Friday, September 2, 2016

SSPA Power Supply - Voltage increase Mod

As mentioned in my last post here I will be wanting to increase the voltage output of each dps-1200fb power supply in this new system from 12.5 to 13.5.  The result is that the series output of four of these supplies will be 54 vdc instead of 50.   the dps-1200fb has a protection that will shut the supply down at 12.8+ vdc unless this mod is completed.

I'm doing this to overcome the diode drop of the protection diodes I'm installing this weekend.  When at full load I want this to result in 50 vdc output.

There is an expected sum total diode drop of almost 4 vdc. (if my calculations are correct).  If not I'll just do this mod and tune the supplies to the output required to accomplish 50 vdc at max load.

I'm replacing the oem pot shown in the pictures below with a Panasonic 2K Ohm pot p/n: P3Y202CT-ND available here.


WARNING: 

If you decide to attempt to do this...be sure to use a fair amount of flux.  Make sure that you have the two pads that are on the same side heated evenly before you attempt to lift the pot or you will probably tear the solder pad and it's trace off of the circuit board!

You have been warned!  Take your time, and make sure you follow this advice.


Partially removed

removed

Installed - New

Installed

(Left is the new one, right is the old one)