18 Feb
2004
18 Feb
'04
7:29 a.m.
Hi. i don't know if you have it already. I have one,. it is definetely 5V, however,
I dont know if the (+) is inside or outside. If you know, please let me know since i need
to plug it in too...
23 Feb
23 Feb
8 a.m.
On Wed, 18 Feb 2004, Alfredo B. Roisenzvit wrote:
Hi. i don't know if you have it already. I have
one,. it is definetely
5V, however, I dont know if the (+) is inside or outside. If you know,
please let me know since i need to plug it in too...
Hi Alfredo.
That is the big question. The center pin seems to go right into a diode,
but I can't tell what side of the diode that is. The outside conductor
goes to the ground plane, which would indicate that it is negative? So my
guess is that this is center positive?
Anyone? Anyone?
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
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8:41 a.m.
New subject: OT: Need P/S specs for Power Sentry USB hub (was OT: Need HP
Rumor has it that Vintage Computer Festival may have mentioned these words:
On Wed, 18 Feb 2004, Alfredo B. Roisenzvit wrote:
AFAIK, *almost all* wallwarts were center positive. If the outer ring is
going to the ground plane, that *should* be the clincher, but... as they
say about assuming things...
The reason for this is supposed to be that if a barrel connector is
center-negative and is grounded, if the barrel touches any part of the
circuit that's grounded (which is usually a pretty fair amount) it will
short out the PS and possibly do bad things to the circuit. The risk is
_lessened_ when the barrel is negative.
This is why I'm *always* careful with wallwarts for my Tandy Model 'T'
computers - they are barrel-positive.
HTH,
Roger "Merch" Merchberger
P.S. I'm back... either someone hates me (plausible) or the listserver
software "forgot" me (equally plausible) because I just stopped getting
posts awhile back... Xmas was quite busy for me, so I've finally found the
time to get resubbed.
--
Roger "Merch" Merchberger | JC: "Like those people in
Celeronville!"
sysadmin, Iceberg Computers | Me: "Don't you mean Silicon Valley???"
zmerch(a)30below.com | JC: "Yea, that's the place!"
| JC == Jeremy Christian
Hi. i don't know if you have it already. I
have one,. it is definetely
5V, however, I dont know if the (+) is inside or outside. If you know,
please let me know since i need to plug it in too...
Hi Alfredo.
That is the big question. The center pin seems to go right into a diode,
but I can't tell what side of the diode that is. The outside conductor
goes to the ground plane, which would indicate that it is negative? So my
guess is that this is center positive?
Anyone? Anyone? 
12:54 p.m.
New subject: OT: Need P/S specs for Power Sentry USB hub (was OT: Need
AFAIK, *almost all* wallwarts were center positive. If
the outer ring is
going to the ground plane, that *should* be the clincher, but... as they
say about assuming things...
The problem comes what that design of connector (we call it a 'coaxial DC
power connector over here') is used on a device that has internal
batteries too. Theres's a switch contact which breaks when the plug is
inserted, but that connects to the _outer_ contact of the plug. And
conventionally, that switch is connected in the +ve line. Certainly a lot
of devices over here are outer +ve...
When 2.5mm or 3.5mm hack plugs (OK, mini and submini phone plugs to you),
then it's conventional to have tip +ve. And the switch contact on those
sockets is on the tip connection.
A popular wall wart in the UK has a cross-shaped plug with the 4 arms
being a 2.5mm jack, 3.5mm jack, 2.1mm (interal) coaxial power connector
and a 2,5mm coaxial power connector. I've seen them where the tip of the
jack plugs corresponts to the outer of the power connectors. Conversely,
I've seen them where the tip of the jack plugs corresponds to the inner
of the power connectors. The only way to be sure is to check it with a meter!
The reason for this is supposed to be that if a barrel connector is
center-negative and is grounded, if the barrel touches any part of the
circuit that's grounded (which is usually a pretty fair amount) it will
short out the PS and possibly do bad things to the circuit. The risk is
_lessened_ when the barrel is negative.
Indeed. There's also a panel mount version of the connector -- I use it
quite a lot -- where the outer is connected to the panel mounting
bush/nut. That had better be at ground potential !
-tony
11:25 a.m.
On Mon, 23 Feb 2004, Vintage Computer Festival wrote:
That is the big question. The center pin seems to go
right into a diode,
but I can't tell what side of the diode that is. The outside conductor
goes to the ground plane, which would indicate that it is negative? So my
guess is that this is center positive?
Dunno if I've got the same model that you're both looking at, but the
Power Sentry USB 2.0 hub I've got on my desk here does have a 5V, .3A,
center positive wall wart.
--Ian
11:28 a.m.
On Mon, 23 Feb 2004, Ian Viemeister wrote:
On Mon, 23 Feb 2004, Vintage Computer Festival wrote:
Hooray! The amperage was the last missing piece of information.
Thanks!
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
That is the big question. The center pin seems
to go right into a diode,
but I can't tell what side of the diode that is. The outside conductor
goes to the ground plane, which would indicate that it is negative? So my
guess is that this is center positive?
Dunno if I've got the same model that you're both looking at, but the
Power Sentry USB 2.0 hub I've got on my desk here does have a 5V, .3A,
center positive wall wart.
11:47 a.m.
On Mon, 23 Feb 2004, Vintage Computer Festival wrote:
Allow me to quickly correct one error after looking more closely at the wall wart.
The INPUT side is 0.3A at 110V AC.
The OUTPUT side is 2.2A at 5V DC.
Sorry about that.
Dunno if
I've got the same model that you're both looking at, but the
Power Sentry USB 2.0 hub I've got on my desk here does have a 5V, .3A,
center positive wall wart.
Hooray! The amperage was the last missing piece of
information. Thanks!
Not a problem, it just happened to be sitting in front of me.
--Ian
12:38 p.m.
On Mon, 23 Feb 2004, Ian Viemeister wrote:
Allow me to quickly correct one error after looking
more closely at the
wall wart.
The INPUT side is 0.3A at 110V AC.
The OUTPUT side is 2.2A at 5V DC.
Sorry about that.
Thanks for the correction.
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]
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ard＠p850ug1.demon.co.uk -
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