38874R2.S - Circuit Board Installation Instructions
PDF Instructions for replacing the 38874R2.S circuit board
PDF Instructions for resetting the limits after replacing the 38874R2.S circuit board
38874R2.S Circuit Board Replacement
These instructions are written assuming that you will have ample room around Opener to perform this repair. Some rare instances will require removal of the unit from its mounting hardware and repair made on a bench or floor. Refer to your Owner’s Manual for proper assembly and carefully read and understand all warnings and cautions pertaining to your unit.
BE SURE ELECTRICAL POWER HAS BEEN DISCONNECTED FROM THE INPUT POWER LINES PRIOR TO REMOVING THE MOTOR COVER.
ANY AND ALL REPAIRS MADE TO THIS UNIT MUST BE PERFORMED WITH THE DOOR DISCONNECTED FROM THE OPENER AND IN THE CLOSED POSITION.
1. Pull the red emergency release cord on the carriage to disengage the garage door opener to close the garage door if necessary. (If you cannot lower the garage door using the garage door opener, use extreme caution manually closing the garage door. Before pulling the emergency release cord, make sure people and objects are clear of the garage door opening.)
2. Unplug the garage door opener power cord from the outlet.
3. Open the light lens cover by pressing the middle tab inward and remove the light bulbs. FIG. 1.
4. Remove Safe-T-Beam and wall console wires from the terminal block located on side of the powerhead FIG. 1. Use a screwdriver (small one works best) to press in on the orange tabs while gently pulling out the wires from the terminal block. Marking the wires now can help when replacing them later in the instructions.
5. Unplug any additional optional accessories installed such as a battery backup and/or network adapter.
6. Remove the two 5/16” screws securing the powerhead cover to chassis. FIG. 2.
7. Allow the motor cover to slowly swing down to gain access to the control board and wire harnesses.
8. Unplug all the following wiring harnesses from the control board. FIG. 4.
• Light harness
• Motor harness
• Opto harness (see step 12-13)
• AC IN harness
• Motion Detector harness (if equipped)
• Green ground wire to chassis (if equipped).
REMOVE AND DISCARD.
9. The powerhead cover can now be removed from opener chassis for repair. If your model garage door opener has a motion detector- Special care should be taken to prevent damage to the motion detector bulb located on the bottom of the motor cover.
10. Remove the three circuit board mounting screws and the old board. FIG 3.
11. Feed the new antenna wire through the hole in the cover. Mount the new replacement control board 38874R2.S to the cover and now secure with the three screws removed in step 10.
--- SEE BELOW FOR MOTOR TYPES ---
12. If your motor compares to MOTOR TYPE 1. Remove existing harness from the motor and plug pre-installed OPTO SENSOR harness from new control board directly into the motor.
13. If your motor compares to MOTOR TYPE 2. Remove pre-installed OPTO SENSOR harness from the control board and plug existing OPTO harness from the motor into DUAL ENCODER OPTO SENSOR plug on replacement control board. (Or use new harness packed with control board).
14. Hang powerhead cover to chassis to connect all other harnesses removed in step 8.
15. Swing powerhead cover up onto chassis and secure using screws removed in step 6.
16. Install wall control and Safe-T-Beam wires. Install battery backup and/or network harnesses if applicable.
17. Install light bulbs and close lens cover.
18. Reapply power to opener.
19. Limit controls, transmitters and full function test will be required. Refer to the owner’s manual and/or assembly poster for detailed information