. The problem now is nothing on screen. Totally black screen also with an external one. What could be? Bad bios chip? The bios chip is the U35? If I remember good U35 and U40 were replaced with an already programmed ones

[giulio93]

Re: Dead acer 7750g

Update. I tried a Clear cmos, and change the ram but same result. The power led works. The fan works. If I plug the HD it spins. I noticed that the current cunsumption is low. About 0.27A

[Techtiger]

Re: Dead acer 7750g

Page 40 of Schematic you can find DC to DC & VS section 5 IC to test in put voltage and out put voltage note down

Voltage on Q6 all pins & Ram slot pin 30 supply ? What are the missing voltage on the coils (PL) ?

Bios that you flash is a working bin ?

[giulio93]

Re: Dead acer 7750g

Page 40 of Schematic you can find DC to DC & VS section 5 IC to test in put voltage and out put voltage note down

Voltage on Q6 all pins & Ram slot pin 30 supply ? What are the missing voltage on the coils (PL) ?

Bios that you flash is a working bin ?

I don't understand which IC I have to check. Do I have to measure while the pc is power on? For the bios chip which one is? U40 or U35? This 2 chips were already programmed

[giulio93]

Re: Dead acer 7750g

Page 40 of Schematic you can find DC to DC & VS section 5 IC to test in put voltage and out put voltage note down

Voltage on Q6 all pins & Ram slot pin 30 supply ? What are the missing voltage on the coils (PL) ?

Bios that you flash is a working bin ?

Q6
pin power off power on
1 0 1.52
2 3.3 3.3
3 0 0

For pin30 of ram slot i mesure on the R63 and i get 1.52 when pc is power on and 0 when it's off.

Which coils have I to check?

[Techtiger]

Re: Dead acer 7750g

I don't understand which IC I have to check. Do I have to measure while the pc is power on? For the bios chip which one is? U40 or U35? This 2 chips were already programmed

Test the voltage out put side

[giulio93]

Re: Dead acer 7750g

Test the voltage out put side

Pin 1-2-3 of U7 and U14? For the bios chip do you know which ones it's the bios chip and what is the other?

[giulio93]

Re: Dead acer 7750g

If the question was about this the IC, In U14 I have 1.8V and on U7 I have 1.52V

[Techtiger]

Re: Dead acer 7750g

I don't understand which IC I have to check. Do I have to measure while the pc is power on? For the bios chip which one is? U40 or U35? This 2 chips were already programmed

U39 U25 U4 U14 U7 pin 1 to 3 are connected so mesure the supply of any and note down for DC to DC & VS supply you have to mesure voltage when the MB is on , for Bios U35 BIOS IC is located near EC so that is your EC bios U40 near PCH that is your Main BIOS
Which one did you flash ? Was it a working bin file ?

[Techtiger]

Re: Dead acer 7750g

Page 40 of Schematic you can find DC to DC & VS section 5 IC to test in put voltage and out put voltage note down

Voltage on Q6 all pins & Ram slot pin 30 supply ? What are the missing voltage on the coils (PL) ?

Bios that you flash is a working bin ?

Take a pic of the MB note down all the voltag's of the coils for example PL 23 PL19 PL 10 and upload

[Techtiger]

Re: Dead acer 7750g

U5 IC voltage note down with PIN number ?

[giulio93]

Re: Dead acer 7750g

Take a pic of the MB note down all the voltag's of the coils for example PL 23 PL19 PL 10 and upload

Sorry i am sure is my foult but I dont understand very well. Can you say exactly which measure I have to take? If you say me all the pins of all the components I will take all the masurments. For the bios chip i didnt programmer anything. I buy then already programme from the seller. Which bios chip manager the powering on? And what do the other one?

[Techtiger]

Re: Dead acer 7750g

Sorry i am sure is my foult but I dont understand very well. Can you say exactly which measure I have to take? If you say me all the pins of all the components I will take all the masurments. For the bios chip i didnt programmer anything. I buy then already programme from the seller. Which bios chip manager the powering on? And what do the other one?

If you have informed earlier that Bios chip was already programmed by some one else this would be much easier, no need of testing you have to flash bios from the forums with a working bin file , to do that you need a special tool

[giulio93]

Re: Dead acer 7750g

If you have informed earlier that Bios chip was already programmed by some one else this would be much easier, no need of testing you have to flash bios from the forums with a working bin file , to do that you need a special tool

which is the bios chip (U40 or U35)? And what the other do?

[Techtiger]

Re: Dead acer 7750g

Read Post 49 I have explained EC bios U35 Main Bios U40

[giulio93]

Re: Dead acer 7750g

Read Post 49 I have explained EC bios U35 Main Bios U40

Ok, so considering the fact of the pc turns on I assumed the U35 is solderd properly and programmed properly. Correct? For the main bios can I use the .bin founded on the acer site?

[giulio93]

Re: Dead acer 7750g

The U40 chip is this one. I have a bios programmer. Is this a 25xx or 24xx? 24 is also named I2C or it's a common name for both ones? https://www.digikey.it/en/products/d..._medium=buyNow

[mon2]

Re: Dead acer 7750g

24xx will be I2C interface devices. This means there will be a SCL & SDA pin to communicate with this memory device.

25xx is a different interface and is the SPI mode of communication. For such memory devices, there will be:

CS = chip select
MOSI = Master Out; Slave In pin
MISO = Master In; Slave Out pin
CLK = clock pin

[giulio93]

Re: Dead acer 7750g

24xx will be I2C interface devices. This means there will be a SCL & SDA pin to communicate with this memory device.

25xx is a different interface and is the SPI mode of communication. For such memory devices, there will be:

CS = chip select
MOSI = Master Out; Slave In pin
MISO = Master In; Slave Out pin
CLK = clock pin

Sorry for the stupid question. How can i recognise the difference just looking at the chip?

[mon2]

Re: Dead acer 7750g

Read off the laser markings from the top side of the IC. Post the details here.