Output Voltage; In Case Of Difficulty - Heathkit SG-8 Assembly And Operation Manual

receiver is frequently quite critical. For accurate calibration of home built receivers or eq 1ip-
ment,
p? 'ce2d as fcllovs.
Make a rough calibration
with the signal generator. Then,
with a
receiver, tuie in W VV (Bureau of Standards) at 2.5, 5, or 10 mc. Set the signal generator to a
suitable sub-harmoiic, such as 500 or 1000 kc, and adjust the generator for zero beat. Now
hirmonics of the si; nal generator occur every 500 kc or 1 megacycle, and these harmonics may
be used to give acct rate calibrations at points 509 or 1000 kc apart, such as 2500 kc, 3000 kc,
3500 kc, 4000kc, etc. These known frequency points can be marked on the dialof the equipment
being calibrated. Te object of the rough calibration is merely tofurnish a means of identifying
for example, the 3(00 kc point from the 2500 kc or 3500 kc points. For calibration of higher
fequency equipmert, a choice of higher sub-harmonic will reduce the confusion between the
n ultitude of harmo: ics and will also insure adequate signal strength. When checking the cali-
bration accuracy of the Heathkit Signal Generator, the most convenient standards of comparison
of sufficient accuracy are broadcast stations of known frequency. Crystal oscillators of standard
frequency when zerv beat against WWV, are also convenient to use if available. The use of re-
c iver dial calibrations is frequently not of sufficient accuracy to warrant consideration.
Output Voltage: Th2 RF signal strength going into the output control depends upon the strength
of oscillation of the 12A U7 oscillator. In all variable frequency oscillators the amplitude will
vy be minimized.
J MO sesssissass es
Cc
'condenser setting With careful desion th
conaer se ca.retul ae ntr
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with the tu
with unin;
rv
a
MOA DC AUUPlL WaAAA 2, WAL
7
favorable that oscillatio
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ret
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oa ratio of about 2
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becomes suffic iently un
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h when the condense
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may drop off rapid]
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IN CASE OF DIFFICULTY
Recheck the en ire wiring. Follow each lead and color it on the pictorial witha colored
nencil If nossible. have a friend recheck the wiring for vou. Most cases of difficulty re-
praise PY vst, ave BS 20a 2CUMOCUE FAL Wad sai Iv AYU LaDUS Va Mee
sult from wrong or reversed connections. In this unit, there is also the possibility of shorts
to the chaesia neecurringag on some of the har re wire rare) etinnes from the coils.
OY LM UMaooLS YU OUUME EL tip il OUI VE Lal Was wire connections irom tne Cous
should be carefi lly spaced away from the chassis when the instrument i s assemb ed.
y) Check the test load with
rs
ot
n oOhmmatear to he anra thara ara nn aharta ha otwea
ae Ns bit hw es A VAU Wills an WEEREALLLOEO LOL CY BO OUI Oo LEIOL oO ALD Al Olives ts vo
outer conductor caused by overheating during the soldering process.
Q Tf tha wiringisc found tohe correctand the ational canerator atill refuceaty work tery change
We BUC Wiltlipslo LUI LU WO LULL CULL AIIM LIC olpialL Bere, aluyl Otlis LOLUOCS LY ul , ul ULblallp~
ing tubes. It is possible that one of the tubes is defective.
A hank tha unltacad A voltage ehart tea tinalndad ahnwing thea nnymal wunltaga ta ha wrantsaa
"Ee HOUR UIC VULLAE, CO. 4s VULAGRS Ullal 19 LHUULUUCU OLLUWiilf, LEIU fluid ilids VULLARD LY VO EXpecréa
at the pins of the tube sockets. These voltages were measured with an 11 megohm input
vacuum tube voltmeter. A normal variation of +15% is to be expected. With regular volt-
meters, readings may be very much lower. All voltages are DC unless otherwise indicated.
5. If only one band onthe signal generator is inoperetive, it is very likely that the coil associ-
ated with that band hasbecome damaged. Anohn meter connected between the terminals of
he coil should show continuity. if it does not, one section of the winding is open.
WOTTAmh OTanm
VVELAUE UTA
= 1 UBE [pes Pin l Ex Pin 2 2 | Pin 3 SIETIE Pin 4 | Pin 5 ses] pes [pnt [ome [ pe | Pin 6 = Pin 7 = Pin 8 | Pin 9 |
L 6C4 | 65 |_% c [e3ac| 0 | &
|__12Au7 7 8 [F2to-15) 3.5 hassles *75-85 *3to-30/ 0 | 0 |
*Dependent upon frequency.
NC - no connection. aD
Marcus and Levy; Flements of Radio Servicing
Kiver, Milton S.; How to Understand and Use TV Test Instruments
Johnson, < ¢ Richard. How to Use Signal and Sweep Generators