REV DEC 1986
The maintenance aids listed in Table 6-5 include items
required for performing most of the maintenance pro-
cedures in this instrument. Equivalent products may be
substituted for the examples given, provided their charac-
teristics are similar.
MAINTENANCE AIDS
Tektronix Part No.
321-0222-00
321-0277-00
321-0233-00
321-0235-00
321-0236-00
Value
2.0 kfl
2.26 kfl
2.61 kfl
2.74 kfl
2.8 kfl
Selectable resistors for A11R767/A11R867 and
A11R679/A11R878 resistor pairs are:
After replacement of the resistor pair(s), repeat the
linearity check.
If
the instrument still fails that check,
change the resistor pair of the affected channel(s) to the
next higher value in the list. Repeat the check, changing
the resistor pair(s) to the next higher range until the
affected channel(s) pass the linearity check. This method
for resistor pair selection insures the lowest value allowing
the instrument to pass the LF linearity test is used. Using
the lowest possible value for the resistor pair prevents
other performance characteristic from being compromised.
If the instrument is outside the tolerance limits for the
linearity check, the resistors should be changed to the
next higher value in the following list. Change only that
resistor pair for the out-of-limit channel, unless both chan-
nels fail the linearity check. Always replace both resistors
in the pair with the same value resistor.
Selection of A1OR767 and A1OR867 may be necessary
if the CH 1 CCD (U450) is changed; selection of R679 and
R878 may be necessary if CH 2 CCD (U350) is changed.
These resistor pairs affect the gain of their associated
CCD. To determine if resistors require selecting, perform
"Check LF Linearity," Step 4 of the Performance Check
procedure in this manual. If the instrument passed this
check, no resistor change is necessary.
Do not increase the value of the resistor to the point
where the bandwidth and rise-time performance require-
ments are not met; the
±
6%, 6% peak-to-peak guideline
is maintenance information only, not a performance
requirement. The bandwidth, rise time, and aberrations
should be measured with the affected channel set to
200 mV per division.
6-12
3. The change in front-corner aberrations for changing
the resistor is less than or equal to 1%.
2. Decreasing the resistance increases bandwidth and
rise time while increasing front-corner aberrations.
1. Increasing the resistance reduces the front-corner
aberrations while decreasing bandwidth and rise time.
It may be necessary to select A1OR1015 if the CH 1
Preamp (U420), Peak Detector (U440), and/or CCD/Clock
Driver (U4~0) is changed. Selection of A1OR1016 may be
necessary If the same components associated with CH 2
(U100, U340, and U350, respectively) are changed. Upon
changing any of those components, the vertical perform-
ance checks associated with the affected channel should
be made. If the bandwidth and rise time performance
requirements are met and the front-corner aberrations are
within approximately
±
6% and 6% peak-to-peak, the
resistor associated with the affected channel should not be
changed. If these conditions are not met, selecting the
resistor changes circuit response as follows:
Specifically, selected components are A1OR767.
A10R867. A10R679, A10R878, A10R1015. and
A1OR1016. All the components are located on the Main
board. Resistors A10R1015 and A10R1016 are shown on
schematic diagram 9, while the remaining resistors are on
schematic diagram 14.
Several components in the 2430 are selectable to
obtain optimum circuit operation. Value selection of these
components is done during the initial factory adjustment
procedure. Further selection is not usually necessary for
subsequent adjustments unless a component has been
changed that affects circuitry for which a selected com-
ponent has been specifically chosen.
SELECTABLE COMPONENTS
4. Tektronix part number.
3. A description of the part (if electrical, include its full
circuit component number).
2. Instrument serial number.
1. Instrument type (include modification or option
numbers).
Ordering Parts
When ordering replacement parts from Tektronix, Inc.,
be sure to include all of the following information:
Maintenance-2430 Service
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