Date: Thu, 3 Mar 2005 17:53:28 -0800 (PST)
From: Matt Hanson <[EMAIL PROTECTED]>
Subject: RE: [LIB] Dead L110
I'll rename this thread back to the more appropriate"[LIB] Dead L110"
--- [EMAIL PROTECTED] wrote:
>
> I have an old L70 that I have never used and never opened up. My main
> Libby is the L100, which I bought new.
> Speaking in generalities about fuses, since I have not seen one in
> either machine, here is what a typical design engineer would do:
> 1. If a fuse was required to protect the device from catastrophic
> failure, he would include a fuse that could be replaced easily.
> ("Easily" could mean by a Toshiba repair person, or by the customer -
> but it would still be accessible by someone.)
> 2. In rare instances, he could put in what is called a "fusible link".
> This is usually thermally tripped, and functions exactly as a fuse that
> was tripped due to over current. These links are usually soldered in and
> not meant for anyone but repair personnel to repair.
> 3. Fuses come in limited sizes / shapes, but they would not be confused
> with capacitors or resistors.
> 4. A fuse that prevents the power from being applied to the computer is
> probably located very close to the connector where the power supply
> comes in to the computer.
>
> When you see large quantities of the same shape device, it is not a
> fuse. Fuses are a last resort to protect the circuit - it is assumed the
> problem causing the fuse to "blow" will be obvious to the person trying
> to repair it, otherwise just putting in a new fuse would cause the new
> fuse to also "blow".
This all sounds very logical Dick. Thanks for the run-down.
> I will see if I can open up my L100 and tell you if there are any fuses
> in it.
Thanks Dick.
I went over my 110 board for quite a while last night, and couldn't find
anything that looked uniquely like it may be a fuse. I think Neil was
lucky that the 70 had a rather large fuse in comparision to the other
components on the board. And it was sitting right next to the input power
plug. So finding an open circuit across it was probably a dead giveaway.
That fuse powered the screen, and I guess I was pretty lucky that Neil had
dealt with the exact same issue.
Now the issue with this 110 MB is that >nothing< works when the system is
powered up. Or nothing that I can detect besides 3 out of 4 LEDs lighting,
and the HDD spinning. So there may be no dead fuse to find.
I took a few photos of the 70 & 110 MBs that I could blow up on the desktop
screen and look over carefully. What I thought may have been solder
connections indicating overheating due to brownish discoloration turned out
to be solder resin residual most probably from the components being
manually soldered to the board during manufacturing. Things like large
capacitors, the IR unit, etc.
Matt
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