ASCO G7ATB / G962 — Solenoid Assembly Replacement
Repair & overhaul
For the ASCO G7ATB / G962, from the ASCO service manual.
Before you start
- To prevent the possibility of personal injury, be sure to pin the weight to the frame so that the mechanism cannot move while removing the solenoid assembly.
- The solenoid assembly weighs about 35 lbs.
- To prevent coil burnout in the new solenoid assembly be sure to remove the adjusting pin so that the mechanism is free to operate again.
- To prevent the possibility of personal injury, fully insert the maintenance handle into the hub and grasp and hold it firmly when you remove the adjusting pin. Gently allow the contacts to close.
- To prevent possible damage to the transfer switch and interruption to the load, check main contact adjustments after replacing the solenoid assembly.
Procedure
- Bypass, isolate, and pull out the transfer switch and verify that no electrical power is present.
- Manually operate the switch to the Emergency position using the maintenance handle so that the core link is down (Normal contacts open).
- Disconnect the solenoid assembly: squeeze the plug latches and separate the in-line wire harness plug to the coils.
- Remove both shaft indicator plates (left side) using a 3/8 in socket wrench to remove two screws.
- Pin the weight to prevent mechanism movement: insert the adjusting pin through the weight frame into hole 6 (bottom left hole adjacent to the center operator shaft, 7 o'clock position).
- Remove the solenoid assembly: first remove the two left rear hex-head bolts with a 1/2 in socket wrench and 6 in minimum extension, then remove the six other bolts (2 left, 4 right).
- Carefully pull out the solenoid assembly, unhooking the core link from the post on the weight, and swing out the left side first; it weighs about 35 lbs.
- Install the replacement solenoid assembly with the core link facing right and the coil wire harness plug on top; put the right side in first and hook the link onto the post on the weight.
- Reinstall two longer screws in the left rear, then six hex-head bolts (4 right above and below the flanges, 2 far left side front); tighten all eight bolts to 11 ft lbs.
- Reinstall the two shaft indicator plates (left side) using a 3/8 in socket wrench to install two screws.
- Connect the new solenoid assembly: connect the keyed in-line wire harness plug and the plug from the coils, and be sure both latches click.
- Unpin the weight: fully insert the maintenance handle, grasp and hold it firmly, remove the adjusting pin from hole 6, and gently allow the contacts to close.
- Manually operate the transfer switch several times; it should operate smoothly without binding. If not, check that the solenoid is installed correctly.
- Check main contact adjustments (pages 6-8) before returning the transfer switch to service.
- Return the transfer switch to service per Section 3 of the Operator's Manual.
Tools required
- maintenance handle Amazon
- adjusting pin Amazon
- 3/8 in socket wrench Amazon
- 1/2 in socket wrench with 6 in minimum extension Amazon
- 1/2 in socket and/or open-end wrench Amazon
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 11 ft lbs
- solenoid assembly weighs about 35 lbs
Source: ASCO service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.