KVM power supply.
 

"Mike Tomlinson" wrote in message
...
En el artículo , Dave Plowman (News)
escribió:

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. ;-)

It'll be the output cap. Crack it open (it'll almost certainly be
welded shut. You can crack the seams carefully by squeezing them in a
vice) and replace the cap.

One of the youtube teardowns shows the use of a screwdriver handle
to whack it with can be surprisingly effective in that situation.

Whether is worth farting around when 5V 3A switch
mode wall warts cost peanuts tho is another matter.

Use a good quality 105 degC replacement.
Reassemble case with superglue.

Total cost about 50p.

The caps fail due to heat build-up in the case and no ventilation.

There is going to be **** all heat in a 5V 3A switch mode wall wart.

KVM power supply.
 

In article ,
Rod Speed wrote:
It'll be the output cap. Crack it open (it'll almost certainly be
welded shut. You can crack the seams carefully by squeezing them in a
vice) and replace the cap.

One of the youtube teardowns shows the use of a screwdriver handle
to whack it with can be surprisingly effective in that situation.


This one was so well welded or glued that nothing would prise it apart.
And even after cutting it open on three sides, the fourth ripped rather
than the joint giving way.

--
*I don't have a solution, but I admire your problem. *

Dave Plowman London SW
To e-mail, change noise into sound.

KVM power supply.
 

On Sun, 08 Feb 2015 00:18:25 +0000, Dave Plowman (News) wrote:

In article ,
Rod Speed wrote:
It'll be the output cap. Crack it open (it'll almost certainly be
welded shut. You can crack the seams carefully by squeezing them in
a vice) and replace the cap.

One of the youtube teardowns shows the use of a screwdriver handle to
whack it with can be surprisingly effective in that situation.


This one was so well welded or glued that nothing would prise it apart.
And even after cutting it open on three sides, the fourth ripped rather
than the joint giving way.

Angle grinder? Or Dremel?



--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £30a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

KVM power supply.
 

"Dave Plowman (News)" wrote in message
...
In article ,
Rod Speed wrote:
It'll be the output cap. Crack it open (it'll almost certainly be
welded shut. You can crack the seams carefully by squeezing them in a
vice) and replace the cap.

One of the youtube teardowns shows the use of a screwdriver handle
to whack it with can be surprisingly effective in that situation.


This one was so well welded or glued that nothing would prise it apart.
And even after cutting it open on three sides, the fourth ripped rather
than the joint giving way.

Yeah, it certainly doesn’t work with them all.

KVM power supply.
 

In article ,
Bob Eager writes:
On Sun, 08 Feb 2015 00:18:25 +0000, Dave Plowman (News) wrote:

In article ,
Rod Speed wrote:
It'll be the output cap. Crack it open (it'll almost certainly be
welded shut. You can crack the seams carefully by squeezing them in
a vice) and replace the cap.

One of the youtube teardowns shows the use of a screwdriver handle to
whack it with can be surprisingly effective in that situation.


This one was so well welded or glued that nothing would prise it apart.
And even after cutting it open on three sides, the fourth ripped rather
than the joint giving way.

Angle grinder? Or Dremel?

I open the welded shut ones using a Stanley knife, with the blade
protruding just 2mm, which avoids damage inside, and limits the
damage to you if you slip. Ripping apart is not a problem - it
gives more surface to glue back together afterwards.

Superglue will glue most of them back together (it's actually being
used as a solvent weld in this case). At repair events, if they can't
be fixed back together securely, I regard that as terminal and dispose
of them. (If it's my own, I'll likely reuse the circuit board in another
case.)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

KVM power supply.
 

En el artículo , Andrew Gabriel
escribió:

I open the welded shut ones using a Stanley knife, with the blade
protruding just 2mm, which avoids damage inside

I've also done it by locating a Stanley knife blade (sans handle) in the
seam and tapping sharply with a hammer. The blades are brittle, though,
eye protection is a good idea. Had a couple shatter.

Most of those sealed cases can be cracked open with minimal damage in a
vice. I try the adapter in various positions within the vice, feeling
for a weak spot. Once that's found, it's easy to crack the rest of the
seam open. The advantage is that because you haven't cut it, the case
glues back together very neatly - some I've done you can't even tell
they have been opened.

At repair events, if they can't
be fixed back together securely, I regard that as terminal and dispose
of them.

Agreed. If I'm in doubt about the security of the glued joint, I add a
couple of cable ties as a belt and braces precaution. Not pretty, but
you usually can't see the adapter anyway in among all the other cables
and detritus that goes with IT kit.

--
:: je suis Charlie :: yo soy Charlie :: ik ben Charlie ::

KVM power supply.
 

In article ,
Andrew Gabriel wrote:
This one was so well welded or glued that nothing would prise it apart.
And even after cutting it open on three sides, the fourth ripped rather
than the joint giving way.

Angle grinder? Or Dremel?

I open the welded shut ones using a Stanley knife, with the blade
protruding just 2mm, which avoids damage inside, and limits the
damage to you if you slip. Ripping apart is not a problem - it
gives more surface to glue back together afterwards.


This one had a sort of stepped flange on the base about 3mm high, on to
which the cover was welded. A good weld, as it wouldn't give way.

I just used a junior hacksaw to cut through the case - better control than
a knife or angle grinder. ;-)

Superglue will glue most of them back together (it's actually being
used as a solvent weld in this case). At repair events, if they can't
be fixed back together securely, I regard that as terminal and dispose
of them. (If it's my own, I'll likely reuse the circuit board in another
case.)

Since I'm not short of space in this application, I'll put the PCB inside
a box with a flying mains lead. And better cooling. There's quite a large
heatsink on the TO 220 'transistor' so it obviously doesn't run cold.
It's not actually that old, so I'd say early cap failure even for a SMPS.

--
*Haunted French pancakes give me the crepes.*

Dave Plowman London SW
To e-mail, change noise into sound.

KVM power supply.
 

Finally got back to this and removed the faulty cap. ESR is 3.7 ohm. ;-)

It's a 1k 10v type

Closest I have in low ESR is 16v - which will obviously be higher ESR than
a 10v type.

Try it and see - or wait till I can buy the correct ones?

--
*Women like silent men; they think they're listening.

Dave Plowman London SW
To e-mail, change noise into sound.

KVM power supply.
 

En el artículo , Dave Plowman (News)
escribió:

Closest I have in low ESR is 16v - which will obviously be higher ESR than
a 10v type.

Try it and see - or wait till I can buy the correct ones?

As long as it's a 105 degC part, it'll be fine.

--
:: je suis Charlie :: yo soy Charlie :: ik ben Charlie ::

KVM power supply.
 

In article ,
Mike Tomlinson wrote:
En el artículo , Dave Plowman (News)
escribió:

Closest I have in low ESR is 16v - which will obviously be higher ESR than
a 10v type.

Try it and see - or wait till I can buy the correct ones?

As long as it's a 105 degC part, it'll be fine.

As it happens the ones I have are a different size/shape to the original,
so I've ordered up some correct spec ones from Ebay. Since I don't
actually need anything else from CPC, etc. ;-)

--
*Remember not to forget that which you do not need to know.*

Dave Plowman London SW
To e-mail, change noise into sound.