Fluke 8062A Instruction Manual page 85

Table 4-6. Troubleshooting Guide (cont)
Test and Symptom
Power Supply (cont)
VDG (voltage between
TP7 and TP8)
3.15 0.08V
VSS (voltage between
TP2 and common)
-5.1 0.27V
TP4 1.225 0.025V
U3-11 1.0000 0.0004V
Voltage Test - DC
Gross error (constant
reading of 0.00 or OL)
Ratio self-test passes,
but constant reading
of 0.00
Possible Cause/Suggestions
U3, C12, U5
U4, C21, C23
Hint: if you suspect U3 power
supplies are bad, you can drive the
8062A power supplies externally.
Remove battery, C pcb, and U3.
Apply +5.2V at TP1
check the ac converter, diode test
source, VR2, U4, and the power
supply circuitry.
Perform ratio self-test in dc volts. If
count is good, U3 is good. If count is
way off, suspect U3, C9, R33, R8,
Z3, C16 or C18
R1, R2 (fusible resistors
with exact equivalent only). RJ1, RJ2,
RJ3, RJ4 (varstors turn yellow when
shorted), open circuit in front end,
bad component is input divider, U3
pins 6 and 7 shorted. (Hint: check
high impedance dc voltage first,
which bypasses the input divider.)
Refer to Table 4-1 for input divide
ratios.
Maintenance
Troubleshooting
you can then
replace
4
4-23