Heathkit Service Bulletins - SB-3XX (Complete)
Joseph W Lutz
joelutz at JUNO.COM
Mon Jan 19 22:48:18 EST 1998
July 28, 1978
SB-300 Bulletin No:
SSB Receiver SB-300-1
Intermittent IF Oscillation
If the Mode switch shaft is not grounded properly, it can cause capactive
coupling between the input and output stage switch wafers for the IF
amplifier.
Check for loose setscrews in the shaft coupler near the Mode switch
detent. Retighten if necessary.
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July 28, 1978
SB-300 Bulletin No:
SSB Receiver SB-300-2
LMO Drift; Intermittent Frequency Shift
Check for a dirty or corroded phono conector on the rear of the LMO.
Clean if necessary.
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Thats everything I hold up to 1989 that covers the SB-300. Enjoy!
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November 1, 1967
SB-301 Bulletin No:
Ham Receiver SB-301-1D
LMO Change
Change: LMO from [PN 110-32] to [PN 110-40].
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July 24, 1978
SB-301 Bulletin No:
Ham Receiver SB-301-1
LMO Drift; Intermittent Frequency Shift
Check for a dirty or corroded phono conector on the rear of the LMO.
Clean if necessary.
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Thats everything I hold up to 1989 that covers the SB-301. Enjoy!
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November 25, 1970
SB-303 Bulletin No:
Ham Receiver SB-303-1
SB-303 Operation With SB-610 Monitor Scope
Envelope monitoring with the SB-610 is satisfactory with the SB-303.
Using the 1.0 uF coupling capacitor provided, approximately 1/4"
peak-to-peak deflection is obtained with an S-9 signal. Connection is
made to the collector of Q503, 3rd IF Amp. on the IF/Audio board.
Retuning of [PN 52-125], T-503, is not required. However, should more
deflection be required, a larger capacitor could be used and would
probably require a slight retuning of T-503.
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November 25, 1970
SB-303 Bulletin No:
Ham Receiver SB-303-2
SB-303 Operation With SB-620
Scanning operation of the SB-620 is satisfactory with the SB-303
receiver. Connection is made to the drain of the 2nd Mixer, Q204 on the
Mixer board with the 7.5 pF capacitor provided. Retuning of L-202 does
not appear necessary unless AGC is removed and a signal generator used
for alignment. AGC does have, of course, an effect on the SB-620 display
amplitude.
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December 28, 1970
SB-303 Bulletin No:
Ham Receiver SB-303-3
FET
Since performance can vary a great deal with the variation in tolerances
of the 40673 FET, a permanent change is being made.
Change: [PN 417-240] 40673 FET to [PN 417-274] RCA 40673 FET.
Note: PN 417-217 Specifies RCA as the vendor and also calls for tighter
specifications.
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August 14, 1973
SB-303 Bulletin No:
Ham Receiver SB-303-4
Intermittant Connections Of The IF-Audio
And BFO-Power Supply Boards
Installing spacers [PN 255-1] between the chassis and connector mounting
plates reduces spacing between board connectors & chassis connectors.
This assures a much tighter connection and allows a better orientation of
switch wafers to shafts, etc.
The #6-1/4" smet screws are to be replaced with #6-3/8" smet screws - 12
required.
Threaded press-in standoff spacers will appear in production when parts
are available.
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January 11, 1974
SB-303 Bulletin No:
Ham Receiver SB-303-5
Instability
Oscillations [audio] can be cured by tinning the edges of IF and BFO
circuit boards to improve grounding.
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May 23, 1974
SB-303 Bulletin No:
Ham Receiver SB-303-6
Signal Input Checks For SB-303 Receiver
Equipment Needed- - -
VTVM
RF Signal Generator with 3db pad
Audio Generator
Set Controls To Positions Indicated---
Function - Operate
Converter - H.F.
Preselector - 10 o'clock
R.F. Atten - Fully CW
Band - 3.5
Main Tuning - 0.00
AGC - Fast
R.F. Gain - Fully CW & pushed in
Mode - USB
A.F. Gain - 12 o'clock
Connect VTVM and set to 5 volt A.C. range across 8 ohm speaker. Set
audio generator for 1 Khz and connect to points indicated.
INPUT POINT INPUT LEVEL VTVM READING
Base of Q509 .25 Volts 2 volts
Base of Q507 .2 Volts 2 volts
(P=E[SQD]/R ) P=4/8 = 1/2 watt
REMOVE AUDIO GENERATOR AND CONNECT RF SIGNAL GENERATOR AT POINTS
INDICATED.
Use a .005 MFD capacitor for isolation.
