Sams 70-7 - Early Television Foundation

20 .Q1MFD21 .01MFD1920 .01MFD2324 .01MFD26 200MMFDRADIO ALIGNMENT INSTRUCTIONSALIGNMENT INSTRUCTIONS— READ CAREFULLY BEFORE ATTEMPTING ALIGNMENTWhen complete receiver alignment Is to be performed align the FM IF Amp. before aligning AM IF Amps.To set pointer turn tuning cap fully closed and set pointer to last reference mark at low frequency end of dial.Volume control should be at maximum position.obtain an output reading.Output of signal generator should be no higher than necessary toUse an Insulated alignment screwdriver for adjusting.FM IF ALIGNMENT USING AM SIGNAL GENERATOR AND VTVMConnect two matched 100K2 (t 1%) resistors In series from Polntdj^to chassis.Is alignment Pointas shown on the schematic.SIGNALSIGNAL BANDDUMMYGENERATOR GENERATOR SWITCHANTENNACOUPLINGFREQUENCY POS.19 .01MFD High side to pin 1 10.7MC FM(Grid) Of 6AU6 (V23). (Unmod. ) (Ext.Low side to chassis.clockwise.).01MFDAcross antenna terminals.10.7M3RADIODIALSETTINGTuning gangfully closediiCONNECTVTVMDO Probe toPolnt Commonto Pointf>DC Probe toPoint^ Commonto chassis.•Use frequency modulated signal with 60^, modulation and 450KO sweep.horizontal deflection.SIGNALCONNECTDUMMYGENERATORANTENNASCOPECOUPLINGAcross antenna terminals.DUMMYSIGNALANTENNAGENERATORCOUPLING22 Two 1202Across antenna terminalswith 120Scarbonres. resistor in eachlead.SIGNALGENERATORFREQUENCY10.7MC(450KCSweep )SIGNALGENERATORFREQUENCY106MC90MCBANDSWITCHPOS.FMBANDSWITCHPOS.FMRADIODIALSETTINGTuning gangfully closed;M RF ALIGNMEURADIODIALSETTING106MC(5 3/4" toright ofleft handcalibrationmark at lowfreq. end ofdial backplate).9 CMC(1 1/8" toright ofthereferencepoint listedabove) .Vert. Amp. toPoint\/>. Lowside to chassis.Vert. AmP- toPoint^p Lowside to chassis.CONNECTVTVMDC Probe toPoint ^pi Commonto chassis.ADJUSTA36A37A38,A39,A40,A41The Junction of these two resistors'REMARKSAdjust for maximum deflection.Adjust for zero reading. A positiveand negative reading will beobtained on either side of thecorrect setting. Repeat steps 19and 20 If A37 required much adjustment.Adjust for maximum deflection.Alternately load the primary andsecondary windings of the IFtransformers with 680ffl while theopposite side of the same transformeris being adjusted.Use 120% sawtooth voltage In scope forADJUSTA36,ASS,A39,A40,A41A37ADJUSTA42,A43A44,A45REMARKSDisconnect stabilizer C7. Adjustfor maximum amplitude and symmetryas per Fig 5.Reconnect stabilizer cap C7. AdjustA37 so crossover point occurs atcenter of pattern as per Fig 6.Slightly retouch A36 for maximumamplitude and stralghtness ofcrossover lines. Continue withstep 22.REMARKSAdjust for maximum deflection.25 200MMFD High side to terminal2 of antenna terminalstrip. Low side tochassis.1400KC600KCFM IF alignment must be complete before starting AM alignment.Volume control should be at majcimum position. Output of signal generator should be no higher than necessary toobtain an output reading. Use an insulated alignment screwdriver for adjusting.DUMMYSIGNALSIGNAL BAND RADIOANTENNAGENERATOR GENERATOR SWITCH DIALOUTPUTCOUPLINGFREQUENCY POS. SETTINGMETERADJUSTREMARKSHigh side to pin 7 4S5KC AM Tuning gang Across voice A46,(Grid) of 6BE6 (V21). (40CA, (3 pos-fully closed coilA47,Low side to chassis. Mod.)A48,A49itionsclockwise)1400KC(5 15/16" tothe right ofleft handcalibrationmark at lowfreq. end ofdial backplate).600KO(1 1/4" tothe right ofthereferencepoint listedabove.A50,A51A52,ASSiiAdjust for maximum output. Alternatelyload the primary and secondarywindings of the AM IF transformerswith 47KS2 while the oppositeside of the same transformeris being aligned.Adjust for maximum output.Adjust for maximum output. Repeatsteps 24 and 25.FIG.5 FIG. 6PAGE 8