HP 8112A Operating, Programming And Servicing Manual page 239

6. Observe the main output using an oscilloscope and check the
leading and trailing edges for distortion.
7. If there is distortion, check the output-amplifier input signal at
TP4. Then do the following:
a. Set up the HP 8112A as follows:
HIL
b. If the input signal is clean but the leading edge of the output
signal is distorted, check Q503 and Q505.
c. If the trailing edge is distorted, check Q504 and &SOS.
Servicing the Shaper and Output Amplifier
-8.0 v
10.4-15