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? US Robotics Sportster 28,800 Fax modem - PSU requirements.

D

David Chapman

Jan 1, 1970
0
I have mislaid the power supply for a US Robotics Sportster 28,800 Fax
Modem (with V34 and V32bis) which I would like to use. This modem
lights up and *appears* to work with a supply of 9 volts DC, drawing
around 200mA, but I'm not yet entirely convinced that it is performing
correctly.

I did some Google searching and haven't managed to find a manual or
any information about the particular unit that I have, but I did see a
similar modem mentioned which requires 9 volt AC to power it. I haven't
yet attempted feeding my modem with AC because I don't want to risk
damaging it..

Can anyone in this NG tell me what the correct voltage should be, and
if it should be AC or DC?
Is there anywhere on the 'net where I might find a User Manual for
this modem? I've searched for one, so far without any success.

Many thanks,

- Dave.
 
S

Sheila

Jan 1, 1970
0
David Chapman said:
I have mislaid the power supply for a US Robotics Sportster 28,800 Fax
Modem (with V34 and V32bis) which I would like to use. This modem
lights up and *appears* to work with a supply of 9 volts DC, drawing
around 200mA, but I'm not yet entirely convinced that it is performing
correctly.

I did some Google searching and haven't managed to find a manual or
any information about the particular unit that I have, but I did see a
similar modem mentioned which requires 9 volt AC to power it. I haven't
yet attempted feeding my modem with AC because I don't want to risk
damaging it..

Can anyone in this NG tell me what the correct voltage should be, and
if it should be AC or DC?
Is there anywhere on the 'net where I might find a User Manual for
this modem? I've searched for one, so far without any success.

Many thanks,

- Dave.

Have you tried contacting a support technician
http://www.usr-emea.com/support/s-email-techie-unkg.asp?loc=unkg

Alternatively, search for the 33.6 version manual - which was the same
hardware with a firmware update.

Good Luck, Sheila
 
C

Cydrome Leader

Jan 1, 1970
0
In sci.electronics.equipment David Chapman said:
I have mislaid the power supply for a US Robotics Sportster 28,800 Fax
Modem (with V34 and V32bis) which I would like to use. This modem
lights up and *appears* to work with a supply of 9 volts DC, drawing
around 200mA, but I'm not yet entirely convinced that it is performing
correctly.

I did some Google searching and haven't managed to find a manual or
any information about the particular unit that I have, but I did see a
similar modem mentioned which requires 9 volt AC to power it. I haven't
yet attempted feeding my modem with AC because I don't want to risk
damaging it..

Can anyone in this NG tell me what the correct voltage should be, and
if it should be AC or DC?
Is there anywhere on the 'net where I might find a User Manual for
this modem? I've searched for one, so far without any success.

Many thanks,

- Dave.

I can check when I get home. I have boxes of those things.
 
M

Mike S.

Jan 1, 1970
0
I have mislaid the power supply for a US Robotics Sportster 28,800 Fax
Modem (with V34 and V32bis) which I would like to use. This modem
lights up and *appears* to work with a supply of 9 volts DC, drawing
around 200mA, but I'm not yet entirely convinced that it is performing
correctly.

I did some Google searching and haven't managed to find a manual or
any information about the particular unit that I have, but I did see a
similar modem mentioned which requires 9 volt AC to power it. I haven't
yet attempted feeding my modem with AC because I don't want to risk
damaging it..

Can anyone in this NG tell me what the correct voltage should be, and
if it should be AC or DC?
Is there anywhere on the 'net where I might find a User Manual for
this modem? I've searched for one, so far without any success.

Many thanks,

- Dave.

Only data I have is for US models, but perhaps you'll find something of
use here. Since there have been 18.3 gazillion different "sportster"
models, it would help if you posted the exact part number.



