Ameco PT - Alignment Procedure; Replacement of the Fuse;Resistor; Parts List

t.
ALIGNMENT
PROCEDURE
The
preamplifjer
in the
PT
has no adjustments.
All
tuning is done by
the variable
con-
denser.
Cl
'is
a
reactance cancelling
capacitor
which'is
used
to reduce
the SWR
to less
than
l.l:l
The
adjustment
procedure
is
as follows:
l.
Connect
a transmitter
to
a
standing
wave bridge.
2.
Connect the
PT Pl to
the bridge.
3.
Connect
a
good
50 ohm dummy load
(such
as. Bird,
Sierra,
etc.)
to the PT
Jl.
4. Short PT PZ during this whole test,
the
power
MUST
be
on the
PT.
5. Tune up
the transmitter
on 52 MHz
if
ava'ilable,
otherwise
on the
h'ighest frequency on
the
transmitter.
Use
35
watts
minimum.
6. Switch
to
read reflected
power.
7. Adjust
C1
for
a
mjnimum
reading.
Do not disturb Cl except
in the complete
procedure
above.
REPLACEMENT
OF
THE FUSE/RES|STOR
To replace fuse/resistor
R10,
use only Allen Bradley
or
0hmite carbon
composit'ion,
l/1O-watt
size.
Do not use l/4-watt
or
deposited
carbon resistors
as they will not
break
quickly
enough.
Unsolder
the
remains of the
broken
res'istor
from
the
lug and
the spring
wire.
Solder one
end of
the
rep'lacement
resistor
to the
terminal
lug. Hook
the other end
oVei
ttre spring
wire and
pu11
the
lead until
the
spring is
-dEiieeted
about 1/16 inch.
hlh'ile
holding this
position,
solder
the
resistop
lead
to the spring wire.
Before
unsoldering
diodes
CR2
and
CR3,
check with an
ohmmeter.
Diodes are
good
if
the reading
is
.l00
ohms or less
jn
e'ither
polarity.
If
the
reading
is
high
in one
pol
ari
ty,
repl ace the two
d'iodes
wi
th type
'l
N281
on1y.
PARTS LIST
Most
components
used
in th'is
unit
are
available as over
the
counter items at any
radio
parts
supply store. Listed
below, are
specia'l items
that
are obtainable from AEROTR0N
on1y.
ITEM
DESCRIPTION
PART
NO.
R10
CR2
CR3
K1
LI
L2
L3
L4
S2
TI
T2
100 ohm,
t70%,
7/10 watt,
comp.
Diode, I N28l
D'iode
,
I
N28l
Re"lay, 4PDT, I l0 VDC coi I
Cojl,
l.B-4 MHz
Coil,
4-.l0 MHz
Co'il,
l0-23 MHz
Coi1,
23-54 lt1z
Swjtch,
rotary, 2
po1e,
4
posjtjon
Transformgr, Toroid
Transformer,
Power
47a5
loo3
oor
4804
0000 006
4804
0000 006
4507 0000 002
lB20 l615 021
I 820 1 615 022
tB20 t6t5
023
1805 I 615 024
5ll0
0000 017
5649 I 601 A25
56.1
0 0000 0t 9
2.
3.
4.