Phasetronics
Page 21
8.2 - Replacing Printed Circuit Boards
The printed circuit boards are not intended to be field repaired. If a board is found to be faulty the entire
board should be replaced. Note: 10-50A units require soldering to disconnect and reconnect the SCR
Gate/Cathode leads.
Persons not adequately trained to solder should not be allowed to change
the PCB.
The 85 thru 1000A units use a plug connection method for the SCR leads and are easily changed.
WARNING
Remove all power sources from the unit! Disconnect load and line leads. Observe
all lock out / tag out practices.
Important!
Use ESD Precautions any time you replace circuit boards.
1. Remove all power sources and lock out.
2. Units 85-1000A: Unplug the orange connector at the J1 location.
3. Units 10-50A: Using diagonal cutters cut the SCR gate/Cathode leads about 1/4 inch under the
board leaving a small bit of insulation. This will provide fresh wire for the install and leave color
coded stubs in the defective board for lead identification purposes.
4. Tag all control wires and remove from their terminal blocks
5. Document all Potentiometer settings and jumper configurations.
6. Using a Philips Screwdriver, remove all the PCB mounting screws.
7. Remove the defective PCB assembly.
8. Units 10-50A: Strip 1/4 inch from each SCR lead to prepare for soldering.
9. Units 10-50A: Insert each SCR lead into the correct hole by color code and solder.
10. Mount the new PCB assembly.
11. Re-install the mounting screws.
12. Re-install all control wires disconnected earlier.
13. Configure all Potentiometer & Jumpers to the same position/location as the old PCB.
14. Units 85-1000A: Plug in the Orange connector disconnected earlier.
15. Inspect all work and clean area of tools before applying power to test.
8.3 Replacing SCR Devices
The SCRs utilized in the
EP1 series
are not field serviceable. If by using the procedures in section 8.1
you have determined there is a failed SCR, please consult the Phasetronics Return Material Department
for a return Material Authorization Request Form or a factory authorized repair center for assistance.
8.4 Calibration Procedures
All EP1 units are factory calibrated for 0 to 100% proportional control. The following procedures can be
used to restore the factory alignment if you encounter a situation where all the potentiometers on the EP1
have been misadjusted due to field calibration attempts and normal control of the unit has been lost.
