Heathkit IT-12 Assembly Manual Download Page 3

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ASSEMBLY AND OPERATION OF THE

HEATHKIT VISUAL-AURAL SIGNAL TRACER

MODEL IT-12

SPECIFICATIONS

Power Supply…………………………………………

Transformer operated

Power Requirements

117 volts AC, 50-60 cps, 25 watts.

Tube Complement

VI  -  12AX7  high  gain  dual  triode,  input  cascade
amplifier.
V2 - 12CA5 beam power output tube.
V3 - 1629 electron beam visual indicator.

Speaker

3 1/2" permanent magnet.

Probe and Test Leads

4' input lead for RF and audio w/switch in probe body.
Two 3' panel test leads with alligator clips.

Dimensions

4 1/2" wide x 7 1/2" high x 4" deep.

Net Weight

4 Ibs.

Summary of Contents for IT-12

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Page 2: ...during the warranty period through no fault of yours we will service it free upon delivery at your expense to the Heath factory Benton Harbor Michigan or to any Heathkit Electronic Center units of Schlumberger Products Corporation or through any of our authorized overseas distributors You will receive free consultation on any problem you might encounter in the assembly or use of your Heathkit prod...

Page 3: ...0 60 cps 25 watts Tube Complement VI 12AX7 high gain dual triode input cascade amplifier V2 12CA5 beam power output tube V3 1629 electron beam visual indicator Speaker 3 1 2 permanent magnet Probe and Test Leads 4 input lead for RF and audio w switch in probe body Two 3 panel test leads with alligator clips Dimensions 4 1 2 wide x 7 1 2 high x 4 deep Net Weight 4 Ibs ...

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Page 5: ...1 and a crystal diode in or out of the circuit for RF or audio applications Condenser C1 isolates the crystal diode to prevent any voltage damage The Noise Switch S3 connects B to the probe lead through resistor R14 to provide the noise locator circuit The switch S2 in the probe must be in the audio position for this function Signals from the probe are coupler through condenser C2 to the gain cont...

Page 6: ...t it is extremely important that particular emphasis be placed on the desirability of following parts placement and wiring dress as shown in the manual This is important in order that the operation of the Signal Tracer be hum free and that a motor boating condition is not induced The wiring dress and parts layout in the manual has been proven thoroughly satisfactory through the construction of a s...

Page 7: ...ase use sleeving Bare wire is used where the lead lengths are short and the possibility of short circuits are non existent ROSIN CORE SOLDER HAS BEEN SUPPLIED WITH THIS KIT THIS TYPE OF SOLDER MUST BE USED FOR ALL SOLDERING IN THIS KIT ALL GUARANTEES ARE VOIDED AND WE WILL NOT REPAIR OR SERVICE EQUIPMENT IN WHICH ACID CORE SOLDER OR PASTE FLUXES HAVE BEEN USED IF ADDITIONAL SOLDER IS NEEDED BE SUR...

Page 8: ...up in a blob on top of the connection with no evidence of flowing out caused by actual wetting of the contact A crystalline or grainy texture on the solder surface caused by movement of the joint before it solidified is another evidence of a cold connection In either event reheat the joint until the solder flows smoothly over the entire junction cooling to a smooth bright appearance Photographs in...

Page 9: ...s Whensolder lugs are mounted under 6 32 nuts the use of lockwashers is unnec essary Don t apply too much solder to the solder joint Don t apply the solder to the iron only expecting that it will roll down to the connection Try to follow the instructions and illustrations as closely as possible Don t bend a lead more than once around a connecting point If it should have to come off due to a mistak...

Page 10: ...der lug as shown in Pictorial 1 In like manner mount binding post F G and H Mount binding post C with a control solder lug under the bushing See Pictorial 1 Mount the speaker switch S4 as shown in Pictorial 1 Use 6 32 screws In like manner mount the noise switch S3 Insert the 3 8 grommet I Connect one lead of a 001 ceramic disc condenser to terminal H NS Connect the other lead to terminal G NS ...

Page 11: ...rdware Connect one end of a 3 length of bare wire to speaker lug 2 Sl Feed the other end thru ground lug B S2 thru terminal lug Cl S2 and wrap around panel ground lug C2 Sl Cut one of the black leads of the output transformer to length strip the end and connect to speaker lug 1 NS Connect one end of a 2 length of hookup wire to terminal lug A Sl Connect the other end to speaker lug 1 S2 This compl...

Page 12: ...t the 2 lug terminal strip at L Mount the 2 lug vertical terminal strip T and at the same time mount the 3 lug terminal strip Q Use 6 32 hardware Mount the 9 pin wafer tube socket VI on the underside of the chassis as shown in Pic torial 3 Use 3 48 hardware Nolockwash ers are used with 3 48 hardware In like manner mount the 7 pin wafer tube socket V2 as shown in Pictorial 3 Use 3 48 hardware Mount...

