Clarification of Answer by
sublime1-ga
on
06 Nov 2005 12:42 PST
vincimus...
To respond to your questions:
"Just to clarify, the inverter doesn't seem to have a amps rating, just
115VAC 60HZ and 140 W cont."
Thanks for the feedback. Since it's rated at 140W, and the unit that
was recommended for your laptop on AtBatt is 150W, I'm still inclined
to believe it's safe, given the precautions I mentioned earlier.
"The T42 power supply doesn't mention watts, just 16V and 4.5 A."
"A power supply recommnded by IBM shows 75 W"
16V x 4.5A = 72W, so that's the same ballpark. And given that
the laptop is probably using less than that at any given time,
the 140W inverter seems to have a comfortable margin, as I
suggested.
"Anyway, my sense is that I could probably use the inverter, but I'd be
better off trying to find a tip for the DC power supply I have (don't
know quite where) or buying a new one. (I do have a spare DC adapter
rated at 3.5 A, but it's shrink wrapped on my boat!)"
Latter point first: the adapter with the higher amperage rating
is preferable. Just because the adapter is rated to handle a
higher amperage doesn't mean it will cause a higher amperage to
be used. The notebook will draw only what current it needs.
As for the tip, it's hard to know for sure without seeing it,
and being able to determine whether it's a unique design that
is proprietary for IBM notebook power supplies, but it sounds
to me like the tip is simply the input jack, and doesn't
contain a fuse, as you thought it might, and that it simply
broke or fell apart. If it was me, and I thought this might
be a standard jack, I would go to Radio Shack and see if I
could find a replacement jack with a tip that would fit in
the laptop. I would then cut off the old jack from the
DC adapter and connect the wires to the new one.
It might even be necessary to buy a similar power adapter
in order to get the jack that comes with it. If that were
the case, I would still do the above, using the adapter
that was designed for the laptop, and just using the new
plug or jack.
If this is the type of jack I'm thinking of, there are
two contacts which deliver the voltage. The tip is a
hollow tube, essentially, with a silvery contact on the
outside which is one of the contacts. Inside the tube
is another metal contact, providing the other polarity.
It sounds like the outside silvery contact just broke
off or fell off of your original jack, and that you
might be able to replace it with a jack of the same
size, though, again, I'm not sure how standardized
these types of jacks are. If you do go that route,
you would need to make sure that the polarity is
correct when you connect the wires to the contacts.
I'm not sure whether the outer contact should be
negative or positive, but it would be critical that
you make this determination before replacing the
jack. Perhaps the staff at Radio Shack can assist
you by examining the wiring and measuring the voltage
and polarity on your old adapter.
You might even find that Radio Shack sells a generic
power adapter rated at 16V. If it was also rated at
4.5Amps or higher, and had the correct jack, you
could probably use that, though, again, power adapters
designed specifically for your laptop would likely
include circuit designs to provide a more stable
voltage.
That's about all I can think to add, but if you have
further questions or comments, feel free to post them.
sublime1-ga
