Major Component Replacement Procedures

4-1 TAPE TRANSPORT↑ TOP

In order to gain access to the tape transport components, place the recorder in an upright position and remove rear cover, two side panels, and top panel (16 screws total).

Refer to Section 6 for parts lists and exploded views of the transport assembly to aid in the identification of the various components.

4-1-(1) REEL TABLE REPLACEMENT AND HEIGHT ADJUSTMENT↑ TOP

The reel table may be removed by removing three cross head screws accessible from the front of the transport. To adjust the reel table height, loosen two hexagonal socket head screws shown in Fig. 4-1, adjust height and retighten screws.

⤢ zoomFig. 4-1 Reel Table and Motor · Redrawn as vector — zooms cleanly · view the original scan

4-1-(2) SUPPLY OR TAKEUP REEL MOTOR REPLACEMENT↑ TOP

To replace the supply or takeup motor proceed as follows:

1. Loosen two hexagonal socket head screws on the reel shaft holder (Fig. 4-1) and remove reel table and holder.
2. Tag and unsolder motor leads from the attached printed circuit board.
3. Remove four motor mounting M4 nuts.
4. Remove four motor mounting crosshead screws.
5. Install new motor in the reverse order of removal and adjust reel table height.

4-1-(3) POWER TRANSFORMER REPLACEMENT↑ TOP

To replace the power transformer (refer to EXPLODED VIEW 2), proceed as follows:

1. Tag and unsolder all transformer leads from the terminal.
2. Remove four M4 nuts that secures [sic] the transformer to the transport. (Ref. No. 2-18)
3. Install new transformer in the reverse order of removal and resolder leads to the terminal of the transformer.

4-1-(4) CAPSTAN MOTOR REPLACEMENT↑ TOP

On models 2S or 4S (Hysteresis synchronous motor machines).

To place [sic] the capstan motor (Fig. 4-1 and refer to Exploded View 4), proceed as follows:

1. Tag and unsolder all motor leads from the printed circuit board.
2. Remove entire motor assembly and mounting bracket by removing four cross head screws accessible from the rear of the transport.
3. Remove motor pully [sic] from motor shaft by loosening an allen head screw.
4. Remove motor from mounting bracket and replace with new motor.
5. Reinstll [sic] motor assembly and mounting bracket in the reverse order of removal. Adjust bracket position to tighten drive belt before cross head mounting screws are tightened.

⤢ zoomFig. 4-2 Capstar Motor Location (2S or 4S) · Redrawn as vector — zooms cleanly · view the original scan

On models 2SD or 4SD (DC servo controlled motor machines)

The capstan motor should be replaced with servo control printed circuit board assembly, to replace the capstan motor proceed as follows: (Refer to EXPLODED VIEW 4-2)

1. Remove connector on servo control printed circuit board assembly located above capstan.
2. Remove servo control printed circuit board assembly with mounting plate by turning four M3 crosshead screws "B" on mounting plate.
3. Remove capstan dust cap from face of transport. (Ref. No. 4-102)
4. Remove capstan mounting plate with capstan motor by removing four M4 crosshead screws "A" on the mounting plate.
5. Remove the capstan motor by removing three M4 crosshead screws "C" on the mounting plate and install new capstan assembly in the reverse order.

⤢ zoomFig. 4-3 Capstar Motor Location (2SD or 4SD) · Redrawn as vector — zooms cleanly · view the original scan

4-1-(5) BRAKE BAND OR BRAKE SOLENOID REPLACEMENT↑ TOP

When a new brake band or new brake solenoid is installed (Fig. 2-2), it is necessary to position the brake guide and/or brake solenoid to ensure that there is uniform brake band clearance around the brake drum when the solenoid is energized. Also the brake solenoid plunger must bottom in the solenoid housing when the solenoid is energized. When the solenoid is deenergized, the brake band should uniformally [sic] contact the drum surface. After installation, perform the Brake Adjustment procedure given in Section 2 of this manual. After completion of the adjustments place the recorder in play mode for 30 minutes. Then press STOPand [sic] PLAY pushbuttons to ensure that the solenoid bottoms when it is hot.

⤢ zoomFig. 4-4 Brake Assembly Location · Redrawn as vector — zooms cleanly · view the original scan

To replace the brake band or brake solenoid, proceed as follows:

1. Remove brake spring and retaining ring "A".
2. Remove retaining ring "B" of solenoid pin. [sic] and remove solenoid pin.
3. Remove solenoid housing with plunger by removing two hexagonal socket head screws.
4. Install new solenioid [sic] housing with plunger and set solenoid housing so that plunger stroke is 0.2 ± 0.02 inch (5 ± 0.5 mm).
5. Remove spring pin of brake lever and remove brake band by removing two cross head screws.
6. Install new brake band in the reverse order.

