Finish Thompson BE-15/15C - Manual (Page 14)

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Possible Cause 4 & 5: On/off Switch is defective and/or
Level Control Board’s relay not closing.
There is a small relay mounted to the Level Control Board. The terminals for this relay’s output are located
on the lower right corner of the board and labeled “NO”, “COM”, and “NC”. Whenever the board’s red LED
is lit, the contacts between “NC” and “COM” should close and energize the coil on the On/off Switch. This
can be checked by measuring for voltage at the On/off Switch.
Electrical shock hazard present.
Be careful when performing voltage measurements on live electrical circuits.
If TAS2 and TAS4 have checked OK, measure for voltage at the On/off Switch. For units E91 through E92,
there should be 120V between wires #10 and #24. For units F92 or newer, there should be 240V between
wires #26 and 1L2.
 If there is proper voltage at the on/off switch, and all other tests have passed, the On/off Switch is
defective and must be replaced.
 If there is not proper voltage at the On/off Switch, disconnect power to the BE unit and temporarily
bypass the Level Control Board. The board is bypassed by connecting a jumper wire between the
wires connected to the “NO” and “COM” terminals. Restore electrical power. If the unit turns on,
the Level Control Board must be replaced.
 If the BE unit still will not turn on, then the On/off Switch and Level Control Board are defective and
must both be replaced.
If the On/off Switch or Level Control Board are defective, check all electrical connections for shorts to
ground. See the “Important” note in the beginning of this “Service Procedure” section.
WARNING: