#45958 by JEWilson
Thu Aug 30, 2007 3:32 pm
Apologies if I am off topic

This mobo is completely dead - rec'd this way.
As mobo soft-start does not even does not initiate, I suspect
+12v line dead. PSU known good, RAM known good, CPU known

This mobo uses an Intersil ISL6556CBC PWM IC and is appears to
be based on the Intel VRM/VRD 10.x specification. Further uses dual (HIP6602CBC) and single (HIP6601CBC) MOSFET drivers. VR on board must be a three-phase design (9 MOSFETs) as well as there being three drivers available.

As the PWM IC is underneath the s428 HSF package, I cannot
get a multi meter reading with CPU and HSF in situ but can access
the MOSFET driver ICs on mobo surface.

A physical inspection of the board finds 2 of RS-232 serial TX/RX
ICs having, in part, a shiny surface - is this ok? These work
with +12V.

I find there are no open grounds on the ATX power connector with
PSU disconnected.

I find both the MOSFET drivers ICs are not getting any drive or supply voltage and hence consider as soft-start does not operate, that is, the
PWRON jumper on the front panel jumper block does not work,
the Intersil ISL6556CBC PWM IC is faulty - to be replaced.

Any advice, insight and opinions appreciated.