HP 8903B - Page 164

Model 8903B
Special
Function
1.11
Service
TROUBLESHOOTING---SERVICE SHEET 1
Increase in Amplitude Level (TTL) at U15B Pin
Oscilloscope Limits
Vertical Gain (div PPI
9, 11 7, 13
x1 1.9 to 2.1 H H
1.15
1.17
1.19
xl 4.7 to 5.3 H L
xl 0 1.2 to 1.3 L H
x10 1.9 to 2.1 L L
7. Using a tee adapter, connect the HIGH OUTPUT to the HIGH and LOW INPUTS in parallel. Key in
AMPTD 1 V. The waveform on the oscilloscope should have an amplitude less than 50 mVpp. (The waveform
may
be non-sinusoidal.)
Hint: If the signal is only sIightIy out of limits, perform the Common-Mu& RLjt'c./ion A djirJtmenf, paragraph 5-9.
8B-19