Tektronix 2A60 Instrument Reference Book page 47

VARIABLE VOLTS/DIV RATIO
ASSURED BY CHANGING
R474-R476 TO HIGHER VALUE
Effective Prod SN 3044
w /exceptions: 3041-2
FRONT PANEL SYMITOM: None.
INFORMATION ONLY
Ml0303-2
PROBLEM: Unable to meet 11. 1 VARIABLE VOLTS/DIV specification when R475 is selected
at the low end of its allowable range (39 O).
PRODUCTION CHANGE: R474 and R476 in the cathode circuit of the output amp V474 were
changed from 4. 7k to 5.1 k resistors. See Mll2l4o
Parts Removed:
R474, R476
Parts Added:
R474,R476
Res, 4. 7 k 1 W 5%
Res, 5 o 1 k 1 W 5%
6AU6 AND 12AU6 TUBES REPLACED BY
PREMIUM 8425 AND 8426 TUBES TO
REDUCE MICROPHONICS, INTERFACE
AND GRID CURRENT PROBLEMS
Effective Prod SN 3300
INFORMATION ONLY
FRONT PANELS SYMPTOM: Microphonics, interface, and grid current.
303-0472-00
303-05)2-00
Ml0548
PROBLEM: Usage of 6AU6 and 12AU6 tubes results in high reject rate and length of
selection time because of microphonics, interface, and grid current.
PRODUCTION CHANGE: Type 6AU6 and 12AU6 tubes were replaced by 8425 and 8426
premium tubes.
Parts Removed:
Parts Added:
1-31-67
V434, V444
V434, V444
Tube, raw 6AUS
Tube,raw 8425/6AU6
60/2A60 MODIFICATION SUMMARY
154-0022-00
154-0022-07
Page 11