1 Mar
2006
1 Mar
'06
1:07 p.m.
Does anyone have information on the TI Travelmate LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
TIA
John
1 Mar
1 Mar
1:37 p.m.
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
Cheers,
Chuck
2:59 p.m.
Chuck Guzis wrote:
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
I haven't opened it up yet but there is a 9 pin jack on the
side, maybe a serial port. It also has a modular connector
which may be a modem connection. The other side has a large
connector behind a hinged cover that looks like it may be a bus
connection for expantion or connection to some special
equipment.
John
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
Cheers,
Chuck 
5:26 p.m.
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
While this is normally reliable, be warned it doesn't _always_ work. The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony
6:07 p.m.
Tony Duell wrote:
I have raised the cover to look at the LCD and keyboard, checked
that the battery compartment doesn't have any battery contacts
in it and that it has three diffrent connectors for io and maybe
a buss extension. I haven't had time to open the case or
otherwise check anything out. As I said, a quick Google didn't
turn up anything as a starting point.
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
While this is normally reliable, be warned it doesn't _always_ work. The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony 
6:09 p.m.
John C. Ellingboe wrote:
Tony Duell wrote:
I have raised the cover to look at the LCD and keyboard, checked
that the battery compartment doesn't have any battery contacts
in it and that it has three diffrent connectors for io and maybe
a buss extension. I haven't had time to open the case or
otherwise check anything out. As I said, a quick Google didn't
turn up anything as a starting point.
I have an LT220 I can check tomorrow.
--
Eric Dittman
dittman at dittman.net
On
3/1/2006 at 3:07 PM John C. Ellingboe wrote:
While this is normally reliable, be warned it doesn't _always_
work. The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O
connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply. Last resort is popping the box open and checking
the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony
6:30 p.m.
Eric Dittman wrote:
John C. Ellingboe wrote:
I would appreciate it Eric. It looks like it might be a useful
serial terminal if my guess is correct. It has a fairly small
footprint for space limited work areas. I'm sure the small LCD
has a very limited display also.
John
Tony Duell wrote:
I have raised the cover to look at the LCD and keyboard, checked
that the battery compartment doesn't have any battery contacts
in it and that it has three diffrent connectors for io and maybe
a buss extension. I haven't had time to open the case or
otherwise check anything out. As I said, a quick Google didn't
turn up anything as a starting point.
I have an LT220 I can check tomorrow. On
3/1/2006 at 3:07 PM John C. Ellingboe wrote:
> Does anyone have information on the TI Travelmate LT220/V. A
> quick Google didn't turn up anything of value.
>
> I have acquired one with a pile of other items and have no idea
> how useful it might be. The power source, 18V DC did not come
> with it and there is no indication as to whether the center pin
> of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
While this is normally reliable, be warned it doesn't _always_
work. The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Last resort is popping the box open and checking
the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony
6:21 p.m.
"John C. Ellingboe" wrote:Tony Duell wrote:
I have raised the cover to look at the LCD and keyboard, checked
that the battery compartment doesn't have any battery contacts
in it and that it has three diffrent connectors for io and maybe
a buss extension. I haven't had time to open the case or
otherwise check anything out. As I said, a quick Google didn't
turn up anything as a starting point.
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
While this is normally reliable, be warned it doesn't _always_ work. The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony 
6:37 p.m.
According to this page, <URL:
http://www.pchub.com/uph/catf/BigPicture.aspx?iid=17639&PhotPath=632421…
, it is indeed center positive.
"ZVC36-18-D4" appears to be the
model number for the brick.
--jc
John C. Ellingboe wrote:
"John C. Ellingboe" wrote:Tony Duell wrote:
I have raised the cover to look at the LCD and keyboard, checked
that the battery compartment doesn't have any battery contacts
in it and that it has three diffrent connectors for io and maybe
a buss extension. I haven't had time to open the case or
otherwise check anything out. As I said, a quick Google didn't
turn up anything as a starting point.
On 3/1/2006 at 3:07 PM John C. Ellingboe wrote:
While this is normally reliable, be warned it doesn't _always_ work.
The
HP48 calculator has the signal ground pin of the (minimal) serial port
connected to the +ve supply line. There's an internal voltage converter
which doubles the logic supply, the transmit data pin swings between
this doubled supply voltage an logic ground, so about -5V to +5V wrt the
logic +ve line which is the RS232 signal ground.
Does anyone have information on the TI Travelmate
LT220/V. A
quick Google didn't turn up anything of value.
I have acquired one with a pile of other items and have no idea
how useful it might be. The power source, 18V DC did not come
with it and there is no indication as to whether the center pin
of the power connector is the positive connection or not.
Any external I/O connectors on it? Things like parallel port
connections
will usually have their ground/return pins conected to the - side of the
power supply.
Last resort is popping the box open and checking
the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
-tony
6:43 p.m.
J.C. Wren wrote:
According to this page, <URL:
http://www.pchub.com/uph/catf/BigPicture.aspx?iid=17639&PhotPath=632421…
That's not the same adapter as the one that came with my LT220.
--
Eric Dittman
dittman at dittman.net
, it is indeed center positive.
"ZVC36-18-D4" appears to be the
model number for the brick.