4-1-(6) PINCH ROLLER REPLACEMENT↑ TOP

To replace the pinch roller assembly proceed as follows:

⤢ zoomFig. 4-5 Pinch Roller Removal · Redrawn as vector — zooms cleanly · view the original scan

1. Remove pinch roller cap by turning counterclock wise [sic].
2. Install new pinch roller.
3. Reinstall nylon washer and pinch roller cap in the reverse order.

4-2 HEAD ASSEMBLY REPLACEMENT↑ TOP

This section provide [sic] a description of the head assembly, procedures for changing head stacks and adjustment procedures for adjusting head azimuth (tilt), head height, head zenith (perpendicularity) and tape wrap (racking). These adjustments are required whenever a head stack is replaced.

NOTE

AFTER HEAD ALIGNMENT, ALIGNMENT SCREWS (AZIMUTH, ZENITH, HEIGHT) SHOULD BE LOCKED UP WITH ENAMEL PAINT.

DESCRIPTION

The head assembly is mounted on three tape-guide posts and secured in place by three screws labled [sic] "M" in Fig. 4-6.

The insulating shield for the head assembly printed circuit board is secured by screws labled [sic] "S". Each head stack is secured to a bracket by screws labled [sic] "W" with a spacer between the bracket and head stack. Each bracket is suspended from the head base by three spring-loaded screws labled [sic] "H", "A", and "Z". Screws labeled "W" are used to adjust tape wrap. Screws labeled "H", "A", and "Z" are used to adjust height, azimuth, and zenith.

A head stack may be removed and re-lapped (face resurfaced) if the amount of wear is small and only an indication of poor head-to-tape contact is evident. Poor contact is a result of improper adjustment and is evidenced by loss of high frequency response of the record or reproduce head stack, difficulty in achieving bias peak (record stack), or insufficient erase stack erasure.

HEAD STACK REPLACEMENT

To change a head stack, proceed as follows:

1. Lift head cover, remove AC power cord.
2. Remove three screws labeled "M" and pull out the head assembly from head connector.
3. Tag and unsolder (use low wattage pencil type iron to prevent damage) leads at rear terminal of the head stack.
4. Remove head stack by removing two screws labeled "W".
5. Install new head stack and resolder leads.
6. As a preliminary adjustment, measure the distance between the head base and the bracket at a point near spring-loaded screws "A", "Z", and "H". If necessary adjust screws for equal spacing.
7. Lay a piece of ¼-inch tape over the spacers and head stacks as shown in Fig. 4-7. Note if the leading and trailing wrap angle around the head stack is equal. If not equal, correct by loosening screw "W", adjusting head stack, and retightening screws. Remove the three screws and spacers installed in step 7.
8. Remount the head assembly. Perform the appropriate head alignment procedure given below.

Following adjustment are [sic] necessary whenever head is replaced.

1. In case of reproduce head replacement. A. Reproduce Equalization Adjustment (See 3-5-([illegible]) ) B. SRL Calibration (See 3-5-(6) )
2. In case of record head replacement. A. Bias Calibration (See 3-6-(1) ) B. Record Level Calibration (See 3-6-(3) ) C. Record Equalization Adjustment (See 3-6-(4) ) D. SEL/REP Level Adjustment (See 3-6-(5) )
3. In case of erase head replacement A. Bias Calibration (See 3-6-(1) )

RECORD OR REPRODUCE HEAD ADJUSTEMNT[sic]↑ TOP

Follow the procedure for Reproduce Amplifier Alignment given in Section 3 of this manual. For the final adjustment of a record stack, the height and azimuth adjustment may be accomplished in the same manner as for a reproduce head stack by playing back an alignment tape with the recorder in the selective reproduction mode (SEL/REP switches "in"). Use the 10 kHz tone for azimuth adjustment.

ERASE HEAD ALIGNMENT↑ TOP

Erase head azimuth is not critical, however wrap angle and head height relative to the record head is important to achieve maximum efficiency. Poor erasure is often caused by misalignment of the erase head. Before making any attempt to adjust the erase head stack, an entire electronic alignment procedure (reproduce, record, and bias amplifier alignment) should be performed so that the record and reproduce head heights are correct, SRL/CAL setting is correct, and bias and record levels are properly calibrated. If [sic] should be also noted that in some cases, high coercivity tape can be the cause of poor erasure.

