Troubleshooting Ac-Turn-On Circuits; Troubleshooting Dc-To-Dc Converter - Agilent Technologies 6033A Service Manual

Troubleshooting AC-Turn-On Circuits

Relay AlK1 closes at 1.0 seconds and DROPOUT goes high at 1.1 seconds after 20V (5V UNREG) reaches about 11Vdc.
DROPOUT high enables the PWM if OVERVOLTAGE , INHIBIT , and OVERTEMP are also high.
Circuits Included. AC-Surge-&-Dropout Detector, Bias Voltage Detector, U11A, 1-Second Delay and Relay Driver--all on
A2 control board.
Setup. The Main Troubleshooting Setup, Page 48. Apply the ac mains voltage to the bias transformer, and set the external
supply to 0Vdc.
Inputs:
NODE (+) *
A2J3-1
A2J3-22
A2U20-8, 10
A2U22-13
Outputs:
NODE
A2U20-5
A2U20-2
A2Q6-1
A2Q6-9
A2U20-6
A2U20-1, 14
A2U11-3
A2U18-10
A2U18-13
A2U18-12
A2U18-15
A2U17-8
A2U17-11
( DROPOUT )
A2Q5 (col.)
(RELAY ENABLE)

Troubleshooting DC-To-DC Converter

Parallel NOR gates A4U2A, A4U2B and A4U1A act as drivers and switch on PFETs A4Q3 and A4Q4 through pulse
transformer A4T1. NOR gate A4U1B turns off the PFETs through pulse transformer A4T2 and transistors A4Q1 and
A4Q2.
Circuits Included. On-Pulse Driver, Off-Pulse Driver, PFET Switches and Drivers on A4 power mesh board.
Setup. The Main Troubleshooting Setup, Page 48. Apply the ac mains voltage to the bias transformer, set the external
supply to 40Vdc, and switch on the LINE switch. Set the unit's output voltage to 20Vdc and current to above 1Adc. Verify
that the OVERRANGE LED lights. See Figure 3-7 for waveforms.
SETUP MEASUREMENT
wait 2s 5.0Vdc
20Vdc A1CR6, A1CR7
f.w. rect, 1-2V pk
TTL sq wave, 20KHz
SETUP MEASUREMENT
cycle power transition 0 to 13.5Vdc
cycle power transition 0 to 1.4Vdc
cycle power transition 0 to 5.0 to 0.3Vdc
cycle power transition 0 to 0.3 to 5.0Vdc
wait 2s < 0.25Vdc
wait 2s Hi (5Vdc)
cycle power transition Lo to Hi to Lo
cycle power burst 1.25khz sq. wave, 1.1s
cycle power five 100ms pulses then Hi
cycle power two 200ms pulses then Hi
cycle power transition Lo to Hi at 800ms
cycle power transition Lo to Hi at 1.0s
cycle power transition Lo to Hi at 1.1s
cycle power transition 5.0 to 0.3Vdc at 1.0s
SOURCE
A2Q3 (emit.)
A1CR8,A1CR9
A2U22-6
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