USR Part Number: Voltage: Model Number(s)

1.015.090-B: (Input 120VAC, 60Hz) (Output: 9.2 vac@533mA):
00021800 00021900 00026100 00026400
00026500 00026501 00026502 00026600
00026601 00026700 00026701 00026702
00026800 00026801 00026802 00026805
00026806 00026900 00026901 00026902
00026905 00027800 00092200

1.015.1202-B: (Input 120VAC, 60Hz) (Output: 20vac @750mA):
00027900 00074500 00074600 00074700
00074800 00083900 00083901 00083902
00084100 00114100 00117200 00126500
00126501 00126502

1.015.1286: (Input 120VAC, 60Hz, 16Watts) (Output 9VAC, 1000mA):
00083903 00083905 00083907 00083908
00083909 00084000 00084001 00084002
00084003 00084004 00084005 00126502
00126504 00126505 00178400 00178600
00178602 00178900 00178902 00564100
00568400 00568600 00568602 00568603
00568900 00568902 00568903

1.015.1443-00: (Input: 120v AC, 60 Hz, 21 watts) (Output: 9 volts AC, 1500
mA):
00560500
 
D

David Chapman

Jan 1, 1970
0
Mike S. said:
Only data I have is for US models, but perhaps you'll find something of
use here. Since there have been 18.3 gazillion different "sportster"
models, it would help if you posted the exact part number.


Very many thanks for all of the contributions made in response to my
posting.

I have just sent a query to the support technicians at US Robotics and
am awaiting a reply.

I'm not sure of the exact model number - printed on the actual case
is a number which is similar, but different, to the list of models shown
above - it reads 1.020.139-B. There is also a white adhesive label on
the underside which says: CJE-0268 followed by the long number
0108390014294363,

From the above information it appears that the unit does require an AC
supply, but I'll wait a day or so to see if US Robotics reply before I
try experimenting with the supply voltage.

Thanks again - Dave
 
S

Steve Terry

Jan 1, 1970
0
David Chapman said:
I have mislaid the power supply for a US Robotics Sportster 28,800 Fax
Modem (with V34 and V32bis) which I would like to use. This modem
lights up and *appears* to work with a supply of 9 volts DC, drawing
around 200mA, but I'm not yet entirely convinced that it is performing
correctly.

I did some Google searching and haven't managed to find a manual or
any information about the particular unit that I have, but I did see a
similar modem mentioned which requires 9 volt AC to power it. I haven't
yet attempted feeding my modem with AC because I don't want to risk
damaging it..
If it is fed with AC it'll be to a rectifier and regulator circuit turning
it
into DC, so be on the safe side and feed it with DC anyway.

Run it on 12v DC, it's likely the regulators will be able to dissipate it
if it is excessive voltage.

Steve Terry
 
T

tm

Jan 1, 1970
0
Steve Terry said:
If it is fed with AC it'll be to a rectifier and regulator circuit turning
it
into DC, so be on the safe side and feed it with DC anyway.

Run it on 12v DC, it's likely the regulators will be able to dissipate it
if it is excessive voltage.
If it needs AC, then it is most likely generating plus and minus dc voltages
inside. Since it is a modem, and has rs232, it would need + and - voltages.

If you feed it dc only, you will only have one of the supplies in the unit.


Try a 9 volt ac wart.
 
W

Woody

Jan 1, 1970
0
tm said:
If it needs AC, then it is most likely generating plus and
minus dc voltages
inside. Since it is a modem, and has rs232, it would need +
and - voltages.

If you feed it dc only, you will only have one of the supplies
in the unit.


Try a 9 volt ac wart.



We (still) use the USR Message Modem and that needs 18Vac. My
Googling indicates 9Vac 400mA
 
I

ian field

Jan 1, 1970
0
Woody said:
We (still) use the USR Message Modem and that needs 18Vac. My Googling
indicates 9Vac 400mA


IIRC the most common type is 13VAC.

Bear in mind that if it connects to the PC via RS232, it must be capable of
generating plus and minus 12v rails.
 
T

Theo Markettos

Jan 1, 1970
0
In uk.telecom Woody said:
We (still) use the USR Message Modem and that needs 18Vac. My
Googling indicates 9Vac 400mA

9V AC sounds about right for the Sportster 14400 (very similar). It's
definitely an AC supply and I'm fairly sure it's 9V. I think it may be a
bit more than 400mA, BICBW.

