Safety Check - HP 8112A Operating, Programming And Servicing Manual

l nt;roduction to Servicing
Safety
Considerations
Warning

Safety Check

Dangerous voltages, capable of causing serious personal injury, are
present in this instrument. Use extreme caution when handling, testing
an(i adjusting.
The servicing described in the following chapters is performed with the
instrument switched on and its protective covers removed. Therefore,
servicing only be carried out by a skilled person, who is aware
must
of the hazards involved, and in ttte presence of another person who is
capable of rendering first aid and resuscitation.
Capacitors inside the instrument may still be charged after the
instrument h�s been disconnected from its external power supply
•
The HP 81 1 2A contains static-sensitive devices.
ATTENT I ON
Ensure that "static-safe " precautions are taken to
Static Sensitive
prevent electro-static discharge when the instrument
covers are removed.
The following safety checks must be carried out after any servicing is
completed:
1. Disconnect the power cord from the external voltage supply.
2. Inspect the interior of the instrument for any signs of abnormal
overheating or arcing, such as :
•
Discolored circuit board
•
Discolored components
•
Damaged insulation
If a problem exists, it
proceeding.
3. Check the case to power-cord ground-pin continuity in
accordance with IEC
the measurement to check for any intermittent discontinuity.
If a problem exists, it must be investigated and fixed before
proceeding.
4. Check the internal ground connections between circuit boards
and the instrument frame. If a problem exists, it must be
investigated and fixed before proceeding.
be investigated and fixed before
must
&
VDE. Flex the power cord during
Introduction to Servicing 1 0-1
1 0
•