Page 13: ...Mount the power transformer on the bottom side of the chassis with the wires towards the V2 tube socket Use 8 32 hardware This completes the parts mounting check all parts for correct position and make sure all screws and nuts are tightened securely CHASSIS WIRING Connect the short black wire of the power transformer to lug 3 Sl of the off on switch Sl Twist the two green filament wires of the tra...

Page 14: ...he other end to lug 3 NS of filter condenser C7 Connect one lead of a 330 ohm resistor orange orange brown to lug 3 S2 of C7 Connect the other lead to ground lug U S2 Connect one lead of a 10 K ohm resistor brown black orange to lug 1 NS of C7 Con nect the other lead to lug 2 NS Strip both ends of a 5 length of hookup wire and connect one end to lug 2 NS of C7 Dress the wire towards the front of t...

Page 15: ...ect one lead of a 330 K ohm resistor orange orange yellow to lug 3 NS of terminal strip Q Connect the other lead to lug 2 NS Connect one lead of a 001 mfd ceramic condenser to lug 1 NS of terminal strip Q Connect the other lead to lug 3 NS Connect one lead of a 3 3 megohm resistor orange orange green to lug 1 S2 of terminal strip Q Connect the other lead to pin 7 NS of tube socket V2 Strip both en...

Page 16: ...he spring tube holder on the bracket using the short 6 32 screw and a lockwasher and nut Prepare the 8 pin wafer tube socket by bend ing the lugs as shown with a pair of long nose pliers Connect one end of a 1 meg resistor brown black green to pin 3 Sl Connect the other end to pin 4 NS Prepare the 6 length of 8 wire cable by cutting 3 of the plastic cover off one end and 2 off the other end Pull t...

Page 17: ...ect the lead closest to the marking bands of the crystal diode to lug 1 of switchS2 Sl Caution Crystal diodes can be damaged by excessive heat Use as little heat as possible when soldering Push the other lead of the diode through hole B and twist together with the condenser lead Solder the two leads on the switch side of the board and trim off any excess lead Use an alligator clip to hold wires in...

Page 18: ...the paper backing from the RF AUDIOdecal and place it on the probe body with the audio end towards the tip Assemble the red and black test leads as shown Remove the 3 8 nuts from control Rl and switch Sl Mount the chassis to the panel using a nickel control washer between the panel and the 3 8 control nuts Feed the four remaining wires from the out put transformer through the chassis slot behind s...

Page 19: ...the bottom of the cabinet Install the handle using the two 10 sheet metal screws NOTE The blue and white identification label shows the Model Number and Productions Series Number of your kit Refer to these numbers in any communications with the Heath Company this assures you that you will receive the most complete and up to date information in return Carefully peel away the backing paper from the ...

Page 20: ...nd will require only a few seconds of the technician s time It is suggested however that the user familiarize himself with all phases of the instrument s operation so that maximum benefit can be realized from the investment in the kit The procedures to be followed when using the Signal Tracer are outlined in a general manner only and do not represent the limits of its applications Each individual ...

Page 21: ...he RF probe is not required and the switch in the probe should be switched to the audio position Here again the same general conditions previously described apply to the use of the indicator tube and the speaker From the detector stage pin 5 and 6 of tube C the signal can be traced through the various coupling circuits through the audio and output stage tube C and E and the output transformer Thes...

Page 22: ...maximum position As the test probe is applied to the plate of the IF tube a sharp click will be heard in the signal tracer s speaker A good clean click will indicate proper circuit continuity and operation If there is any frying or crackling sounds present it would be reasonable to assume that some difficulty is being experienced along the circuit and then the test probe should be moved step by st...

Page 23: ...naccessible cabinet location With the Signal Tracer at your disposal it is not necessary to remove the speaker in view of the fact that the output transformer and speaker are available as test or substitution units In the majority of cases the original receiver circuit requirements specify the use of a permanent magnet type speaker and therefore the substitution can be readily made The advantage o...

Page 24: ...nt procedure can quickly be determined by observing the indicator tube The Heathkit Signal Tracer will prove itself an extremely useful and versatile addition to any service shop It is earnestly suggested that the user thoroughly familiarize himself with all phases of its operations so that he may obtain maximum benefit from his investment in this instrument The Heath Company reserves the right to...

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Page 29: ...fically requested by our Consultants Hints Telephone traffic is lightest at midweek please be sure your Manual and notes are on hand when you call Heathkit Electronic Center facilities are also available for telephone or walk in personal assistance REPAIR SERVICE Service facilities are available if they are needed to repair your completed kit Kits that have been modified soldered with paste flux o...

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