Condor GPC41-5G 5V to 180V/40W Conversion
GPC41-5 datasheet
Schematic (Original) / BOM
Schematic (Modified)
UC3844 datasheet
Transformer redesign
Core / Material

     The GPC41 series are universal input (100-240VAC, 50/60Hz) switching power supplies with 40W output capability.  By modifying the transformer and adjusting the output regulation circuits, this unit can easily deliver 230mA at 180V at 70% efficiency for those giant nixie projects.  The new 5V output can supply 200mA when the main 180V output is unloaded and 500mA (Power dissipation limited) when the main output is loaded at or above 60mA.

International Power Systems PU40-10SL transformer
100-240VAC input, 5V/8A

Center leg gap

Bias=9T single

Secondary=4T 8F

As I pull apart transformers, I put the pieces in order above my desk from right to left.
Core removal fixture

Two 15 ohm power resistors in parallel with about 40W of input power.  Heating should be done slowly so that the temperature differential from the core center to the leg end is no more than about 5C to prevent thermal cracking;  covering with fiberglass will insulate the core so that the convection cooling won't force you to drive the heat up too high.  When the core is uniformly about 125C, the cores may be carefully be pulled from most bobbin/varnish combinations with extra care to prevent squeezing the legs inward which will break them.

  Any questions or comments?
This page last updated on August 05, 2010