TC1100 high pitched squeal near cpu

[JesseKnows]

Another possible source for squeals is the display inverter, but when you open the device it splits away from the motherboard and should be easy to tell.

[elleses2030]

Updates:

(To JesseKnows: The squeal does not come from the display side, it's something around the Northbridge.)

I tried an automotive stethoscope. It's pretty hard to locate the sound with or without it. When I press the end onto components, they are transmitting the sound, since they are all attached to the same board. The Northbridge is louder than the fan housing above the CPU and also louder than the NVDIA chip, but it's about the same loudness as a number of small ICs nearby, and the round component (pot/variable cap/?) near the disk connector.

Two interesting data points:

1. When I press the display toggle button (next to the power slide switch), it generates a version of the squeal, even when the computer is off. It has always caused a red light to glow, but it now causes the squeal, which still seems to be coming from down near the Northbridge chip.

2. When the computer is off and I add power from the transformer, I get a squeal about 40 seconds later.


I'm having second thoughts about buying a new motherboard. I don't know what role the transformer is playing in all of this, and if other components are messed up, a new motherboard will only be the beginning of the costs. It still boots all the way up on the Ubuntu hard drive, but the squeal makes it unacceptable.

I'm going to look at alternatives again, and may part this unit out, or put it up for adoption. It's a shame, it's in such good condition other than the squeal... More news when it happens...

[TFreeman]

My TC1100 was doing the same thing. What worked for me was disabling one of the USB hubs via the device manager. This suggestion came from "Steve" the last contributor to this discussion:

http://h30499.www3.hp.com/t5/Noteboo...in/td-p/468750

I wasn't sure which one (or all) to disable, so I plugged a thumbdrive into the one I use most often then disabled one hub in the DM. The drive kept working, but the sound was gone.

[elleses2030]

My TC1100 was doing the same thing. What worked for me was disabling one of the USB hubs via the device manager. This suggestion came from "Steve" the last contributor to this discussion: http://h30499.www3.hp.com/t5/Noteboo...in/td-p/468750 I wasn't sure which one (or all) to disable, so I plugged a thumbdrive into the one I use most often then disabled one hub in the DM. The drive kept working, but the sound was gone.

Thanks for the reply and the interesting url. The problem described is opposite from the one I'm having (I only hear the squeal when power is applied), but the suggested diagnosis matches my theory (an inverter or related part of the power management circuitry). I don't have Windows on my hard drive, so I'll have to go searching in Ubuntu for some equivalent to this USB power management setting. I still haven't found a more modern replacement (lots of yuck Intel Atom devices and some VIA Nano devices that don't seem like a decent substitute, even though they have a more sophisticated CPU).