www.esabna.com
DATE: October 4, 2004 BULLETIN NO: P_04_016
TITLE/ PRODUCT NAME: PC-1250 & 1500 Output Diode Protection
RATING:
_
_ DIRECTIVE _ _ ALERT
(Action is Required) (Potential Problem)
_
X_ INFORMATION _ X _ PRODUCT IMPROVEMENT
(Action is Optional) (Enhanced Product)
_
X_ General Distribution _ _ Business Confidential
(Unrestricted) (Restricted Distribution)
PRODUCT SERIES/ MODEL:
PC-1250 and PC-1500 (60 Hz. only)
SERIAL NO:
Manufactured before serial number PX-J-441XXX (October 1, 2004)
SUMMARY:
In certain instances, normal reverse recovery of the output diodes can result in over voltage
transients beyond the capacity of the device. This event can vary substantially with the individual
characteristics of the component and is not limited to a particular batch. Certain events or
applications can aggravate this condition:
• units powered with high input voltage lines
• applications where the plasma arc frequently pops out (high voltage arcs that collapse)
• high duty cycle applications
OPERATIONAL IMPACT:
Improved reliability of output diodes
ACTION:
To insure output diode reliability, install 2 toroid filters between the main transformer and the output
diode bridge assembly during service repair. These filters absorb the energy of the transient to
better protect the diodes. We will add these toroid filters to all production PC-1250/1500 60 Hz.
units starting October 1, 2004 (before serial number PX-J-441XXX).
NOTE
Installation of these filters on older production consoles currently in
operation is not recommended due to the complexity of the installation
and risk of other failure modes occurring due to the disassembly of
the unit.