An approximate erase head adjustment can be accomplished using headset or a speaker/amplifier. However, for precise alignment, a wave analyzer should be used. Proceed as follows:

1. Follow the procedure for Erasure Test steps 1 through 6 given in Section 3 of this manual.
2. Observe reading on wave analyzer and turn screw "H" (Fig.4-5) ¼ turn clockwise. If the reading decreased, turn screw "A" and "Z" ¼ turn clockwise. If the reading increased when "H" was turned ¼ turn clockwise, turn "H" counterclockwise past the original setting to ¼ turn counterclockwise. If the reading decreased, turn screw "A" and "Z" counterclockwise by the same amount.
3. Repeat step 2 in small increments to achieve a minimum reading on the wave analyzer. Typical amount of erasure should be 65 dB or better. Note: After "H" is turned, be sure to turn "A" and "Z" the same amount.
4. If the adjustment of erase head height alone cannot achieve satisfactory erasure, set screw "H", "A", and "Z" for minimum reading on the wave analyzer. Note that there are two vertical gaps on the face of the erase head. The trailing gap has the most effect on erasure and must be in good contact with the tape. Loosen screws "W" slightly and rotate the erase head stack for a minimum reading on the wave analyzer. Tighten screws "W".

⤢ zoomFig. 4-6 Top View of Head Assembly · Redrawn as vector — zooms cleanly · view the original scan

⤢ zoomFig. 4-7 Front View of Head Assembly · Redrawn as vector — zooms cleanly · view the original scan

⤢ zoomFig. 4-8 Bottom View of Head Assembly · Redrawn as vector — zooms cleanly · view the original scan

⤢ zoomFig. 4-9 Head Alignment · Redrawn as vector — zooms cleanly · view the original scan

4-3 INSTALLATION OF OPTIONAL TRANSFORMER↑ TOP

4-3-(1) INSTRUCTION OF INPUT TRANSFORMER↑ TOP

Follow the instruction to install the input transformer.

⤢ zoomFig. 4-10 Input Circuity · Redrawn as vector — zooms cleanly · view the original scan

Input transformer has terminals as shown above surrounded by broken line.

1. Take out case rear board as shown in Fig. 2-1, and out Rear Panel [sic]. Then mount the transformer with two screws. (See Fig. 4-12)
2. Remove wires from XLR connector. Solder Hot Line (Orange) to transformer output side number 5, Solder Cold Line & Shied [sic] to terminal number 8.
3. Solder Hot Line (Orange) premounted on the transformer to XLR connector number 3, Cold Line (White) to XLR connector number 2, and Shield to XLR connector l [sic]. (See Fig. 4-13)
4. Take out the bottom board and re-wire the PCB as shown below.

⤢ zoomFig. 4-11 P.C. Board Wiring · Redrawn as vector — zooms cleanly · view the original scan

A Take out jumpers 1 and 2 . B UM-solder [sic] 3 and solder to 5. C UM-solder [sic] 4 and solder to 6.

⤢ zoomFig. 4-12 Input Transformer Installation · Redrawn as vector — zooms cleanly · view the original scan

⤢ zoomFig. 4-13 Input Transformer Wiring · Redrawn as vector — zooms cleanly · view the original scan

5. After all of above modification, please test record.

4-3-(2) INSTALLATION OF OUTPUT TRANSFORMER↑ TOP

Fig. 4-15 [sic] shows circuity of unbalanced output and balanced output. To install input transformer [sic], proceed as follows:

⤢ zoomFig. 4-14 Output Circuity · Redrawn as vector — zooms cleanly · view the original scan

Transformer has terminals as shown above surrounded by broken line.

1. Take out case rear board in the Fig. 11-1 [sic], and then take off rear panel. Mount the transtormer [sic] with two screws.
2. Remove wires from XLR connectors. Solder Hot Line (Orange) to transformer terminal 1, and Solder Cold Line (White) and Shield to terminal 2.
3. Solder Orange Wire coming out of terminal 5 to XLR connector number 3, Solder White Wires coming out of terminal 8 to XLR connector number 2, Solder Shield Wire to XLR connector number 1.
4. After above wiring, put test tape and adjust reproduce level.

⤢ zoomFig. 4-15 Output Transformer Installation · Redrawn as vector — zooms cleanly · view the original scan

⤢ zoomFig. 4-16 Output Transformer Wiring · Redrawn as vector — zooms cleanly · view the original scan