VCR G-type drive mechanism adjustments, disassembly and assembly, position of gear wheels and levers, how to eject manually and more...
Drive Mechanism
The
tape deck is fitted with three motors providing:
– Precision drive for the headwheel
– Direct drive for the capstan and the reels
– Drive for the cassette compartment and tape threading/unthreading operations.
Special features are:
– Quick start
– Short winding time
– Automatic cleaning of video heads with a cleaning roller.
To obtain a high repair standard developed a range of service kits (A, B, C …). These kits cover all important spare parts which engage with each other.
The position numbers (Pos. …) in this description are also specified in the exploded views.
Test Equipment / Jigs
– Direct drive for the capstan and the reels
– Drive for the cassette compartment and tape threading/unthreading operations.
Special features are:
– Quick start
– Short winding time
– Automatic cleaning of video heads with a cleaning roller.
To obtain a high repair standard developed a range of service kits (A, B, C …). These kits cover all important spare parts which engage with each other.
The position numbers (Pos. …) in this description are also specified in the exploded views.
Test Equipment / Jigs
Test
cassette
Test cassette (HiFi) Nylon gloves |
9.27540-1011
9.27540-1016 commonly available |
–
cassette compartment
– scanner
– capstan motor
– A/C (combi) head
– scanner
– capstan motor
– A/C (combi) head
When changing the
position of the cassette compartment (lift) during repairs, the compartment
must be moved manually to the "Eject" position on completion of the
repairs
Lowering
the Cassette Compartment by Hand (without cass.)
– Disconnect the video recorder from the mains.
– Release the locks R and S of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the threading motor counterclockwise (Fig. 3) until the cassette compartment is down.
– Disconnect the video recorder from the mains.
– Release the locks R and S of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the threading motor counterclockwise (Fig. 3) until the cassette compartment is down.
Click on the pictures to zoom in
Manual Ejection of the Cassette
If the tape deck does not unthread and eject the cassette by pressing the Eject button this function can also be effected manually by turning the driving gear at the threading motor. To avoid slackening of the tape, turn the capstan motor (counterclockwise) and the driving gear alternately until the tape is completely wound up in the cassette.
If the tape deck does not unthread and eject the cassette by pressing the Eject button this function can also be effected manually by turning the driving gear at the threading motor. To avoid slackening of the tape, turn the capstan motor (counterclockwise) and the driving gear alternately until the tape is completely wound up in the cassette.
Position of Gearwheels and Levers
(deck position "unthreaded, cassette compartment down")
The following diagrams show in detail the marked components and their correctly aligned position on the top and bottom side.
(deck position "unthreaded, cassette compartment down")
The following diagrams show in detail the marked components and their correctly aligned position on the top and bottom side.
Removal and Reassembly of the Cassette Compartment
Removal:
– Disconnect the video recorder from the mains.
– Release the locks R and S of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the driving gear of the threading motor in the "threading" direction until the gearwheel (Pos. 103L) disengages.
– Release the bracket (Pos. 102L) from the shaft of gearwheel "A"
–
Unscrew the 4 screws A on the underside of the cassette compartment.Removal:
– Disconnect the video recorder from the mains.
– Release the locks R and S of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the driving gear of the threading motor in the "threading" direction until the gearwheel (Pos. 103L) disengages.
– Release the bracket (Pos. 102L) from the shaft of gearwheel "A"
– Remove the front panel and raise the cassette compartment to remove it.
Preparations for Refitting the Cassette Compartment:
The cassette compartment and the tape deck must be fitted in a definite position. If the positions of the gearwheels and levers they take after removal have been changed while servicing certain preparations are required before refitting the cassette compartment and the tape deck.
Preparations for Refitting the Cassette Compartment:
The cassette compartment and the tape deck must be fitted in a definite position. If the positions of the gearwheels and levers they take after removal have been changed while servicing certain preparations are required before refitting the cassette compartment and the tape deck.
Gearwheel Positions for Refitting the Cassette Compartment:
– Cassette compartment down, gearwheel "A" engaged.
Note: For video recorders which are fitted with cassette lift gear wheels (A and B) marked with arrows, the arrows must show towards each other.
– Cassette loading gearwheel (Pos. 103L) is released (if it is not the drive gear of the threading motor must be turned to release it).
– Put on the cassette compartment.
– Fasten the cassette compartment with the 4 screws A at the bottom.
– Place the bracket (Pos. 102L) onto the shaft of gearwheel "A" and lock it in.
– Cassette compartment down, gearwheel "A" engaged.
Note: For video recorders which are fitted with cassette lift gear wheels (A and B) marked with arrows, the arrows must show towards each other.
– Cassette loading gearwheel (Pos. 103L) is released (if it is not the drive gear of the threading motor must be turned to release it).
– Put on the cassette compartment.
– Fasten the cassette compartment with the 4 screws A at the bottom.
– Place the bracket (Pos. 102L) onto the shaft of gearwheel "A" and lock it in.
Bottom of Drive Mechanism
Capstan belt (Pos. 126), pulley (Pos. 128G) and sensor print assembly removed.
Capstan belt (Pos. 126), pulley (Pos. 128G) and sensor print assembly removed.
Headwheel
Do
not touch the headwheel with bare hands. Wear the nylon gloves.
Removal:
– Undo 2 screws X, remove the bracket (Pos. 22M) and the head amplifier.
– Insert the reference pin "C" (delivered with each service headwheel) into the hole of the scanner motor and turn the headwheel until the pin locks into the hole of the rotor..
– Set the extractor to the position "3 upper plate" (upper clamping element).
– Insert the extractor into the headwheel.
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the upper clamping element..
– Turn the lever by 90° in the direction of the arrow "CLOSE" and tighten the upper clamping element.
– Change the extractor to the position "0 lower plate" (lower clamping element).
– Insert the extractor into the headwheel.).
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the headwheel together with the lower clamping element.
Removal:
– Undo 2 screws X, remove the bracket (Pos. 22M) and the head amplifier.
– Insert the reference pin "C" (delivered with each service headwheel) into the hole of the scanner motor and turn the headwheel until the pin locks into the hole of the rotor..
– Set the extractor to the position "3 upper plate" (upper clamping element).
– Insert the extractor into the headwheel.
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the upper clamping element..
– Turn the lever by 90° in the direction of the arrow "CLOSE" and tighten the upper clamping element.
– Change the extractor to the position "0 lower plate" (lower clamping element).
– Insert the extractor into the headwheel.).
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the headwheel together with the lower clamping element.
Installation:
– Before fitting the new headwheel, make sure that the motor spindle is clean and undamaged (the spindle should be free of grease and must not be touched with bare hands).
– Put the 3 pins of the extractor into the new headwheel (with protective cap) so that they are inserted into the lower clamping element (the extractor is set to the position "0 lower plate")
– Turn the lever by 90° in the direction of the arrow "OPEN".
– Position the headwheel so that pin "D" of the protecting cap engages with the hole of the stator. Press the headwheel down in the middle with a force of 1N and turn the lever of the extractor counter clockwise in the direction of the arrow "CLOSE".
Attention: The upper protecting cap and the 2 Mylar films (0.15mm thick) remain on the headwheel during this process.
– Change the position of the extractor to "3 upper plate" (upper clamping element).
– Place the clamping element onto the pins of the extractor and turn the lever by 90° in the direction of the arrow "OPEN".
– Position the extractor with the clamping element on the headwheel and turn the lever in the direction of the arrow "CLOSE".
– Remove the protecting cap from the headwheel and withdraw the 2 Mylar films laterally from the air gap.
– Remove the reference pin "C" from the bottom side of the Drive Mechanism.
– Before fitting the new headwheel, make sure that the motor spindle is clean and undamaged (the spindle should be free of grease and must not be touched with bare hands).
– Put the 3 pins of the extractor into the new headwheel (with protective cap) so that they are inserted into the lower clamping element (the extractor is set to the position "0 lower plate")
– Turn the lever by 90° in the direction of the arrow "OPEN".
– Position the headwheel so that pin "D" of the protecting cap engages with the hole of the stator. Press the headwheel down in the middle with a force of 1N and turn the lever of the extractor counter clockwise in the direction of the arrow "CLOSE".