Theo
 
B

Bob Eager

Jan 1, 1970
0
IIRC the most common type is 13VAC.

Bear in mind that if it connects to the PC via RS232, it must be capable
of generating plus and minus 12v rails.

I built a board here that runs off 5V. A MAX232 driver/charge pump drives
the serial line fine.
 
I

ian field

Jan 1, 1970
0
Bob Eager said:
I built a board here that runs off 5V. A MAX232 driver/charge pump drives
the serial line fine.


Its the darndest thing tho', I've never yet seen a MAX232 in any of the
modems I've had apart.
 
B

Bob Eager

Jan 1, 1970
0
Its the darndest thing tho', I've never yet seen a MAX232 in any of the
modems I've had apart.

Should have made it clear, mine wasn't a modem...it was a clone of a
PDP-8....!
 
I

ian field

Jan 1, 1970
0
Bob Eager said:
Should have made it clear, mine wasn't a modem...it was a clone of a
PDP-8....!


In which case - what the hells it got to do with the OP's question.
 
B

Bob Eager

Jan 1, 1970
0
In which case - what the hells it got to do with the OP's question.

It shows that a 5V supply could be sufficient, depending on circuitry. Do
keep up.
 
C

Cydrome Leader

Jan 1, 1970
0
In sci.electronics.equipment Cydrome Leader said:
I can check when I get home. I have boxes of those things.

an original USR power adapter P/N 1.015.1286 = 9VAC 1000mA

that's the same power adapter for any of the 28.8 and 33.6 modems I have
here.
 
D

David Chapman

Jan 1, 1970
0
Sheila said:
Have you tried contacting a support technician
http://www.usr-emea.com/support/s-email-techie-unkg.asp?loc=unkg

Alternatively, search for the 33.6 version manual - which was the same
hardware with a firmware update.

Good Luck, Sheila
Well, here's the definitive response that I've now received from US
Robotics:-

"Based on the FCC number CJE-0268 that you gave us is from the model
number USR0839. If you have this model number then the specification of
the power supply is 20V AC .5A."

So, the correct voltage WAS somewhere between 9 volts DC and 20 volts
AC ;-)

And so to bed! Many thanks to all those who contributed to this
posting.

All the best - Dave
 
C

Cydrome Leader

Jan 1, 1970
0
In sci.electronics.equipment David Chapman said:
Well, here's the definitive response that I've now received from US
Robotics:-

"Based on the FCC number CJE-0268 that you gave us is from the model
number USR0839. If you have this model number then the specification of
the power supply is 20V AC .5A."

I don't believe that info at all. There's only two screws holding the
modem together so you can check the filter caps if you want.

first off, that's not the modem you have. You have a 28.8 sporters so it's
very old, and not the latest 33.6 they may be selling now which they may
have given you specs for.

none of the 28.8 or first 33.6 sportsters used 20 volt adapters. Only
couriers did.

They still make couriers but switched from AC adapters to DC switching
power supplies and changed the power connector several times.
 
I

ian field

Jan 1, 1970
0
Bob Eager said:
It shows that a 5V supply could be sufficient, depending on circuitry. Do
keep up.

Why would I want to keep up with an irrelevance.
 
D

David Chapman

Jan 1, 1970
0
Cydrome Leader said:
I don't believe that info at all. There's only two screws holding the
modem together so you can check the filter caps if you want.

first off, that's not the modem you have. You have a 28.8 sporters so it's
very old, and not the latest 33.6 they may be selling now which they may
have given you specs for.

none of the 28.8 or first 33.6 sportsters used 20 volt adapters. Only
couriers did.

They still make couriers but switched from AC adapters to DC switching
power supplies and changed the power connector several times.

I can now finally put this discussion to bed since I've managed to
find the actual PSU for the USR Sportster 28,800 Fax modem.

It is marked as producing 18 volts AC at 500mA.

My thanks again to all in this NG who offered suggestions.

- Dave
 
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