ESAB PC-1250 & 1500 Output Diode Protection Troubleshooting instruction

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DATE: October 4, 2004 BULLETIN NO: P_04_016 TITLE/ PRODUCT NAME: PC-1250 & 1500 Output Diode Protection
RATING: _ (Action is Required) (Potential Problem)
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).
_ DIRECTIVE _ _ ALERT
X_ INFORMATION _ X _ PRODUCT IMPROVEMENT
X_ General Distribution _ _ Business Confidential
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.
Installation of the toroid filter is recommended during a warranty repair of the transformer or output diodes and should be completed by an experienced service technician.
Output diode failures have occurred on:
PC-1250 208-230/460v Console 0558001935 PC-1250 208-230/460v Mechanized 0558004189 PC-1500 208/230v Console 0558003517 PC-1500 208-230/460v Console 0558003570 PC-1500 208-230/460v Mechanized 0558004195
Reference information: Toroid part number: 0558005256 (2 required & provided at no charge)
The picture below shows the toroid filters installed in the leads between the main transformer and the output diode.
Toroid Filter
CONTACT:
ESAB Welding & Cutting Products Product & Service Information Group 843-664-4416 Phone 843-664-5539 FAX

Installing the Toroid Filters

Remove the power source left side panel and remove the X2 transformer leads going to the output diode bridge assembly. Install the Toroid filters (2 each) being sure they are securely tie wrapped to the X2 leads. Re-route the insulated X2 leads behind the left side and over the top of transformer to the output diode as shown in the figure below.
Output Bridge Connection
Toroid Filter
Left Side of Power Source
Left Side of Power Source
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