Secondary Interface Troubleshooting; Voltage And Current Dac - HP 6033A series Service Manual

+5V and PCLR Circuits:
Node Measurement
≈ 3.5Vdc
U1-8
U1-2 = 4Vdc
U1-3 = 4.2Vdc
U1-4 = 4.2Vdc
≈50mVdc
U1-6
Clock Signals (see clock waveforrns in Figure 3-3)
Node
C7+,C8+ = 12MHz (see waveform)
J5-8 = 6MHz (see waveform)
≈ 50mVdc (see waveform)
U35-12
Data Lines Check that all data and address lines are toggling. Address and data lines go to the following IC's:
Address Lines
U6: A0 to A15
U8: A0 to A15
U12: A0 to A4
U14: A8 to A15
U16: A0 to A7
U17: A0 to A2
U36: A7 to A15
Note:
Data and address lines may not toggle if one line is shorted either high or low. If no short is found, replace
all socketed IC's. If the data lines still do not toggle, replace the HP-IB (A8) assembly.
Node Measurement
A0 to A15 Toggling
D0 to D7 Toggling

Secondary Interface Troubleshooting

Secondary interface troubleshooting checks the operation of the voltage, current, and readback DACs as well as analog
multiplexer and secondary microprocessor. The analog multiplexer is checked in the Readback DAC troubleshooting
procedure. The secondary microprocessor can only be checked using secondary SA (refer to Signature Analysis).

Voltage and Current DAC

The voltage and current DACs can be checked either from the front panel or by secondary SA. Refer to Signature Analysis
to troubleshoot the voltage and current DACs in this manner.
Note:
To troubleshoot the voltage and current DACs from the front panel if the unit has failed selftest, place
jumper A8J5 in the skip selftest position (see Table 3-2). This lets you operate the unit even though it fails
the internal selftest.
Use the front panel controls to vary the output voltage and current from zero to full-scale output. Remember to turn off the
unit and connect a short across the output before programming the current from zero to full scale. Use a DMM and check
the voltages at the following nodes:
38
Measurement
Data Lines
U6: D0 to D7
U8: D0 to D7
U12: D0 to D7
U14: D0 to D7
U16: D0 to D7
U17: D0 to D7
Source
Y2
U14
U35