6:48 p.m.
"J.C. Wren" wrote:
According to this page, <URL:
http://www.pchub.com/uph/catf/BigPicture.aspx?iid=17639&PhotPath=632421…
Snip
Thanks JC. That is the way most of them are polarized but I
have seen enough of the others to make me leery of guessing.
That may be the brick that they used but this thing only draws
.5 amp per the sticker. Maybe other options would up the draw
and they didn't want to have a bunch of different power modules
for them.
, it is indeed center positive.
"ZVC36-18-D4" appears to be the
model number for the brick.
--jc
6:12 p.m.
On 3/2/2006 at 1:26 AM ard at p850ug1.demon.co.uk wrote:
If this were a desktop system, I'd go for the screwdriver first. However,
on portable systems, reassembly can sometimes get a little involved--at
least for my "all thumbs" hands!
Let's not forget that the original poster knows that the PSU puts out
+18vdc. It's EXTREMELY unlikely that the positive side of the PSU has a
direct connection with any signal pin!
Cheers,
Chuck
Last resort is
popping the box open and checking the ground plane on the
PCB or any of the ICs (if the ground plane is buried) against the
connector.
That's the one I do first. Why 'as a last resort'?
2 Mar
2 Mar
10:28 a.m.
If this were a desktop system, I'd go for the
screwdriver first. However,
on portable systems, reassembly can sometimes get a little involved--at
least for my "all thumbs" hands!
SOmetime I forget that not everyone had a mis-spent childhood
re-assuembly clocks and ASR33s :-)
Let's not forget that the original poster knows
that the PSU puts out
+18vdc. It's EXTREMELY unlikely that the positive side of the PSU has a
direct connection with any signal pin!
I'ev got at least one cheap serial printer where the +ve side of the PSU
(about 10V regulated) is connected to the +5V line. There's a 7905
regulator, the output of which is the logic ground line. Then the
unregulated input formes a -5V-ish line for the (discrete transistor)
RS232 driver.
It's unlikely a computer would do the same thing, and it's unlikely that
you'd find the +5V line on a normal serial or parallel connector.
I would bet a sizeable amount that if yo u can find one side of the power
connector connected to a pin you know to be ground (e.g. pin 7 on a DB25
RS232 port) then that is the -ve side of the power connector.
-tony
11 a.m.
On 3/2/2006 at 6:28 PM ard at p850ug1.demon.co.uk wrote:
SOmetime I forget that not everyone had a mis-spent
childhood
re-assuembly clocks and ASR33s :-)
Oh, my childhood was misspent, alright. But "disassembling" things, not
reassembling them. "Why are you going to give him that? All he'll do is
take it apart."
Cheers,
Chuck
1:32 p.m.
In message <200603021100300265.185091B7 at 10.0.0.252>
"Chuck Guzis" <cclist at sydex.com> wrote:
Oh, my childhood was misspent, alright. But
"disassembling" things, not
reassembling them. "Why are you going to give him that? All he'll do is
take it apart."
Mine was much the same. Only with a lot more "WHAT THE HELL DID YOU DO TO MY
<x>?!" where <x> = "Atari 2600", "tape recorder",
"CD player".....
Now I've moved on to modding Linksys NSLU2s into multifunction network
devices. I've got one sitting here that's getting ECIADSL installed on it.
The intention is to use it to replace the ageing, power-hungry PC server.
"Energy efficiency" is a great excuse for spending money. Well, that and
I've
always wanted a server that could (theoretically at least) be run off a
couple of solar panels.
--
Phil. | Kitsune: Acorn RiscPC SA202 64M+6G ViewFinder
philpem at dsl.pipex.com | Cheetah: Athlon64 3200+ A8VDeluxeV2 512M+100G
http://www.philpem.me.uk/ | Tiger: Toshiba SatPro4600 Celeron700 256M+40G
2:20 p.m.
On 3/2/2006 at 6:28 PM ard at p850ug1.demon.co.uk wrote:
Oh I stated taking everything apart, then found it was even more fun to
get it back together again.
-tony
SOmetime I forget that not everyone had a
mis-spent childhood
re-assuembly clocks and ASR33s :-)
Oh, my childhood was misspent, alright. But "disassembling" things, not
reassembling them. "Why are you going to give him that? All he'll do is
take it apart." 
3:03 p.m.
Chuck Guzis wrote:
On 3/2/2006 at 6:28 PM ard at p850ug1.demon.co.uk
wrote:
<looks around>
Was this supposed to have _changed_ at some point?
Doc
SOmetime I forget that not everyone had a
mis-spent childhood
re-assuembly clocks and ASR33s :-)
Oh, my childhood was misspent, alright. But "disassembling" things, not
reassembling them. "Why are you going to give him that? All he'll do is
take it apart."
4:59 p.m.
Oh, my
childhood was misspent, alright. But "disassembling" things, not
reassembling them. "Why are you going to give him that? All he'll do is
take it apart."
<looks around>
Was this supposed to have _changed_ at some point?
6870
days inactive
6871
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17 comments
7 participants
participants (7)
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ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
dittman＠dittman.net -
doc＠mdrconsult.com -
jcwren＠jcwren.com -
john＠guntersville.net -
philpem＠dsl.pipex.com