Hi,
ASUS Z62h, motherboard Z62h, rev 2.1G.
Main problem is that it will not turn on. Somebody has alreade been trying to repair it with no sucess. Firstly I replaced one big FET (FDD6680)near the DC connector that was shorted. After that consumption rose to about 20mA.
Signals on MAX8725:
DCIN 19V
ACIN 3,87V@19,6V in DC connector
REF 4.121V
ACOK 2,5V

No 3,3V nor 5V presists on TPS51020

PU201 78L05 input 19V, output 14,8V.

On TPS51202 replaced - nothing helped. Both FET-s on 5 and 3.3V generation are replaced - no help. Voltages at TPS:
DDR - 18V
REFx 0,1-1V [What that should be?]
PGOOD 0,7V [wrong because no voltages at 3,3V and 5V?]
REG5_IN - 0V
VREG5 - 5V
VIN - 19,5V
VBST1 - 4,5V
VBST2 - 4,5V

While connecting the voltage at DC connector some ticking sound is heardable near DC connector.

If board is producing "ticking sound" - it seems like you have shorted load on 3.3 or 5V load.
Check resistance of 3.3 and 5v cirquits.

Unfortunately no short at either line, both about 40kOhm and loading (capacitors). I also tried to unsolder PJP202 and PJP201 that isolate the power rail from MB but still nothing.

PS! Originally on the MB there were TPS51020, i replaced it with PS51020 from other ASUS S96S MB.

Check ENBL on 9 and 10 pin TPS51020.
Also, check, does the FETs is OK?
Is 19V is stable, not pulsing?


PS. TPS51020 and PS51020 itis the same.

Ok, first i must clarify that MB does only 1 tick when connecting the PSU.

19V is stable, it seems that VSUS_ON [ENBL1 and ENBL2 on TPS] is 0V. It is generated by KB3925, but on what basis? What signals affect it?

Look here.
I think some wrong here.
that is pdf for it http://pdf1.alldatasheet.com/datasheet- ... 78L05.html
after repair that, you can try to find, why tps51020 is not worked.

78L05 is ok, the voltage drop across it is 5V. Voltage drop over the H431BN is 9,8V so the overall output voltage is ~14,8V. According to 431BN datasheet the ideal output voltage with this setup should be 14,1V - so this circuit is OK. Also i am missing the VSUS_ON signal that switches this +12VSUS signal.

Now i noticed some bad things: The FDD6680 that was shorted happened to be 3VAO power line fet that was driven by PU5401 [APL431] zener. According to the datasheed the 34k/20k resistor settings give ref voltage of 2,459V and after the FET there should be 6,6V. Now after replacing the FET and the zener I got there 6,6V, but...before there were 19V directly from the line AC_BAT_SYS through the shorted FET before. Now looked the schematics and main power cunsumers on that line are BIOS and ENE chips. They are both probably dead now. I can replace them but since i got 6,6V on the 3VA circuit i am a fraid to frie both of them again. If anyone could measure the board what voltage is suposed to be there.

It seems to be typical fault of that type of machine. Few days agao I got a noteboot thats ENe chip was burned to crisps...and the same FET shorted thus feeding 19V to 3V rail. At the moment the Mb is given back to the customer and topic closed.