Worrying 'fizzing' sound from my Compaq n410c

Hi, guys.

I'm new to these forums, but have some useful amatuer experience working on laptops. I'm having a problem with this one though. My old Compaq n410c started making a sort of electrical fizzing noise a while ago, and I can't seem to nail it down.

On another forum, someone said their problem in this respect turned out to be a loose CPU heatsink. Thinking it might be this, I diassembled the laptop, removed the heatsink, and cleaned off the old TIM, replacing it with Antec silver-loaded TIM. No difference (and anyway, the old TIM looked fine).

I'm wondering if it's still CPU-related, as it gets worse when, for example, I scroll down a page in my browser, and then quietens slightly as soon as I stop scrolling. I had also wondered if it might be a slightly dodgy DC jack, as moving the plug (on the non-original PSU) in the socket seems to have some impact on the sound, though there's none of the intermittency associated with loose jack soldering. I cleaned the battery/mains leaf switch in the jack with contact cleaner too, again without improvement.

I can't see anything obviously dodgy on the mobo, but could it be a bad cap or a dry joint?

I'd like to keep the laptop running reliably (it works fine despite the fizzing) as it's a handy little machine to have.

Cheers, Jon.

 

Another forum member mentioned a similar noise that changed as they scrolled down the pages as you have mentioned, dont know where it is though.

Also a thing called cpu whine is another noise.

 

Mmmm, thanks for the pointer - I'll do a more in-depth search and see what that turns up.

BTW, I should have mentioned that the laptop has a PIIIm running at the default 1.2GHz speed. I'm using a non-original PSU - it's a Maplin 120W multi-voltage unit set to 18VDC. The n410c is specced to run on 18.5VDC, but I've used it since I got it about a year ago with no problems until the fizzing started.

Cheers, Jon.

 

It just sounds like an old notebook creaking with age, I though it was an new notebook you were talking about.

 

I read up about the CPU whine, and it's definitely not that. It's not a mechanical creaking either - the laptop makes the noise even when I'm not touching it, and it's resting on a flat, stable surface. This is a kind of fizzing noise I've occasionally heard in other electronics - in a power supply, it would suggest to me maybe a dirty contact or something about to fry.

Cheers, Jon.

 

Does this work even on a CPU which isn't switching power state? I've got the power management settings on Desktop/Always on, to stop the CPU throttling - it runs continuously at 1.2GHz (and it's a 1.2GHz PIIIm).