Step Action Response Probable Cause | Agilent Technologies E3614A

		Table A-3. Overall Troubleshooting (Cont’d)

SYMPTOM		CHECKS AND PROBABLE CAUSES

Poor Load Regulation	a.	Refer to "Measurements Techniques" paragraph.
(Constant Voltage)	b.	Check +10 V reference voltage.
	c.	Ensure that the supply is not going into current limit.

Poor Load Regulation	a.	Check +10 V reference voltage.
(Constant Current)	b.	CR1, CR19, CR20, C2, C31 leaky.
	c. Ensure that the supply is not crossing over to constant voltage operation.

Oscillates (Constant Voltage/	a.	Check C29 and C36 in constant voltage circuit.
Constant Current)	b.	Check C31 and C33 in constant current circuit.

Poor Stability	a.	Check +10 V reference voltage.
(Constant Voltage)	b.	CR27, CR28, CR23, and CR26 leaky.
	c.	U9 defective.
	d. Noisy programming resistor R83.

Poor Stability	a.	Check +10 V reference voltage.
(Constant Current)	b.	CR24, CR25, CR29, and CR30 leaky.
	c. U9 and U10 defective.
	d. Noisy programming resistor R85.

Excessive heat	a.	Check preregulator control circuit. Refer to Table A-6.
	b. CR10, CR12, CR15, and CR18 short

OVP Shutdown	a.	Check that the front panel OVP Adjust screw control is rotated fully clockwise.
	b. Check the overvoltage protection circuit.
		Refer to "Overvoltage Protection Circuit Troubles" paragraph or Table A-7.

Table A-4. High Output Voltage Troubleshooting

STEP	ACTION		RESPONSE		PROBABLE CAUSE

1	Check turn off of Q1 and	a. Output voltage remains high.		a. Q1 or Q4 shorted.
	Q4 by shorting Q9 emitter	b.	Output voltage decreases.	b.	Remove short and proceed to step 2.
	to collector.

2	Check turn on of Q9 by	a. Output voltage remains high.		a.	Q9 open.
	shorting point 1 to -12 V.	b.	Output voltage decreases.	b. Remove short and proceed to step 3.

3	Check voltage from pin 5	a. Input voltage is positive.		a.	U9B is defective.
	to pin 6 of U9.	b.	Input voltage is negative.	b. Turn down the voltage control fully
					counter clockwise. Check the voltage
					of U9 pin 1 is 0.

Table A-5. Low Output Voltage Troubleshooting

STEP	ACTION		RESPONSE		PROBABLE CAUSE

1	Check turn on of Q1 and	a. Output voltage remains low.		a. Q1 or Q4 open.
	Q4 by disconnecting emitter	b.	Output voltage increases.	b.	Reconnect emitter lead and proceed to step 2.
	of Q9.

2	Check turn off of Q9 by	a. Output voltage remains low.		a.	Q9 shorted.
	shorting point 1 to +15 V.	b.	Output voltage increases.	b. Remove short and proceed to step 3.

3	Eliminate constant current	a. Output voltage is increases.		a. Proceed to step 4.
	comparator as a source of	b.	Output voltage remains low.	b.	Reconnect lead and proceed to step 5.
	trouble by disconnecting
	anode of CR22.

A-10

STEP