-20 to -50 kV HVPS repair

[Victor Gonzalez]

I have an X-ray fluorescence spectrometer and it's HVPS broke some time ago and I spent many hours fixing it, here is few things that I learned.

This HVPS was made by Philips (I believe it's their own design, modern spectrometers use Spellman's HVPS), and it's aiming at high stability (Stability 0.0005 %/% mains variation), it's designed to operate 24H at full power (-50 kV, 4 mA, 200W), the x-ray tube is water cooled.

This power supply has 5 main stages to generate HV:
230 V AC Step-up converter to 400V DC
Buck converter for controlling the HV (+-100 kHz)
H-Bridge to drive the transformer (+- 50 kHz)
Flyback type transformer (1:5 ratio)
Cascade multiplier that has voltage and current feedback

board sections

Board under test

Step Up circuit

buck, H-bridge circuit

HVPS - XRay tube working

Hope this helps anyone who is trying to build or to repair a HVPS

[Victor Gonzalez]

Re uploading the pictures

Brown - Transformer
Red- Step-up and PFC
Orange - Buck converter
Green - H-Bridge
Yellow - cascade multiplier (Cockcroft-Walton multiplier)