On 07/02/2015 12:08, Dave Plowman (News) wrote:
Is definitely my week for computer related problems. Latest one is the KVM
switch.

It's an Aten DVI/PS2 unit which cost quite a bit and looks well made -
it's in a steel case.

Symptoms are it no longer works with only one computer switched on. Boot
the second one and things do eventually all work. But the impression is it
will eventually fail.

So on the principle it is usually a power supply fault I removed it and
measured its incoming voltage under load on the bench - it uses a wall
wart to provide the DC.

Measured at just over 4v.

Wall wart says 5.3v and 2.4 amps, and by the weight/size is an SMPS.

Using my bench top 5v 3 amp supply it works normally.

A new wall wart from Aten is 35 quid plus. ;-)

How about a tenner from Rapid? Or probably cheaper still on eBay -
though you might have to change the connector to match polarity and
diameter of the KVM socket. My latest KVM is USB powered by the PCs that
it serves and as such requires no extra mains.

http://www.rapidonline.com/Electrica...V-2-5A-85-2940

One feeble old PC isn't very keen on driving it on its own.

Anyone know where I can buy a suitable one at a sensible price? It doesn't
have to be a wall wart.

Or I suppose I could just make a linear one?

Not worth the effort a linear one tends to run a bit too warm for
continuous use and life is too short to DIY wall warts. Mending them is
possible if you can get into them and safely reseal again afterwards.

Dessicated high ripple smoothing capacitor would be my guess.

--
Regards,
Martin Brown

Martin Brown wrote:

My latest KVM is USB powered by the PCs that
it serves and as such requires no extra mains.

Quite a few of the PS/2 ones are too.

On 09/02/2015 09:05, Andy Burns wrote:
Martin Brown wrote:

My latest KVM is USB powered by the PCs that
it serves and as such requires no extra mains.

Quite a few of the PS/2 ones are too.

That really does tend to be a bit hit and miss with some PCs unable to
source enough current to make the KVM behave itself. Bit pot luck...

--
Regards,
Martin Brown

On Mon, 09 Feb 2015 09:01:54 +0000, Martin Brown wrote:

How about a tenner from Rapid? Or probably cheaper still on eBay -
though you might have to change the connector to match polarity and
diameter of the KVM socket. My latest KVM is USB powered by the PCs that
it serves and as such requires no extra mains.

All of my Aten units are powered by their PCs.

Not worth the effort a linear one tends to run a bit too warm for
continuous use and life is too short to DIY wall warts. Mending them is
possible if you can get into them and safely reseal again afterwards.

Or get an empty wall wart case...I have done that a couple of times.

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In article ,
Martin Brown wrote:
A new wall wart from Aten is 35 quid plus. ;-)

How about a tenner from Rapid?

Actually over 16 quid delivered - plus a mains lead.

Or probably cheaper still on eBay -
though you might have to change the connector to match polarity and
diameter of the KVM socket. My latest KVM is USB powered by the PCs that
it serves and as such requires no extra mains.

I'd guess that this is a DVI KVM makes the difference - digits tend to
take more current. And of course it's PS2 - dunno how much spare current
they can supply.

http://www.rapidonline.com/Electrica...V-2-5A-85-2940


One feeble old PC isn't very keen on driving it on its own.

Anyone know where I can buy a suitable one at a sensible price? It
doesn't have to be a wall wart.

Or I suppose I could just make a linear one?

Not worth the effort a linear one tends to run a bit too warm for
continuous use and life is too short to DIY wall warts. Mending them is
possible if you can get into them and safely reseal again afterwards.

I'd only make a linear one if I had all the bits lying around - which I
do. Obviously with a suitable heatsink on the reg.

Dessicated high ripple smoothing capacitor would be my guess.

Good guess - it is just that.

--
*Proofread carefully to see if you any words out or mispeld something *

Dave Plowman London SW
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