HP 8563A Service Manual

Also see for 8563A: Operating note

• WarningWarningWarningThe A6 Power Supply and A6A 1 High Voltage Assemblies contain lethalvoltages with lethal currents in all areas. Use extreme care when servicingthese assemblies. Always disconnect the power cord from the instrumentbefore servicing these assemblies. Failure to follow this precaution canrepresent a shock hazard which may result in personal injury.The voltage potential at A6A1W3 is +9 kV. Disconnect at the CRT with cautionlFailure to discharge A6A1W3 may result in severe electrical shock to personneland damage to the instrument.Always use an isolation transformer when troubleshooting either the A6 PowerSupply or the A6A 1 HV Module. When using an isolation transformer, connect ajumper between A6TP101 and A6TP301. This connects the circuit common toearth ground. Remove this jumper when the isolation transformer is not used.••Dead Power Supply1. Connect the negative lead of a DVM to A6TP301.2. Check TP308 for +5 V.3. Check TP302 for +15 V.4. Check TP303 for -15 V.5. Check TP304 for +28 V.6. Check TP305 for -12.6 V.7. Measure the voltage at TP108 to verify the output of the input rectifier. The voltageshould be between +215 V dc and +350 V dc.8. If it is not within this range, check the input rectifier, input filter, and the rear-panel linevoltage selector switch.9. Measure the voltage at TP206 to verify the output of the Kick-Start/Bias Circuitry. Thevoltage should be approximately +14 V dc.10. If there is no voltage at TP206, check TP210 for pulses 200 ms wide with an amplitude of14.7 V. If there are no pulses present, the kick-start circuitry is probably defective. If thepulses are low in amplitude (about 1 V), Q201 is probably shorted.11. If there are pulses at TP206, or there are pulses at TP210, but not at TP206, the BuckRegulator Control circuitry is probably faulty.12. Disconnect the power cord from the spectrum analyzer.13. Connect the positive output of a current-limited dc power supply to the cathode ofA6CR201 and the ground to A6TP201.14. Set the current limit to about 500 rnA and the voltage to 12 V dc.15. Connect a jumper from the power supply + 12 V output to the end of A6R202 physicallynearest A6U211.Display/Power Supply Section 12e11