Tektronix T921 - Page 77

SHORT METAL CONTACT
(INSIDE BOOT) TO 3/16
INCH POST
7 .
Remove crt socket .
SHORT OUTPUT OF
HIGH
VOLTAGE MULTIPLIER
TO CHASSIS
WITH
A
PIECE OF INSULATED WIRE
Fig . 5-12 . T922R
interface
board replacement .
REMOVE 3
PLASTIC
SCREWS FROM
TRAN-
SISTORS, DURING AS-
SEMBLY, CHECK FOR
A SHORT FROM
THE
METAL TAB ON
THE
TRANSISTOR TO
THE
CHASSIS . IF SHORTED
THE POWER FUSEWILL
BLOW .
OUTPUT OF
HIGH-VOLTAGE
MULTIPLIER
1982-58
8 . Make note of their location to aid reassembly, then
disconnect all harmonicaandmolex connectors from the
interface board . Don't forget to disconnect the vertical crt
leads and quide them through the holes in the interface
board .
9 . Remove the screws and posts from the interface
board (see Fig . 5-12) .
10 . Lift the interface board out of the instrument .
11 . During reassembly, use the plastic screws to hold
the power transistors (see Fig . 5-12) .
Power Module Replacement
1 . Remove the plastic shield covering the power
module .
ServiceInformation -T921/T922/T922R
2 . Remove P7 from the powermodule .
3 . Remove two screws and two bolts from the power
module (see Fig . 5-13) .
4 . Lift the power module away from the instrument .
Buffer Board Replacement
1 . To aid in reassembly, make note of the positions of
the harmonica connectors on the buffer board . Then,
disconnect the harmonica connectors from the buffer
board .
2 . Remove the four screws from the buffer board .
CRT Replacement
NOTE
You don't need to remove the switch extensions to
remove the buffer board .
3 . Slide the buffer board toward the rear of the
instrument to remove .
1 . Remove the four screws from the left side rail and
remove the side rail .
2 . Remove the
four screws
from the high-voltage shield
and lift the shield away from the instrument .
THESE SCREWS
HOLD
TRANSFORMER
TO
BOARD . NO NEEDTO
LOOSEN THEM-
Fig . 5-13 . T922R power module replacement .
5-1 9