On 05/06/10 10:55, Tony Duell wrote:
Argh!. I can remember when Maplin sold some
reasonable-quality tools.
Like 'Elora' spanners (They did a few very small sizes that were very
difficult to find). And Weller soldering irons (I bought at least one b=
it
for my TCP from them). Not any more :-(.
They used to stock the Antex 660TC soldering station. I got one as=20
"discontinued stock" a while ago for a good bit less than the RRP. That=20
When i was in Bristol, every year the Maplin shop sold off the
kits/PCBs/components that were being disocontinued and no longer listed
in the catalouge. I got a lot of bags of interesting mixed ICs that way,
a number of interesting kits, and other bits. It's why I have 3 or 4 bare
PCBs for the Maplin Modem in the spares box, for example...
And they
don't sell tin/lead solder any more.
But Farnell still do :)
Sure (and I think RS do too). It's not difficult to get, I was simply
pointing out that Maplin don't sell it. Since they generally sell to the
hobbyist market (who AFAIK are allowed to use whatever solder they want),
I find this somewhat strange...
The Multicore stuff is fiercely expensive, but the
stuff they stock as=20
"Multicomp" (i.e. "whatever was cheapest at the time") is pretty
decent.=20
At one point the Multicomp stuff was badge-engineered Multicore "562"=20
60/40 SnPb or something very close to it.
I've had problems with 'Multicomp' components from Farnell. Not the
solder (I've never tried it), but I've had some very poor connectors. I
eneded up replacing them with genuine 3M ones at 6 times the price (if
I'd spotted Farnell also listed those I would never have bought the
Multicomp ones...). My sanity in only having to trace genuine faults in
my HP Multiprogrammer system ius worth something...
> * PC power supply. Blew up and took an
expensive motherboard and CPU=3D=
20
> with it. Even put a PSU tester on it, which
showed the +12 rail at=3D2=
0
> almost 20V! -- "We'll replace the
power supply but you'll have to RMA=3D=
20
That's an odd fault... With many SMPSUs the 'extra' outputs will be low
if the main output is not sufficiently loaded, but having such ouptus g=
o
(very) high is uncommon. I wonder what the fault
was.
I suspect a short in the transformer. Whatever it was, it made a loud=20
bang and dumped a lot of Magic Smoke...
A shorted turn in an SMPSU chopepr transformer will always blow the
chopper transistor (and other bits in the PSU), it doesn't normally make
the oputputs go high,
Incidentally,
my common comment 'Check the PSU on dummy load' applies t=
o
brand new PSUs too :-).
"Dummy load / PSU tester" is right on the top of my "stuff to build"
list=
:)
I just have to figure out how to do the "constant power" regulation. I=20
You don't need to go that far. Filamanet lamps (!) of suitable rating are
enough.
want to go with opamps for the regulation (faster
response time to V/I=20
transients) and a D/A to set the current/voltage/power 'setpoint'.
Why do yuo want to overcomplicate everything. Sounds like some of the
magazine projects that have to use a microcontroller when there are much
simpler ways of doing it.
-tony