[time-nuts] Anybody want a Thunderbolt power supply?
csteinmetz at yandex.com
Thu Sep 1 01:07:53 EDT 2016
> Wow, given all the responses about the cleanliness of the power into a Thunderbolt, I would be even more interested in a power supply that did *not* leave the "last mile" up to me. I would be more interested in a "pretty clean" power supply that I could just plug in and go. Any thoughts of me actually wiring the last bit of it make me break out in a cold sweat and come face to face with my (established, and sadly slow-to-expand) limitations.
> Maybe I'm the only one that would be interested in such a solution? I hope not, but I can see that there is a lot to consider about such a thing.
For those who need an absolutely-no-soldering solution, there are any
number of good, triple-output linear lab/bench supplies. My first
choice among these would be the Power Designs "TP" series -- TP325,
TP340, TP343 (and their "A" and "B" successors). The HP 6236A (and B)
are also good candidates, although the +/-0-20v supplies are only good
for 500mA -- so the +12v supply to the Tbolt sits in 500mA current limit
for a short time while the Tbolt oven warms up from a cold start (not a
problem, just an irregularity).
Tested and guaranteed samples of all of these can be bought for $25-100
if you are patient (pay no attention to the loonies who list them for
There are two potential disadvantages. The first is size (particularly
WRT the Power Designs units -- the HPs are much smaller). The second is
their adjustability. You would not want to brush against one of the
voltage-setting knobs accidentally and send your Tbolt to GPS heaven.
The cure for this is a small dab of RTV on each knob. Set the supplies
to the desired voltages, then apply a dab of RTV from the skirt of each
knob to the front panel of the supply. Check the voltages while the RTV
is still workable, and adjust if necessary. Let the RTV set, and it
would take some effort to change the voltages.
If your Tbolt came with a switching PS that you are replacing, you
probably already have a power cable that terminates in the proper Molex
connector to feed the Tbolt. But what if you don't? You will need to
build a power cable using the correct Molex connector shell (Molex p/n
50-57-9406) and contacts (Molex p/n 16-02-0103). The contacts are made
to be crimped to the wires from the power supply. The Molex crimp tool
(Molex p/n 63811-8700) is breathtakingly expensive (about $350). Others
are less, including (I am told) a pretty cheap one from Radio Shack.
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