Heathkit SG-8 Manual page 20

(2) Connect an output indicator to the receiver. This may be an AC voltmeter connected di-
rectly across the loudspeaker voice coil; however, a VTVM connected tomeasure AVC vol-
tage is by far the most desirable method.
(3) Short out the local oscillator tuning circuit temporarily. The simplest way to accomplish
this is merely by clipping a short piece of wire across the rotor and stator plates of the
oscillator section of the tuning condenser. Set the receiver dial to the low frequency end,
somewhere near 550 KC.
(4) Connect the signal generator to the antenna terminals of the receiver or if the receiver
employs a loopantenna or rod antenna, couple the output of the generator to the antenna sys-
tem through a one or two turn loop of wire around the antenna. In cases where an RF stage
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stage. Set the signal generator to the IF value of the set. (455 KC is generally the accepted
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An unmodulated signal is used provided the AVC voltage is used a
(5) Using the lowest range of the output indicator, increase the output of the signal generator
until a reading can just be obtained
(6) Adjust the IF transformers for maximum reading on the output indicator. Reduce the sig-
nal generator output as necessary to keep a lowreading on the output indicator. Repeat the
adjustments at least once to correct for any interaction between primary and secondary
windings on the individual transformers. Interaction is most likely to occur in sets where
adjustment is by means of iron-core slugs rather than trimmer condensers.
(7) Next, remove the short across the local oscillator and tune the receiver to its highest fre-
quency setting (somewhere around 1600 KC). Set the signalgenerator to the same frequency
and adjust the oscillator trimmer for maximum output.
(8) Now tune the receiver and signal generator to 1400 KC and adjust the RF trimmer for max-
imum output.
(9) Turn the signal generator to 600 KC and tune the receiver to the low frequency end of the
dial. Now "rock" the receiver tuning condenser while at the same time adjusting the trim-
mer condenser for maximum output. in sets using especially shaped pilates inthe oscillator
section of the tuning condenser, generally no trimmer condenser will be found. Also, in
some sets, the low ir equency oscillator adjustment will be through means of an iron-core
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The alionment procedure for multi-band AM superheterodyne receivers is essentiany the same
as Outlined above fora single-band set. First the IF stages are alignedusing the same technique
as given in Steps through 6. Next, each RF band is sae 1ed separately, starting with the high-
If the oscillator and RF trimmer condensers for the different bands are not well identified, a
simple technique may be employed to locate the proper adjustment screws. Turn the receiver
band switch to the highest frequency band and tune in a signal, using a short-wave station or a
signal from the RF generator.
Using an insulatedalignment tool, try compressing the different
oscillator trimmers until one is found that changes the tuning of the signal. Do not compress
the oscillator
trimmer condensers by turning the adjustment screws,
just press the leaves of
the condenser together temporarily. This method will identify the trimmers for each band with-
out drastically changing their original setting.
After identifying the oscillator trimmer for the
band in this manner, repeat the technique to identify the RF trimmer. Turn to the next band
and repeat the method, being careful not to touch the trimmers already identified.
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