- Transmitter ALC levels may be increased by these optional component changes. Check for correct component values when installing the CK-18 kit.
On the LPF Unit X51-1180-00 change:
C14 from 470pf to 390pf (CM93D2H391J)
C17 from 470pf to 390pf (CM93D2H391J)
18 and 21 MHz
C25 from 27pf to 39pf (CC45CH2H390J)
C26 from 82pf to 68pf (CC45CH2H680J)
C28 from 82pf to 120pf (CC45CH2H121J)
C29 from 27pf to 39pf (CC45CH2H390J)
24.5 and 28 MHz
C30 from 18pf to 39pf (CC45CH2H390J)
C34 from 18pf to 39pf (CC45CH2H390J)
All capacitors should be 500V silver mica or disc ceramic, 5%.
ALC Adjustment. After these component changes, perform ALC alignments 4-4,
4-5, and 4-6 as listed in the Service Manual. Be sure to adjust to spec.;
incorrect meter zero (4-4), output exceeding 95W (4-5), or failure to peak
T1 (RF unit) and L15 (IF unit) (4-6) will result in low or no ALC and
possible future damage to the power amplifier.
Fast protection with a linear amplifier. While working in the LPF
unit, check the value of C73 (base of Q1). If it is 1uf, change to a 3.3
uf @ 25v dc tantalum (CS15E1E3R3M). This will compensate fro slow linear
amplifier relay closure.
These changes are at the owners option and may not be performed in