Brother BAS-311E service manual Chapter

Chapter 7

Error status Probable causes

4.Power PCB defective.

Check/repair/adjust

•Measure the resistance between a terminal in the center of the power PCB and pin 2 in connector P5

(DC300).

The resistance should be ∞Ω.

•Remove connector P12 (POWER) on the control circuit board, turn on the power, and measure the voltage across pins 4 and 6, pins 5 and 6, pins 5 and 7 on the cord.

The voltage in each case should be +55V. Measure the voltage across pins 2 and 3. The voltage should be +20V to 24V.

After measurement, turn off the power, wait at least 5 minutes, and insert P12.

Parts to be replaced

Power PCB

Work clamp for pneumatic specification (BAS-311E and 325E)

#4
The work	• Pull out connector P4 (AIR) on the control circuit
clamp does 5. The air valve is defective.
not move	board and measure the resistance between the
up and	following pins in the connector on the cord:
down	Pins 1 and 10	(air valve for right work clamp)
when the	Pins 2 and 10	(air valve for left work clamp)
foot switch	Pins 3 and 10	(air valve for presser foot; only
is stepped	for optional specification)
on.	The resistance in each case should be 300 - 400 Ω.

6. The control circuit board (#3) is	• Pull out connector P4 (AIR) and measure the
defective.	voltage across the following pins in the connector
	on the PCB:
	Pins 1 and 10	(air valve for right work clamp)
	Pins 2 and 10	(air valve for left work clamp)
	Pins 3 and 10	(air valve for presser foot; only
	for optional specification)

The voltage in each case should be +20V to 24V. After measurement, turn off the power, wait at least 5 minutes, and insert P4.

Air valve

Valve harness assy.

Control circuit board.

BAS-311E.311EL.326E.326EL 107