[time-nuts] HP Equipment Running Hot as Heck...

Richard (Rick) Karlquist richard at karlquist.com
Thu Jan 28 04:34:30 UTC 2016

Vintage HP equipment often had HP made power transformers,
which ran all the time whether the equipment was on or off.
The core loss while idling could be fairly high.  The
core was usually just below saturation, so that if the
power switch was on 100V, it would really get hot.

There was some logic analyzer model that HP engineers
referred to as the "logic furnace" because it ran
so hot.

Rick Karlquist N6RK

On 1/27/2016 4:22 PM, Burt I. Weiner wrote:
> Don,
> Something to be careful of... Be sure the mains voltage switch is set
> properly. I had a HP-3336A that ran hot like that. Like you, I put
> bigger and bigger heat sinks on the regulator, but all that seemed to do
> was make the bigger heat sinks as "hot as heck" also. What I discovered
> was that the mains voltage selector was set to 100 volts. I reset it to
> 120, (or was it 117) and it ran much cooler.
> Burt, K6OQK
> From: "Don Latham" <djl at montana.com>
> Someone has already probably said, watch out for switching regulators.
> BTW,
> almost all the Hp instruments I have from the 80's era run hot as heck.
> I have
> put on fans and piggybacked more fins (and more fins, and more fins...).  A
> Military version of the 5328A counter I have has what sounds like a leaf
> blower in it, with a proportional controller added.
> If you do some work with switchers, I'm sure the list would be very
> interested!
> Don
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California  U.S.A.
> biwa at att.net
> www.biwa.cc
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