a) Disconnect the AC power cord.
b) Disconnect J3203 from the circuit board.
c) Connect the AC power cord.
d) Measure for +12 V
DC
between pin 10 (+12 V
DC
) and pin 18 (ground) on the disconnected cable.
If there is no +12 V
DC
value on pin 10, carefully check for 115 V
AC
at the connectors of the AC line filter. If there is
AC at the line filter, replace the power supply module or reassemble and return the instrument to a Tektronix Service
Center for repair.
Warning: Be careful when measuring the AC line voltage to avoid injury to yourself or damage to the
instrument.
3. If there is +12 V
DC
at pin 10 of the disconnected J3203 cable, do the following:
a) Disconnect the AC power cord.
b) Reconnect J3203 to the circuit board.
c) Connect the AC power cord.
d) Insert for one (1) second and then remove a 0.1-inch-spaced shorting jumper between pins 9 and 10 of the Service
connecter pins on the edge of the circuit board (see following image). Wait five (5)seconds as the fans turn on and
the power supply powers on.
Maintenance
6 Series B MSO MSO64B, MSO66B, MSO68B Service
23
