Briefly Disable The Shutdown Circuitry - Agilent Technologies HP 8719D Service Manual

11. Reinstall each assembly one at a time. Switch on the analyzer after each
assembly is installed. The assembly that causes the green LEDs to go off or
flash could be faulty.
Note
It is possible, however, that this condition is caused by the
this, reinstall the assemblies in a different order to change the
loading. If the same assembly appears to be faulty, replace that
assembly. If a different assembly appears faulty, A8 is most
likely faulty (unless both of the other assemblies are faulty).

Briefly Disable the Shutdown Circuitry

In this step, you shutdown and disable the protective circuitry for a short time,
forcing on the supplies (including shorted supplies) with a 100% duty cycle.
Damage to components or to circuit traces may occur if A8TP4
while supplies are shorted.
1. Connect ASTP4 (SDIS) to chassis ground with a jumper wire.
2.
Switch on the analyzer and note the test points of any LEDs that are off.
3. Refer to the block diagram (F'igure 5-7) at the end of this chapter and do the
following:
Note the mnemonics of any additional signals that may connect to any A8
n
test point that showed a fault in the previous step.
Cross reference all assemblies that use the power supplies whose A8 LEDs
n
went out when A8TP4 (SDIS) was connected to chassis ground.