Cisco-Linksys (lack of important details)

I have a Linksys network switch, but lost the power supply.
I have a box of 12 V DC power supplies, hoping one would fit, but on
the body of the switch the polarity is not indicated. The product
manual only shows voltage and current required, not polarity.
Pitiful to omit such basic info.
So I search eBay for 20 minutes, found a power supply that is compatible,
then find out polarity for that.

wrote:
I have a Linksys network switch, but lost the power supply.
I have a box of 12 V DC power supplies, hoping one would fit, but on
the body of the switch the polarity is not indicated. The product
manual only shows voltage and current required, not polarity.
Pitiful to omit such basic info.
So I search eBay for 20 minutes, found a power supply that is compatible,
then find out polarity for that.

You can check for screws in the "feet" of the unit, take it
apart and examine the PCB. The casing will probably be hinged
on one edge. Perhaps some capacitors next to the
power entry point, have polarity markings.

Adapters with barrel connectors, come in three kinds. AC,
regulated DC, and unregulated DC. The latter are the larger
transformer-type units. However, when there is a case marking,
there appears to be no standard way of saying whether the
power is regulated or unregulated. On the unregulated ones,
the voltage rises when the unit is quiet, and drops to the
specified level, when things like motors are operating. My
label printer, operates on D cells, or, it can use an unregulated
supply. When I connected a regulated supply, it didn't print.
Only the unregulated supply worked.

Paul

On Sun, 19 Mar 2017, wrote:

I have a Linksys network switch, but lost the power supply.
I have a box of 12 V DC power supplies, hoping one would fit, but on
the body of the switch the polarity is not indicated. The product
manual only shows voltage and current required, not polarity.
Pitiful to omit such basic info.
So I search eBay for 20 minutes, found a power supply that is compatible,
then find out polarity for that.

That's why I've started to mark the units with a marker. Often, but not
always, the AC adapter has the polarity marked. So it is useful to keep
such information with the unit. Manuals often don't indicate polarity.
Of course, if you have the AC adapter, you can measure it, and doing it at
the start means the information is available there.

I've also started using a silver Sharpie to mark the AC adapters. so I can
more easily tell which is for which.

Michael

On 3/19/2017 6:30 AM, wrote:
I have a Linksys network switch, but lost the power supply.
I have a box of 12 V DC power supplies, hoping one would fit, but on
the body of the switch the polarity is not indicated. The product
manual only shows voltage and current required, not polarity.
Pitiful to omit such basic info.
So I search eBay for 20 minutes, found a power supply that is compatible,
then find out polarity for that.

You might want to identify the model of the switch here. Someone might
have the same model and be able to answer your question after checking
what their working unit is using.