Keysight 41800A Active Probe
61
Service
Theory of Operation
Theory of Operation
The 41800A active probe consists of amplifiers and regulators. The amplifiers
provide unity gain. The amplifiers are on the PC board/Heatsink assembly and
the Amplifier/Regulator Board assembly.
The regulators convert the DC voltage (+15 V and –12.6 V) supplied from the
host instrument, and supply the regulated DC voltages (+15 V, +9 V, –7 V, and
–12 V) to the amplifiers. The regulators are on the Amplifier/Regulator Board
assembly.
Troubleshooting Guide
Troubleshooting should be begin during the performance test. If the 41800A
fails the performance test, perform the following procedure.
1. Check the voltage supplied by the host instrument. Refer to
“Probe Power Requirements” on page 13
for the required voltage.
2. Check the probe tip for damage. If the probe tip is defective, replace the
probe tip.
3. Confirm that the gain of the PC board/Heatsink assembly is approximately
–6 dB. The probing point is shown in
. If the gain is wrong,
replace the PC board/Heatsink assembly.
Figure 6-10
PC Board/Heatsink Assembly Check
