[time-nuts] Replacement Backup Battery for 5065A?

Ed Palmer ed_palmer at sasktel.net
Mon Feb 26 13:51:39 EST 2018

On 2018-02-26 11:00 AM, Corby wrote:
> Also I usually remove a battery A2 and install two shottky diodes on the
> underside of A2s chassis jack.
> Non-battery units have an A2 that just has these two diodes on it.

On mine, I didn't bother with schottky diodes, I just used half of a 
bridge rectifier that I bolted to the chassis.  Removing the battery 
charger version of the A2 board also removed a significant amount of 
heat from the unit.  That board runs quite warm!

Another interesting point about removing the A2 board is that in 
addition to freeing up a card slot, it frees up the transformer winding 
that was used for the battery charger.  Maybe use that to build a 5V 
supply for some new add-on.  The A2 board was rated for ~25V @150 ma or 
~3.75W.  At 5V, that's 0.75A.  You'd probably have to use a switching 
supply.  Extra care would be required to make sure that the supply's 
switching noise didn't degrade the unit's performance.


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