[Elecraft] Wall warts, et heat

[Gil WA5YKK]

  I find it both fascinating and nearly elementary when I read about 
problems and questions about wall warts. The little packages were a 
surprise to me when they first appeared, and I had to buy some extra 
"extension outlets" to plug them into, making sure that the darn 
extensions had a switch on them. It didn't take long before I lost track 
of what was plugged into what, then I noted that too many of them 
generated a bit too much heat while being "on" all day. This started 
concerning me when I noticed some hash in a receiver that was all but 
inline with a computer accessory wall wart, and led to a rethink of how 
to address the situation better.
   The whole idea really made for a big warning, when the Commodore 
outfit introduced their "cheap little computers", and unless you 
unplugged their version of a wall wart, it really heated up big time! My 
thought was "Why set up an outside power supply to just save space, and 
have a half baked, undervalued little heater to do the job?". The whole 
mess came to a head one day in a big nearby city, when a guy "rewarded 
his family with a computer", plugged it in with good faith, went out to 
eat dinner, and came home to a burned-out apartment complex! The Fire 
Marshall traced the source to that wall wart, and he got sued by his 
neighbors for the value of their lost items, then by the apartment 
management.
   He, in turn, sued the computer company, so everyone wound up in 
litigation for years, all due to a dangerous design for a power supply. 
When I had mine "sputter" on me one day, I took time to look up and 
order an aftermarket replacement, and dug into the factory version. It 
was a solid block of epoxy fill in an otherwise fair design, but due to 
the lack of cooling, it had no place to put the heat from pure aluminum 
heat sinks, and the regulators would burn out!
   My solution for all of them was to make up, if not buy, a short 
extension cord to plug into the socket strip, and have an inline switch 
to turn each one off with. I've had variations on that for a long time 
now, and one other idea worked fairly well, too, to just wait for "after 
warranty", then open the little case, note where air holes needed to be 
drilled, then ventilate them as best I could. Some didn't get ventilated 
in time, and are "hanging on a sick list" until I can get time to figure 
out a parts replacement.
   The one aspect of this whole mess is that a few of them have oddball 
voltages coming out, to power an oddball addon for a computer or radio 
accessory, so it's not a case of "simply setting up a 12 vdc strip for 
everything and grab power from a very well made, highly regulated 12 vdc 
power supply".
   I continue to clench my teeth when I see "a neat little package that 
works fine, just plug the wall wart into the wall socket and enjoy the 
toy". That's a cheap, and somewhat dangerous way to avoid adding a bit 
of bulk, a far better power supply, a switch, and some ventilation to a 
toy or rig that someone will use for who knows how long.
   The other irritant is the guy who, when he was asked "How would you 
go green", said "If everyone would simply unplug these little things, we 
could save x number of $$ in fuel for the power company". Essentially, 
he's blaming the victim for the crime.
   Maybe its time for all of us to find a way around the nonsense, look 
over our shacks, and think "safety" from the beginning. Perhaps this 
would give everyone some practice in building better power supplies?

Good luck, 73's
Gil WA5YKK