FREQUENCY INPUT POINT INPUT LEVEL S METER READING
3395 Khz Base of Q503 25000
Microvolts S-9
3395 Khz Base of Q502 3000
Microvolts S-9
3395 Khz G1 of Q501 1000
Microvolts S-9
8895 Khz G1 of Q204 700
Microvolts S-9
3500 Khz G1 of Q203 300
Microvolts S-9
3500 Khz G1 of Q101 30
Microvolts S-9
3500 Khz **Antenna 15
Microvolts S-9
Check RF voltage at points indicated [RF probe needed]
BFO out - .45 volts
HFO out - 1.5 volts
Q203 G2 - .6 volts
Q204 G2 - .3 volts
**Remove .005 MFD Capacitor
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January 6, 1975
SB-303 Bulletin No:
Solid State Ham Receiver SB-303-7
Parts Obsolescence
PN 417-105 will be replaced by PN 417-133 in this kit.
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October 22, 1975
SB-303 Bulletin No:
Solid State Ham Receiver SB-303-8
Circuit Breaker Screw Strips Out
Before replacing the circuit breaker because the threads have been
stripped, try using a slightly larger screw, [PN 253-55] to secure the
breaker.
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March 4, 1976
SB-303 Bulletin No:
Solid State Ham Receiver SB-303-9
Crystal Oscillator Fails To Start
This problem can be corrected by installing the following change:
Change: Q102 from [PN 417-133] to [PN 417-172].
The replacement 417-172 transistor is a 3-lead plastic-case device,
whereas the 417-133 is a 4-lead Metal case transistor so be sure the
transistor leads are installed in the correct holes.
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Thats everything I hold up to 1989 that covers the SB-303. Enjoy!
--------------------------------------------------------------------------------------------------------------------
August 14, 1973
SB-313 Bulletin No:
SWL Receiver SB-313-1
Intermittant Connections Of The IF-Audio
And BFO-Power Suppy Boards
Installing spacers [PN 255-1] between the chassis and connector mounting
plates reduces spacing between board connectors & chassis connectors.
This assures a much tighter connection and allows a better orientation of
switch wafers to shafts, etc.
The #6-1/4" smet screws are to be replaced with #6-3/8" smet screws - 12
required.
Threaded press-in standoff spacers will appear in production when parts
are available.
--------------------------------------------------------------------------------------------------------------------
January 11, 1974
SB-313 Bulletin No:
SWL Receiver SB-313-2
Instability
Oscillations [audio] can be cured by tinning the edges of IF and BFO
circuit boards to improve grounding.
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August 6,1974
SB-313 Bulletin No:
SWL Receiver SB-313-3
Lack Of Heterodyne Oscillation On 21.3 Mhz Band
Some SB-313 field units have exhibited oscillator starting problems on
the 21.3 Mhz band. This can be resolved with the addition of a 10 pF
disc ceramic capacitor [PN 21-3] across the 30.195 Mhz crystal Y109.
------------------------------------------------------------------------------------------------------------------
March 25, 1975
SB-313 Bulletin No:
SWL Receiver SB-313-4
No Reception
The wafer switch [PN 63-615] used on the Antenna Switch board has been
shipped with the wrong type lug installed at lug 7 of wafer B; rear. A
standard type lug was used in this lug not being connected to foil "E".
These switches can be used by connecting a jumper wire between lug 7 of
the switch and foil "E".
Quality Assurance was notified and all defective PN 63-615 switches were
removed from factory stock.
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June 6, 1975
SB-313 Bulletin No:
SWL Receiver SB-313-5
Bulb Obsolescence
The frosted lamp [PN 412-20] is no longer available. If replacement is
necessary, use a clear #47 lamp [PN 412-1] with a frosted cap [PN
413-39].
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October 22, 1975
SB-313 Bulletin No:
SWL Receiver SB-313-6
Circuit Breaker Screw Strips Out
Before replacing the circuit breaker because the threads have been
stripped, try using a slightly larger screw, [PN 253-55] to secure the
breaker.
-----------------------------------------------------------------------------------------------------------------
March 4, 1976
SB-313 Bulletin No:
SWL Receiver SB-313-7
Crystal Oscillator Fails To Start
This problem can be corrected by installing the following change:
Change: Q102 from [PN 417-133] to [PN 417-172].
The replacement 417-172 transistor is a 3-lead plastic-case device,
whereas the 417-133 is a 4-lead Metal case transistor so be sure the
transistor leads are installed in the correct holes.
--------------------------------------------------------------------------------------------------------------------
January 14, 1977
SB-313 Bulletin No:
SWL Receiver SB-313-8
Replacement Parts For SBA-310-2 that are NLA
++++Information not available at this time++++
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Thats everything I hold up to 1989 that covers the SB-313. Enjoy!
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Okay Gang - That takes care of the SB-3XX series up to 1989. As stated
before, if I am able to obtain the missing TEB's, I will fill in the
missing ones. Ciao!
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73 de Joe W7LPF/4 [NNN0KUU]
QWCA - SOWP - NCVA - FISTS - RCC
Gordonsville, Va 22942 [Orange Co]
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