Hi,
Just bought a new display, so I took the time to tear down my old Lenovo to see what's causing the irritating whine/squeal/buzz that's been giving me headaches.
And it appears to be coming from all 3 transformers that can be found on the PSU board(find the attached pic). Not all at once but each at it's own time depending on the display state:
T1 when the AC is plugged (probably usb hub power)
T2 when I turn on the display (CCFL backlight)
T3 when the display goes to sleep (stand by/display controller)
As i've read in a lot of threads here it's never the transformer itself causing the noise but faulty caps/diodes/resistors. My knowledge in electronics basically ends here so i was hoping for some help from experts to at least help me narrow it down or simply find the culprit. Where to look for shorts and so on.
Thanks in advance
Just bought a new display, so I took the time to tear down my old Lenovo to see what's causing the irritating whine/squeal/buzz that's been giving me headaches.
And it appears to be coming from all 3 transformers that can be found on the PSU board(find the attached pic). Not all at once but each at it's own time depending on the display state:
T1 when the AC is plugged (probably usb hub power)
T2 when I turn on the display (CCFL backlight)
T3 when the display goes to sleep (stand by/display controller)
As i've read in a lot of threads here it's never the transformer itself causing the noise but faulty caps/diodes/resistors. My knowledge in electronics basically ends here so i was hoping for some help from experts to at least help me narrow it down or simply find the culprit. Where to look for shorts and so on.
Thanks in advance
Attached Files
