[time-nuts] Thunderbolt Power

Chris Albertson albertson.chris at gmail.com
Fri Jul 26 15:47:33 EDT 2013

On Fri, Jul 26, 2013 at 11:17 AM, steve gunsel <steve at sgteq.com> wrote:

> Hi,
> I recently purchased a surplus Trimble Thunderbolt and would like to get
> it going. The 24 volt units have a fairly wide range of acceptable
> voltages. The only power supply specs I can find for mine specify +5, -12
> and +12. No min-max is specified. I have a power supply that has +5, +15
> and -15 volts available that I'd like to use but not unless within
> acceptable limits. Does anyone know what the power supply specs are?

It is very easy to take 15V to 12V with a three terminal regulator.  Use a
good heatsink on the +12V reg.   You can drop some of the voltage ahead of
the regular with power resister.

That said, this thing is going to run 24x7 for hopefully years and you
don't want to pay for all that wasted power.  Get a 12V power supply

On the other hand you can put that heat to good use.   I designed a fan
controller with a smal temperature sensor, an opamp and a power transistor.
 It keeps the temperature inside the box reasonably constant.  I have the
power supply (salvaged from a Cisco router) the regulator board and the
Thunderbolt all in an old Disk Array enclosure.

So there are several correct answer, depends on how much work you want to
do.  Simplest is to replace the power supply.

Chris Albertson
Redondo Beach, California

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