I am experimenting repairing a dead thinkpad x20. The machines power light flicks momentarily when the dc jack is inserted or removed. I accidentally shorted a couple of pins on this IC, and now the behaviour is much different, with lights doing funny things.
Anyhoo, the machine was dead to begin with..
I wonder if somebody could please tell me what this IC does, and how I might find a replacement to try out?
Here's a picture:
thanks, Carl
If you look closely it appears that on one side of the 'IC' the pins are all commoned on a ground plane. This implies to me it is a switching mosfet. These devices and this package style is common in laptops. I'm not sure if they are readily available, but I doubt replacing it alone will repair the laptop anyway.
Dave
Did you rule out an AC adaptor fault? Measuring its voltage off load is no use.
There may be more extensive damage now. If the screen is good I'd look on eBay for a working X20 with a cracked screen.
Dave
I am experimenting repairing a dead thinkpad x20. The machines power light flicks momentarily when the dc jack is inserted or removed. I accidentally shorted a couple of pins on this IC, and now the behaviour is much different, with lights doing funny things.
-------------------------------------------------------------------------------------------------------------- What the flying f*ck are you on about?
It's a mosfet switcher that provides 5 volts for the usb port. Digikey in the United States sells these. Chuck
There are several X20 motherboards on ebay right now. One is bad, but might be used as a parts source. If it was my laptop, I'd just buy a working one from ebay. The chances of repairing a laptop motherboard are slim to none unless you know exactly what's wrong with it. Andy Cuffe
snipped-for-privacy@gmail.com
On Thu, 16 Feb 2006 10:34:16 -0000, "carl0s" put finger to keyboard and composed:
Siliconix Si4435 P-Channel 30-V (D-S) MOSFET:
- Franc Zabkar
Thanks everybody, your help is very much appreciated. Thanks for the eBay pointer. I have just purchased a replacement board for £43 including delivery. Out of interest, is this MOSFET for the USB port then or something else?
On Sat, 18 Feb 2006 11:25:08 -0000, "carl0s" put finger to keyboard and composed:
AFAICT, you have two SMPS circuits in the photo. One uses a low power MOSFET (Si4435), the other uses a higher power MOSFET (SUD50N03-10). If I'm right, then there should be two PWM controller ICs nearby. You can determine the output voltage of each circuit by inspecting the values of the resistors around the PWM controller IC's error amp pins. A USB port requires +5V, while the mainboard may run on 3.3V. If you need more assistance in this area, then a larger photo might help.
- Franc Zabkar
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