Tektronix WFM8200, Service Manual

Page: 53 / 85

General Maintenance
Table 4-6: Audio main board secondary supplies
Supply name Range Measured at
+1.5 V 1.425 to 1.575 TP6
+3.3 V 3.1 to 3.6 TP8
-5 V -4.5 to -5.5 TP9
+5 V 4.75 to 5.2 TP10
+1.26 V 1.20 to 1.32 TP11
+1.8 V 1.71 to 1.89 TP95
Check the secondary supplies on the Analog audio board, if installed. This is
the smaller audio card to which the 62 pin DSUB connector is mounted. The
test points are available, with the board installed, along the top front edge of the
board. (See Figure 4-3 on page 4-22.).
Table 4-7: Analog audio secondary supplies (board not present for option DS
instrument)
Supply name Range Notes
+15 V 14 to 15.5 TP901
–15 V –14 to -15.5 TP803
+5 VD 4.8 to 5.2 TP5
+5 VA 4.8 to 5.2 TP3
+3.3 V 3.1 to 3.6 TP2
–5 V –4.5 to -5.5 TP1
The Eye board also has multiple secondary supplies, and test points along the
top edge where they can be probed. The Power-up Diagnostics measure these,
so they are not included in this procedure. Note that some of these supplies are
only active in either SD or HD mode, so it is normal for some of them to not
be present in some operating modes.
Front Panel Button
Troubleshooting
Perform this test if the power supplies are good, but none of the buttons are lit
or respond to presses.
1. Cycle the power to the unit. Immediately after power on, three buttons
(GAIN, SWEEP, and MAG) should be lit continuously and the other buttons
should be lit one at a time in a walking pattern.
2. If the buttons are not lit, check the 10 pin cable from the keypad to the main
board J21. If the cable is connected and good then replace the front panel
assembly.
WFM8200 and WFM8300 Waveform Monitors Service Manual 4–13