Attention: The upper protecting cap and the 2 Mylar films (0.15mm thick) remain on the headwheel during this process.
– Change the position of the extractor to "3 upper plate" (upper clamping element).
– Place the clamping element onto the pins of the extractor and turn the lever by 90° in the direction of the arrow "OPEN".
– Position the extractor with the clamping element on the headwheel and turn the lever in the direction of the arrow "CLOSE".
– Remove the protecting cap from the headwheel and withdraw the 2 Mylar films laterally from the air gap.
– Remove the reference pin "C" from the bottom side of the Drive Mechanism.
Mechanism exploded view
Adjustment of the Azimuth Angle and Height of the Head
– Connect an oscilloscope to the Audio output.
– Play the section of the test cassette with the 400Hz standard audio signal.
– Adjust for maximum output voltage with the height adjustment screw .
– Play the section of the test cassette with the 8kHz standard audio signal.
– Adjust to maximum output voltage with the azimuth adjustment screw..
– If necessary, repeat this process.
– Check the tilt angle.
If the tape transport was completely out of adjustment or if several components in the tape path have been replaced, it is possible that the have to be repeated several times.
– Connect an oscilloscope to the Audio output.
– Play the section of the test cassette with the 400Hz standard audio signal.
– Adjust for maximum output voltage with the height adjustment screw .
– Play the section of the test cassette with the 8kHz standard audio signal.
– Adjust to maximum output voltage with the azimuth adjustment screw..
– If necessary, repeat this process.
– Check the tilt angle.
If the tape transport was completely out of adjustment or if several components in the tape path have been replaced, it is possible that the have to be repeated several times.
Adjustment of the Horizontal Distance (x-distance)
– Call up the service test programme: Press the "STOP" button on the remote control and then the "play" button on the video recorder and hold them down for at least 5s. Autotracking is switched off.
– Before this adjustment, take out and reload the test cassette (start from Eject position).
– Play back the black/white part of the test cassette.
– With the eccentric screw adjust the "TRIV" signal to maximum voltage (DC-coupling).
– To cancel the service test program: Mains reset or press the "Standby" button.
– Call up the service test programme: Press the "STOP" button on the remote control and then the "play" button on the video recorder and hold them down for at least 5s. Autotracking is switched off.
– Before this adjustment, take out and reload the test cassette (start from Eject position).
– Play back the black/white part of the test cassette.
– With the eccentric screw adjust the "TRIV" signal to maximum voltage (DC-coupling).
– To cancel the service test program: Mains reset or press the "Standby" button.
Brake Band Adjustment
– Lower the cassette compartment. Turn the pulley of the threading motor in the "threading" direction until the cam wheel takes the position shown in Fig. 29.
– Adjust the brake band (Fig. 27, Pos. 14P) by means of the tape tension adjusting tool (from the underside of the tape deck, Fig. 26) so that the edge of the elbow of the tape tension arm (Pos. 15) overlaps with the left inner edge of the left guide.
– Lower the cassette compartment. Turn the pulley of the threading motor in the "threading" direction until the cam wheel takes the position shown in Fig. 29.
– Adjust the brake band (Fig. 27, Pos. 14P) by means of the tape tension adjusting tool (from the underside of the tape deck, Fig. 26) so that the edge of the elbow of the tape tension arm (Pos. 15) overlaps with the left inner edge of the left guide.
Tape Tension Adjustment
– Play a cassette (E 180) starting from the beginning of the tape.
– Measure the tape tension between the full-track erase head (Fig. 22, Pos. 16) and the reverse roller (Fig. 22, Pos. 23) by means of the tentelometer (for this press the full-track erase head to the left).
– Adjust the spring (Fig. 27, pos.11) to a tape tension of 0.24N ±0.02N (24g ±2g) by means of the tape tension adjustment tool.
– Play a cassette (E 180) starting from the beginning of the tape.
– Measure the tape tension between the full-track erase head (Fig. 22, Pos. 16) and the reverse roller (Fig. 22, Pos. 23) by means of the tentelometer (for this press the full-track erase head to the left).
