A7 Midplane Board Assembly; Instrument Power Supply Leds And Test Points; Additional Power Supply Regulation; Instrument Secure Storage - Agilent Technologies N9039A Service Manual

Troubleshooting

A7 Midplane Board Assembly

A7 Midplane Board Assembly

The A7 Midplane board assembly is serviced as an assembly only; no component
level repair is supported. For details on the functionality of this assembly see
Chapter 3, "Assembly Descriptions".
In addition to providing electrical connection between some of the different
assemblies within the instrument there are a few other functions that the A7
Midplane board assembly provides, that if not functioning properly, could cause a
failure in the instrument. They are:

• Instrument Power Supply LEDs and Test Points

• Additional Power Supply Regulation

• Instrument Secure Storage

• Power supply dithering

Instrument Power Supply LEDs and Test Points

While the A6 Power Supply assembly has no user accessible LEDs or test points
the A7 Midplane board assembly does provide these for all of the different
instrument power supplies as well as many of the power supply status lines. A
complete list of these can be found in the Table 2-3 and the location of each can be
seen in Figure 2-15.

Additional Power Supply Regulation

There are two analog power supply regulators on the A7 Midplane board
assembly. They are the +3.3V_A and -5.2V_A supplies.
The +3.3V_A supply is regulated down from the instrument +5.1V_A supply
while the -5.2V_A supply is regulated down from the -7V_A instrument supply.
Both of these supply voltages have test points and LEDs on the A7 Midplane board
assembly as seen in Figure 2-15.

Instrument Secure Storage

This is Non-volatile storage of instrument model number, serial number, and
software license keys. While the license keys are also contained on the C: drive of
the instrument, the model and serial numbers are only saved in this secure memory.
There is no way for the user to access this memory in any way. This is reserved for
the factory and field software when needed for instrument adjustments, as well as
the instrument software when installing an option license key. If for some reason
any of these cannot be remembered by the instrument there could be a problem
with this memory and the A7 Midplane board assembly would need to be replaced.

Power Supply Dithering

A triangle wave of approximately 100 Hz is generated and goes directly to the A6
64 Chapter 2