No subject
Joseph W Lutz
joelutz at JUNO.COM
Tue Jan 20 00:55:58 EST 1998
August 1, 1974
HA-201 Bulletin No:
Walkie Talkie HA-201-1
Amplifier Instability
Differences in cable characteristics between suppliers cause some
amplifiers to oscillate.
The two T/R switch transformers [T1 and T2] should be cut to 17 1/2
inches long. This dimension will satisfy all 343-15 cables.
Future manuals will instruct the customer to cut to this new length
instead of 20".
-------------------------------------------------------------------------------------------------------------------
September 25, 1974
HA-201 Bulletin No:
Walkie Talkie HA-201-2
Instability Of The Drake TR-22/HA-201
Combination
To correct instability problems that may occur with the TR-22/HA-201
combination, install the following change:
Change:
Connect a 150 ohm resistor [PN 1-66] between the center pin and
ground lug at the RF INPUT connector.
Install this change only in HA-201 Amplifiers used with the TR-22
Transceivers and only in cases where instability occurs on
specific
operating frequencies.
-------------------------------------------------------------------------------------------------------------------
February 14, 1977
HA-201 Bulletin No:
Walkie Talkie HA-201-3
PN 417-803 Identification
++++Information not yet available++++
-------------------------------------------------------------------------------------------------------------------
May 21, 1981
HA-201 Bulletin No:
Walkie Talkie HA-201-4
Manual Correction For Q1
++++Information not yet available++++
--------------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1989 that covers the HA-201. Enjoy!
--------------------------------------------------------------------------------------------------------------------
February 23, 1973
HA-202 Bulletin No:
2 Meter Amplifier HA-202-1
Service Seminar
I. Output Transistors
1. Detecting Failure
a] Will not tune up to full power, one transistor may be
open.
b] Output trimmers fall beyond 1/2 turn from preset
[into 50
ohm load]. If non-ideal load is used, 1 turn
should be the
key denoting output failure.
c] Measure with ohm meter for shorted or open
transistor.
These transistors may check GOOD and still NOT
operate.
2. Replacement - The following sequence is important to prevent
damage to transistors.
a] Remove Transistor Nuts First - Be sure to hold the
tab
with a pliers.
b] Then remove the print board mounting screws.
c] Unsolder leads of transistor[s] & solder in new one
[s].
d] Install print board screws.
e] Install nuts on transistors. Be sure to hold the
flat tab with
pliers. Tension may break heat sink bond resulting
in very
sort transistor life.
3. Operates in Class C mode.
a] Ideal for FM. Not for AM or SSB [distortion
results].
II. Supply Considerations
A battery should be used. Tolerated voltages are between 12 and
16
volts. Expect the full load of 7 amps. If a battery eliminator
is used,
more than one-half volt P-P ripple will induce hum in the output.
III. Insertion Loss
Expect to experience loss of power when the amplifier is not
keyed up,
[low drive power].
1. The unit exhibits a 1.5 to 1 VSWR when not keyed up causing
any
wattmeter connected in the drive circuit to read
erroneously.
2. The higher VSWR while the unit is not keyed will cause the
output
of the driver to be slightly detune.
This VSWR will be lowered considerably when the units keyed
up
because the reactance will be tuned out of the drive line
by the input
circuit.
The power meter should be connected between the amplifier
output
and the dummy load. Any readings between the driver and
amplifier
can be misleading. Suggested reading: ARRL Handbook -
Transmission Lines.
IV. Load
High VSWR results in mistuning of the output trimmers.
1. Check for indications of arcs across the mica in the output
trimmer.
They must be replaced if any found.
V. Drive Considerations
Please avoid any usage outside of 5-15 watt specification.
Failure of the transistors may occur if too high.
The amplifier may not key up if power is too low.
VI. Mounting
Thermal conditions are always a consideration. Suggest not to be
mounted in engine compartment. Consider mounting low in the
trunk
allowing for the heated air to rise. The specs call for a range
of - 30 deg
F. to 140 deg F.
VII. Tuning Up
A slight additional power level can be achieved by tuning the
unit with the
cover ON. We will be providing a cover with holes in it for
service only.
DO NOT recommend to the customer to drill holes in HIS unit. The
cover
provides for a dust free environment which may help increase the
relay
contact life, among other things.
VIII. Connections
You may recommend, if desired by the customer, to change the
phono
connectors to BNC's.
SO-239 connectors exhibit a bump in the line. DO NOT use or
recommend these.
IX. Cables Supplied
All the specifications were measured using the full length of
cables
supplied. Do not expect any less performance because the full
lengths were used.
X. Schematic Error
The top condition of ferrite bead L8 goes to the collector of Q2.
NOT to
the junction of C11 and C12 as shown.
-------------------------------------------------------------------------------------------------------------------- November
16, 1973
HA-202 Bulletin No:
2 Meter Amplifier HA-202-2
Low Power Output [Less Than Driver Power]
Encountered unit which was drawing low current and had low output [less
than input power] upon measuring with PKW-3 [set up to measure more than
30 VR-F] it was found that the relay had a large [20V] drop across
terminals 4-3 when keyed. A couple quick "swipes" with a burnishing tool
cured this problem.
--------------------------------------------------------------------------------------------------------------------
September 26, 1978
HA-202A Bulletin No:
2 Meter FM Amplifier HA-202-3
Trimmer Capacitor Substitute
The first production run of the HA-202A will incorporate a substitute
trimmer [PN 31-52] at locations C1, C2, C15 and C16 due to unabailability
of the new type trimmers [PN 31-87] at this time. The second production
will incorporate the #31-87 trimmers. First production manuals will be
inserted [PN 591-2721] to instruct customer to use #31-52 trimmers.
It is not necessary to change the #31-87 trimmers, unless arcing is a
problem.
The #31-87 trimmers have a thicker mica insulator.
--------------------------------------------------------------------------------------------------------------------
July 30, 1979
HA-202 Bulletin No:
2 Meter FM Amplifier HA-202-4
Relay [PN 69-70] NLA
This relay is being replaced with [PN 69-91]. Since this isn't a direct
replacement, a modification kit [PN 830-37] has been made available at a
cost of $12.00.
The HA-202A Amplifier is already supplied witht he #69-91.
--------------------------------------------------------------------------------------------------------------------
Thats everything I hold up to 1989 that covers the HA-202. Enjoy!
--------------------------------------------------------------------------------------------------------------------
That completes the HA-XX series.
73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
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