Briefly Disable The Shutdown Circuitry - HP 8753E Service Manual

Briefly Disable the Shutdown Circuitry

In this step, you shutdown the protective circuitry for a short time, and the
supplies are forced on (including shorted supplies) with a 100% duty cycle.
Damage to components or to circuit traces may occur if A8TP4
Caution
(SDIS) is shorted to chassis ground for more than a few seconds
1. Connect A8TP4 (SDIS) to chassis ground with a jumper wire.
Switch on the analyzer and note the signal mnemonics and test points of any
2.
off. Immediately resow the jumper wire.
3. Refer to the block diagram (Figure 5-8) at the end of this chapter and do the
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 alI assemblies that use the power supplies whose A8 LEDs
n
went out when A8TP4 (SDIS) was connected to chassis ground.
5-16 Power Supply Troubleshooting