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AST RESEARCH TECHNICAL BULLETIN TB-0005 4-23-84
SETTING CLOCK FREQUENCY FOR SIXPAKPLUS FASTER OR SLOWER
CAUTION: We suggest that you leave the factory configuration
alone. But, if you must, here is the pertinent
information you'll need.
How to set frequency of SixPak clock, so as to slow frequency
down or speed frequency up.
First, a few points of reference:
1. Clock chip U66 on SixPak board, pin 11 is the pin
responsible for checking frequency (see Diagram 1.0).
The notched end of the chip is the location of pin 1
(see Diagram 1.1).
2. Variable Capacitor; C86 located next to clock chip (see
Diagram 2.0). Turning this clockwise speeds up frequency
and turning counter-clockwise slows it down (see Diagram
2.1).
The recommended frequency range is 30.5171-30.5175KHZ.
Above 30.5175, or clockwise, is faster; and below
30.5171 KHZ, or counter-clockwise, is slower (see
Diagram 2.2).
3. Setting Frequency Counter: Racal-Dana 9906 or
Equivalent.
A) Time Base 104
B) Period A
C) Delay Out
D) DC
E) Start and Stop on Leading Edge
4. Checking voltage of battery pin 24 of clock chip and
minus side of battery holder (see Diagram 3.0).
Minimum voltage at pin 24 should be no lower than 2.3
volts, and the battery itself should be 3.0 volts; 2.8
at the lowest.
NOTE: As a portion of the data is in pictorial form, it is not
included here. To obtain a complete copy of this technical
bulletin, contact:
AST RESEARCH, INC.
2121 Alton Avenue
Irvine, California 92714
ATTENTION: Product Support
(Technical Bulletin)