"Michael Black" wrote in message
news:alpine.LNX.2.02.1606091603410.17608@darkstar. example.org...
On Thu, 9 Jun 2016, Ian Field wrote:



"Micky" wrote in message
...
On Wed, 08 Jun 2016 19:32:39 -0700, Jeff Liebermann
wrote:

On Wed, 08 Jun 2016 19:05:53 -0400, Micky
wrote:

Well this thing is pretty old. 8 years at least but I can't remember
where I bought it. Maybe it was used. D-link DI-524

Garbage. I had nothing but problems with that vintage D-Link hardware
due to line glitches. The stock 5V 2.5A JTA0302B power supply is a
known headache. They tend to last about 3-5 years before the
capacitors bulge.

Yeah, now I r emember that we talked about capacitors (on electonics
repair) the last time, and I cracked it open and looked, but I didnt'
seen any that looked swollen. Maybe I just don't know how to look.

Electrolytics don't always bulge - sometimes they get hot and expel
electrolyte past the rubber bung, when they cool, a vacuum forms and
sometimes makes the top slightly concave.

If you remove them - the dead ones usually feel lighter than they should.

The usual problem is ESR - high internal resistance, this causes losses
when filtering the output from an SMPSU. Those losses translate into heat
that you can feel - but watch out; electrolytics on the primary side of
an SMPSU can have live cans!

But it's more likely that the electrolytics on the secondary are the
problem. Those run at much higher frequencies than 60 or 50Hz from the
line, which makes them more vulnerable.

Not so with the electronic PFC front end.

The rectifier output only has a low capacitor film type - the rough DC goes
straight to the PFC circuit, that is basically a flyback boost converter,
and that's what charges the reservoir electrolytic.

Before the proliferation of PFC, I was in mainstream servicing - I had to
replace enough rectifier/reservoir electrolytics to complain about how much
they cost!

For UK mains; the PFC reservoir has to be rated 450V instead of 385V - and
handle SMPSU type ripple. So I expect they're a bit more expensive and
probably fail more often.