Agilent Technologies E4351B OV at Turn-On Troubleshooting, 7. OV at Turn-on Troubleshooting

OV at Turn-On Troubleshooting

"OV at Turn-On"

Start

Check that the supply is not programmed to OV at turn-on. Ensure that the voltage setting is not greater than the OV setting. Program 0V and Max. OV, then save the settings in Register 0 (press shift, save, 0 and Enter key). Turn the supply off then back on.

Connect a DC coupled scope across the output terminals. Turn the supply on and check that the output does not momentarily go higher than the voltage setting.

Momentarily goes high		Yes
?
	Yes

Caution: During these tests, the output may be at hazardous levels.

Turn off the supply and remove the top cover. Disable the OV circuit by lifting A1R447. Turn on the supply and check the output voltage.

					Go to "Output Held High"
Output high			Yes
					Troubleshooting
?
	Yes
				Check A1R447,
OV still ocurrs		Yes
				R446, C417
?

Check voltages at A1U405-7 (TP44), U603-5 (TP17,
U405-5 (TP42) and U405-3 (TP41) to Common		Check A1U405.	Yes	A1U405-7 approx 5V
(TP9). See Table 6-3.
				?
		No		No
A1U405-7 approx 5V	Yes	Check A1U411.
?		Check A1R644,	Yes	A1U405-7 approx 5V
		C417.
				?
				No
				Replace A5 DSP board

Figure 3-7. OV at Turn-on Troubleshooting

16 Service Addendum