[time-nuts] Thunderbolt and UPS, Was any negatives ?

[Mark Sims]

A slick way of adding a Tbolt monitor and UPS is to use an old laptop that has a CD drive that runs off of a 12V supply.  Most CD drives draw a similar amount of power as the Tbolt.  Remove the CD drive and power the Tbolt off of the internal laptop power lines (you will also need a +5V and -12V signal which are readily available in the laptop).  Voila,  battery backed Tbolt with a nice full time interface/status screen.    

A suitable laptop can be had for around $20.  You will probably need to spring another $40 or so for a fresh battery.  If your chosen laptop is old and kludgy enough you may even be able to squeeze the Tbolt inside the laptop case where the old drive mounted.  

The downside of this is the laptop supply may be electrically noisy and inject some noise components into the Tbolt output signal,  but then Tom's testing shows every supply does this to varying degrees.
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