Agilent Technologies E4351B, E4350B service manual 5. No Display Troubleshooting

No Display Troubleshooting

"No Display"

Start

Turn on the supply and try to program it from the front panel. While measuring the voltage at the output terminals, program the voltage and current to full scale. Toggle the ON/OFF key while observing the external voltmeter.

No display but output	No
OK
?

Yes

Turn off supply, remove front panel assembly to access circuits on the A3 front panel board. Turn on the supply.

Check 5V bias at R1-6, display voltages: 1.1V at R1-14, 2.2V at R1-2 and 3.3V at R1-16 (meter common at R1-3). See Fig. 6-4.

Check the A2 GPIB board, bias circuits, PCLR (test points 1 - 4 Table 6-3) and cable W9

		Check A3C1,
Display and bias	No
		A3R1 and A3RT1.
voltages OK
?

Yes
Check 10MHz Clock signal at
A3J2-9. See Fig. 6-9.
		Yes
		Check A3Y1,
Display and bias	No	A3C3, A3C4 and
voltages OK		A3U3.
?

Program voltage and current fron the front panel. Measure the voltage at the output terminals. In case the output is disabled press the output ON/OFF key while observing the output with an external voltmeter.

A3U3, A3U4 or A3U8
defective. Perform
	No		Output Voltage present
front panel SA. See
		?
Table 3-4.
				Yes
		LCD or cable W19 defective.

Figure 3-5. No Display Troubleshooting

14 Service Addendum