Hi,
I have the motherboard W26361-W84-X-02 where it starts the CPU fan but don't show nothing at all. The problem as I saw is that the CPU don’t take a proper voltage. I measured with oscilloscope the voltages on three CPU inductors and the voltage was mVolt and the processor was a bit warm (not hot like a CPU is).
I measured the pulses from the 15,18,19 pins of ISL6565BCRZ (Multi-Phase PWM Controller) and looks OK. Also, these pulses arrive at the pin 3 of each ISL6612ECB-T (Advanced Synchronous Rectified Buck MOSFET Driver) respectively.
The problem in my opinion is at the output pin 1 that drives the high side mosfet. And in three chips ISL6612ECB-T the pulses are weak and seems like a noise.
I checked for shorts but I didn't find anything and I replace the electrolytic caps.
Also, I tried the below:
I replaced the RAM with a same and functional one (from a same second motherboard that I have).
I replaced the CPU with a same and functional one (from a same second motherboard that I have).
I check the CPU socket for bend pins and all are ok.
I have replace the BIOS chip with a same and functional one (from a same second motherboard that I have).
I have replaced all the caps in the yellow circles with brand new capacitors.
I place a buzzer on the motherboard and no beep even when I remove the RAM.
I tried some PCI tester cards and gave me the below codes:
The one of them show nothing "--".
The second show "0000".
The third show "FF".
As I saw in a "PC Analyzer Users Guide" pdf that I found on the internet:
The "00" means "Code copyng to specific areas is done. Passing control to INT 19h boot loader next.
The "FF" means "Flash ROM programming was succesful. Next restarting the system BIOS."
Do you know what these codes means in practical level?
Datasheets:
https://www.renesas.com/us/en/document/dst/isl6612-isl6613-datasheet (ISL6612, ISL6613)
https://www.mouser.com/datasheet/2/698/intersil_fn9135-1277737.pdf (ISL6565A, ISL6565B)
https://dimm.me/wp-content/uploads/PC_Analyser_Instructions_PCI_ESA_Card_FINAL_OCR-libre.pdfP.S. I can’t through the motherboard in the bin because it is from an old machine and unfortunately works only with this motherboard with any other similar