Tektronix WFM700 Series, Service Manual

Page: 170 / 194

Troubleshooting
4- 36
WFM700 Series Waveform Monitors Service Manual
This troubleshooting tree is the second LED fault troubleshooting tree. Typically
perform the LED Fault Troubleshooting Tree 1 prior to this tree unless directed
here by other procedures.
Power on the
instrument.
Do the
ON/STBY and FAULT LEDs
indicate a momentary fault
or power supply fault (refer
to LED Fault Codes)?
Yes No
Yes
This indicates that the power supply voltages are not at
the required level. Causes could be a faulty power supply
or disconnected cable from the power supply module to
the Main Interface board. An overload condition causes
the power supply to shut down. Check that the cables
from the power supply module are properly connected
and are not damaged.
No
Remove installed modules from slots 1
through 6 and check for bent connector pins
on the Main Interface board.
Is the
fault condition
cleared?
Replace each module one
at a time to identify the
faulty module.
Disconnect and remove the Front Panel assembly.
Use a jumper to momentarily connect the two pins of
J592 (RELAY ON) together on the Main Interface board.
Yes
No
Is the
fault condition
cleared?
Replace the Front
Panel assembly.
Are
all power supply LEDs
on the Main Interface
board dark (DS460,
DS470, DS471,
DS472)?
No
Disconnect the large power supply cable
from the Main Interface board at J270.
Do the
+12 V and --12 V LEDs
(DS471, DS472) light
during power up?
Yes No
Yes
Replace the Power
Supply module.
Check Main Interface board for
debris, bent pins, or other foreign
objects causing a short circuit.
Replace Main Interface board if
no visible problems are found.
If problems persist, refer to
Check for Problems on
page 4--27.
If problems persist, refer
to Check for Problems
on page 4--27.
Figure 4- 15: LED fault troubleshooting tree 2
LED Fault
Troubleshooting Tree 2