Hypertherm PMX1000 Reference manual

PMX1000 & PMX1250
RCD Resistor Replacement
Field Service Bulletin
804950 – Revision 2 – July, 2017
Hypertherm Inc.
Etna Road, P.O. Box 5010
Hanover, NH 03755 USA
603-643-3441 Tel [phone] Fax
www.hypertherm.com

RCD RESISTOR REPLACEMENT
Field Service Bulletin 1
Introduction
Purpose
Describes necessary steps to replace the RCD resistors (R119 and R120) on the power board of the PMX1000 and
PMX1250.
Note: This upgrade only applies to power supplies with serial numbers prior to:
PMX1000 – 1000-013717
PMX1250 – 1250-007888
Tools Needed
Phillips head screwdriver
Wire cutters
Kit Contents
Item Part Number Description Qty
1 109529 24K 13W resistor 2
WARNING
ELECTRIC SHOCK CAN KILL
Disconnect electrical power before performing any maintenance.
All work requiring removal of the power supply cover must be performed by a
qualified technician.
See Section 1 of the Operator Manual for more safety precautions.

RCD RESISTOR REPLACEMENT
Field Service Bulletin 2
Replace damaged resistors
1. Disconnect power and remove cover from power supply.
2. Discharge capacitors C94 and C98. See photo below.
3. Use wire cutters to remove resistors R119 and R120.
Note: cut leads next to the surface of the power board.
WARNING
ELECTRIC SHOCK CAN KILL
Use a multi-meter in VDC mode to discharge the capacitors to
less than 10VDC before removing the mounting screws.
Cut 4 places as shown
C98
C94
C98
C94
4. Remove screws from capacitors C94 and C98 as show.
R119
R120

Resistor (2)
Field Service Bulletin 3
Correct Installation
5. Install new resistors on capacitors C94 and C98 as shown. Tighten screws to 20 inch pounds (24 kg cm).
Note: Align bleeder hole on capacitor with view hole on power board.
6. Install power supply cover.
Bleeder hole
View hole (2)
Torque screws (4) to
20 inch pounds (24 kg cm)
CAUTION: Cross-threading the screws may cause
the capacitors to fail.
Note: assemble in the following order.
PCB, resistor, large terminal, small terminal, screw
C94
C98
© Copyright 2017 Hypertherm Inc.
All Rights Reserved
Hypertherm and Powermax are trademarks of Hypertherm Inc.
and may be registered in the United States and/or other countries.
RCD RESISTOR REPLACEMENT