Re: Sony MBX-197 power circuit, help me think it through

Apologies: To clarify the CPU fan problem. I have tested the fans with a scope and all signals are correct on another MB. On the MBX-197 both fans turn on and run full tilt after 3 seconds of applying power and the VAIO logo displays on the LCD. (indicating the PWM line and 5v supply is working on the main board) but somewhere on the tachometer line or the corresponding sensor IC(s) something is either being pulled down or is open circuit. (haven't found it/them yet, still tracing down the IC)

This causes the...

Re: Sony MBX-197 power circuit, help me think it through

Hi Runderwo, I have a MBX-197 (MB813MP Rev. 1.2) from a Sony Vaio All-In-One with power issues too. Bought the complete computer unit at an auction only to find it didn't come on. I found the same as you the two ADO452A's were blown and the 5R6 (5.6uH) SMD choke was fried. I had to replace the 5R6 (Rewind with 3 x strands of ECCW-0.25 aka SWG-33, 7.5 turns anti-clock wise) after frying the two brand new ADOs i had just replaced. After doing this and another set of ADOs, SHE NOW COMES ON!!! Seems it does cut out some noise...