I'm in the process of repairing an Acer 6530G motherboard (DA0ZK3MB6F0 Rev:F). This is one of many defective laptops / laptop parts I'm attempting the repair of to further my electronics troubleshooting skills.
For this one, I have the appropriate schematic which got me pretty far in troubleshooting, but not all the way.
I have attached the schematic to this post.
Here's where I'm at.
+5VPCU and +3VPCU lines are okay.
I figured out that NBSWON should have 3V without pressing the power button. NBSWON comes from the SIO chip U7 pin number 95, but that voltaghe was absent in this laptop. I decided to replace the SIO chip (U7). After that, NBSWON is 3.3V as it should be. Next, I decided to check the BIOS chip (U25) with my oscilloscope. It's showing some weirdness:
Pin 1 CE (SPI_CS0_uR) - between 0 and 3V, very noisy on the scope
Pin 2 SO (SPI_SCK_uR) - between 0 and 3V, very noisy on the scope
Pin 3, 7 and 8 (+3VPCU) - 3.3V - smooth on scope
Pin 4 VSS - GND
Pin 5 SI (SPI_SDO_uR) - 0V with occasional spikes to 3.3V
Pin 6 SCK (SPI_SCK_uR)- Between 0 and 3.3V, very noisy on the scope as well
Seeing the spikey voltages from the BIOS chip, my assumption was that the BIOS chip is bad, so I took an identical chip from another 6530G motherboard and ended up with the same readings. I figured I should be seeing at least a stable RAM voltage coming from one of these pins.
Perhaps both BIOS chips are bad, however I did desolder one and was able to write to it successfully with an eeprom programmer. That probably wouldn't work with a defective chip, right? They normally throw an error when I try to do that.
I'm not sure how to proceed from here. I've checked to make sure every pin of the SIO chip is properly soldered, and they all are. Is the problem in the Bios chip, the SIO chip or might it be elsewhere?
Any help would, as usual, be quite welcome!
For this one, I have the appropriate schematic which got me pretty far in troubleshooting, but not all the way.
I have attached the schematic to this post.
Here's where I'm at.
+5VPCU and +3VPCU lines are okay.
I figured out that NBSWON should have 3V without pressing the power button. NBSWON comes from the SIO chip U7 pin number 95, but that voltaghe was absent in this laptop. I decided to replace the SIO chip (U7). After that, NBSWON is 3.3V as it should be. Next, I decided to check the BIOS chip (U25) with my oscilloscope. It's showing some weirdness:
Pin 1 CE (SPI_CS0_uR) - between 0 and 3V, very noisy on the scope
Pin 2 SO (SPI_SCK_uR) - between 0 and 3V, very noisy on the scope
Pin 3, 7 and 8 (+3VPCU) - 3.3V - smooth on scope
Pin 4 VSS - GND
Pin 5 SI (SPI_SDO_uR) - 0V with occasional spikes to 3.3V
Pin 6 SCK (SPI_SCK_uR)- Between 0 and 3.3V, very noisy on the scope as well
Seeing the spikey voltages from the BIOS chip, my assumption was that the BIOS chip is bad, so I took an identical chip from another 6530G motherboard and ended up with the same readings. I figured I should be seeing at least a stable RAM voltage coming from one of these pins.
Perhaps both BIOS chips are bad, however I did desolder one and was able to write to it successfully with an eeprom programmer. That probably wouldn't work with a defective chip, right? They normally throw an error when I try to do that.
I'm not sure how to proceed from here. I've checked to make sure every pin of the SIO chip is properly soldered, and they all are. Is the problem in the Bios chip, the SIO chip or might it be elsewhere?
Any help would, as usual, be quite welcome!
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