Hi, have a NAS QNAP model TS-453B with QY47 motherboard.

When power is applied to dc-in conector, (12v) it starts to drain 80 mA. from PSU.

Power led blinks at low rate and does nothing.

There are some activity in ec-bios but no activity at all at main-bios.

All main voltages are present but no cpu vcore.

This board mounts a IT8528E kbc, but connections are different to other boards with the same kbc.

(only a few pines like spi bus, ec-RST#, and 3v. lines are connected like in Quanta U93)

Without schematic is a nightmare to find out signals like RSMRST# or HWPG.

Can someone help me with this board?

you can check is there an EN signal for CPU PWM IC.

This board have 2 identical chips for power the cpu.

One of them works perfectly well and outputs 1.05 volts.

The other one is for cpu-vcore and has no output.

this chips (3H=3H) seems to be identical to RT3601EAGQW_WQFN28_4X4.

The enable pin for this chip is pin 2, and it is low level all the time.

The Compal LA-D641P uses this chip for +VCC_VCGI.

I have replaced ITE chip (IT8528E) but not solved the problem.

Seems that SUSP# voltage are not generated by kbc chip or an intermediate circuit.

There are some chips that receives +3VALW or +5VALW in some of its pines but there are no output nor control voltage.

Can someone tell what kind of chip are those shown in the photo attached?

(u2, u3 and u19)

your photo has a bad quality.

You are right, it is very difficult to see the name on top of chip, even with microscope.

I have taken many photos, but it was with my phone camera. ( my good camera is broken)

Take a look at this better photo attached:

(Is the same kind of chip from other circuit in the same board)

Some good news.

After change the cpu without positive results, I have dedicated all my efforts to find out an equivalent of the ZSA0.

At Aliexpess website, have found that tps22965 is a direct equivalent.

The datasheet of tps22965 described it as "Integrated Single Channel Load Switch"

You can see in the datasheet that pin 3 controls the transfer input voltaje to the output.

I have found a "sot-23-3" mosfet near those tps22965, (3.3 and 5v switches) that has 3v in its drain pin a few miliseconds after power on.

Conecting the control pins to this tini mosfet, the motherboard is able to start an boot from a linux pendrive.

I know that there is a lot of work to do, but things are progresing well.