"zirath" wrote in message
news:OAwLj.5472$XC1.1103@trndny08...
Tim wrote:
In article xTkLj.3775$bQ1.832@trndny09, says...
Arfa Daily wrote:
"zirath" wrote in message
news:0f2Hj.7616$Yy2.1091@trndny04...
We recently got a gateway fpd1520 (15" lcd flatscreen) monitor from
ebay. It didn't have a power cord. It says it's a 12v dc 2.5a but it
doesn't give the polarity. A person from gateway said he thought it
wouldn't hurt the monitor if it got plugged in backwards but I'd
rather not try it.

Would appreciate any help.
If it has got any external metal parts such as RCA (phono) connector
outers, BNC connector outers, 'D' connector surround etc, or possibly
screws for a stand, as these often go right through the plastic case,
and into the internal chassis, then try measuring from any such metal
to each of the DC power input connector's terminals in turn, using an
ohm meter. Chances are you'll find a direct connection, and that will
be your DC ground ( "-" ) connection. The other will then be the "+".
Assuming that it's a 'standard' co-axial DC connector, on most modern
equipment, 'pin' is "+" and side contact is "-" although that's not
cast in stone. Be aware when you are obtaining a replacement PSU, that
the plug is often a slightly abnormal size, being a little larger than
those you typically find on 'general' power supplies. Also, make sure
that you get one well rated for the job, as these monitors do draw
quite a lot of current, and may well surge up close to the quoted 2.5
amps at startup, as the LCD backlights first fire up before settling to
their run current.

As to whether it would be safe to reverse connect it, I wouldn't like
to say. Some equipment is perfectly well protected against such
'consumer antics', but it is by no means guaranteed, and if it is not
adequately protected, the result is often an item that's fried beyond
repair, for no other reason than unobtainable power supply devices, as
many previous posts on this subject over the years, will attest ...

Arfa

The ohm meter showed something like a capacitor on the center pin (it
went to 0 and then back towards the center). The side showed no
resistance.

The monitor went on briefly and then went black when plugged into the
power. Seems like it's a dud. Not sure if it's worth trying to repair it
or just return it.


Is there no little pic of the connector around where it give the info
about power? Usually there is a universal icon used that indicates
polarity, kinda like a big C around a dot. Most, but not all, coaxial
power connectors have the minus side on the outside, that way if it
touches a grounded side, it will not destroy the adapter. If the adaptor
cannot start the monitor because it is not powerful enough, it will
sometimes just flash the backlight then go off.

- Tim -

The adapter symbol shows center + and side -. It is labeled 12vdc 4a. The
monitor is 12vdc 2.5a so the adapter should have enough power.

Before condemning the monitor, I would feel inclined to just try a different
power supply (bearing in mind that the one you are using now is not an
'original'). The reason that I say this is that there can be quite a high
initial pulse of current demand, as the backlights strike, and it just might
be that the power supply sags a little when hit with this, even though it
*says* that it is rated for 4A ...

Arfa