Tektronix TLA Series, Service Manual

Page: 111 / 130

Troubleshooting
TLA Series Digitizing Oscilloscope Modules Service Manual
6- 33
Approximate
Signal resistance to ground
Values shown are typical when using a Fluke
8842A DMM on the 2K scale. Allow the meter to
stabilize for 10 seconds before reading the
measured value.
DATA2
--15 V
--5 V
OFFSET
CLOCK
+5 V
+15 V
DATA1
Clock 1 kW
+5 V 20 W
+15 V 590 W
Data1 950 W
Data2 950 W
--15 V 150 W
--5 V 30 W
Offset 870 W
Figure 6- 16: Probe interface resistance
Table 6--6 can help you isolate problems to one of the two circuit boards in the
module (use the
Removal and Installation Procedures beginning on page 6--7 to
replace the faulty circuit board).
NOTE
. If there are a majority of Acquisition items failing or the system can’t find
a unit, the problem may be a Processor Board or a ribbon card failure.
Table 6- 6: Diagnostic tests
Group & test Most likely cause Power on Extended
Kernel
Power-On Kernel MPU
n n
MPU Static RAM MPU
n
Nonvolatile RAM MPU
n
DSP Shared RAM MPU
n
VXI Shared RAM MPU
n
Calibration Checksums MPU; ACQ
n n
Factory Calibration Status Recalibrate with
CATS; ACQ
n n
Diagnostic Tests Table