11. Dc Resistance of Transformer T1
The
dc
of
the
windings
of
transformer
T1
are
listed
below.
Ohms
Winding color code.
Winding
8
Black, black-yellow
Primary No. 1
8
Black-green, black-red
Primary No. 2
less than 1
Brown, brown
6.3-volt filament
less than 1
Yellow, yellow
5-volt filament
105
Red, red-yellow
Hv and center tap
210
Red, red
Hv (end to end)
0.18
Green, white
9-volt filament
0.12
Green, red
6.3-volt filament tap
Section Ill. REPAIRS AND ADJUSTMENTS
12. General Parts Replacement Techniques
into the pats on the chassis; they may
cause short circuits.
f. A carelessly soldered connection may
Most of the parts of the rf amplifier
c r e a t e new faults. Make well-soldered
can be reached and replaced easily Without
joints; a poorly soldered joint is one of
s p e c i a l procedures. The following pre-
the most difficult faults to find.
cautions apply specifically to the rf am-
g. Replace all parts in exactly the same
plifier:
position occupied by the original part. Use
a. When servicing the chasms assembly,
e x a c t replacement parts if possible; a
d o not disturb the settings of variable
p a r t that has the same electrical value
r e s i s t o r R6 (gain adjust), variable ca-
b u t different physical size may cause
pacitor C11 (which controls frequency re-
trouble.
sponse), or variable resistor R27 (which
h. Give particular attention to proper
adjusts the dc voltage for the filaments
grounding when replacing a part; use the
of V1 and V2).
s a m e ground as in the original wiring.
b. Before a part is unsoldered, note the
Failure to observe the precautions may
position of the leads. If the part, such as
result in undesirable voltages being pro-
the power transformer, has a large num-
duced when the rf amplifier is operated
ber of connections, tag each lead.
with other test equipment.
c. Do not damage the leads by pushing
or pulling them out of the way.
13. Power Supply Adjustments
a. Regulated Output Voltage. Whenever
when soldering small parts. Irons of less
than 50 watts are recommended for sol-
electron tube V5, V6, or V7 is replaced,
d e r i n g this equipment. Overheating of
c h e c k the regulated output voltage as
small parts may damage or change the
follows:
value of the component.
(1) Connect the rf amplifier to a suit-
a b l e power source (115 or 230
14