– Adjust the spring (Fig. 27, pos.11) to a tape tension of 0.24N ±0.02N (24g ±2g) by means of the tape tension adjustment tool.
– Lower the cassette compartment. Turn the pulley of the threading
motor (Fig. 3) in the "threading" direction until the cam wheel takes
the position shown in Fig. 29.
– Place the torque meter on the right reel (Fig. 28).
– Turn the capstan motor to move the right reel clockwise.
– Keep turning until the reading on the torque meter does not change any more (Fig. 28).
– The torquemeter must read 10.5 mNm ±25% (105gf-cm ±25%).
– Place the torque meter on the right reel (Fig. 28).
– Turn the capstan motor to move the right reel clockwise.
– Keep turning until the reading on the torque meter does not change any more (Fig. 28).
– The torquemeter must read 10.5 mNm ±25% (105gf-cm ±25%).
Checking the Reverse Brake
– Lower the cassette compartment. Turn the pulley of the threading motor in the "threading" direction until the cam wheel takes the position shown in Fig. 30.
– Turn the lever (Fig. 31, Pos. 19J) to the left so that the swivelling gear (Pos. 17J) does not engage with the right gearwheel (Pos. 18J).
– Place the torque meter on the right reel and turn the latter counterclockwise until the reel just starts to slip (Fig. 28).
– The torquemeter must read 7mNm ±3mNm (70gf-cm ±30gf-cm).
– Lower the cassette compartment. Turn the pulley of the threading motor in the "threading" direction until the cam wheel takes the position shown in Fig. 30.
– Turn the lever (Fig. 31, Pos. 19J) to the left so that the swivelling gear (Pos. 17J) does not engage with the right gearwheel (Pos. 18J).
– Place the torque meter on the right reel and turn the latter counterclockwise until the reel just starts to slip (Fig. 28).
– The torquemeter must read 7mNm ±3mNm (70gf-cm ±30gf-cm).
Pressure Roller (Pos. 37)
– Set the tape deck to the "Eject" position.
– Unhook and remove the pressure roller spring..
– Release the pressure roller guide (pos. 41N) from the guide in the threading motor holder (Pos. 40) and turn the pressure roller guide assembly clockwise until the pressure roller and the guide (41N) can be released and removed..
Attention: Take care that the capstan does not come into contact with grease. Reassemble in reverse order.
– Set the tape deck to the "Eject" position.
– Unhook and remove the pressure roller spring..
– Release the pressure roller guide (pos. 41N) from the guide in the threading motor holder (Pos. 40) and turn the pressure roller guide assembly clockwise until the pressure roller and the guide (41N) can be released and removed..
Attention: Take care that the capstan does not come into contact with grease. Reassemble in reverse order.
Threading Roller Unit, Right
– Set the tape deck to the "Eject" position.
– Compress the two snap hooks by means of tweezers and remove the reverse roller from the holding plate.
– Release the loading arm from the holding plate and push the latter towards the front of the deck to remove it from the guide.
After replacing the threading roller unit (right), check and if necessary readjust the tape transport.
– Set the tape deck to the "Eject" position.
– Compress the two snap hooks by means of tweezers and remove the reverse roller from the holding plate.
– Release the loading arm from the holding plate and push the latter towards the front of the deck to remove it from the guide.
After replacing the threading roller unit (right), check and if necessary readjust the tape transport.
Threading Roller Unit, Left
– Set the tape deck to the "Eject" position.
– Unhook the tension arm spring (pos. 11) to avoid the tension arm spring being pre-loaded.
– At the bottom side of the tape deck, partially unhinge the sensor print and remove the tension lever (pos.112N).
– Compress the two snap hooks by means of tweezers and remove the reverse roller "A" from the plate "B" .
– Release the loading arm (left) from the holding plate and withdraw the latter through the cutout in the chassis.
– Reassemble in reverse order.
After replacing the threading roller unit (left) check and if necessary readjust the tape transport.
See the previous post to know more.
– Set the tape deck to the "Eject" position.
– Unhook the tension arm spring (pos. 11) to avoid the tension arm spring being pre-loaded.
– At the bottom side of the tape deck, partially unhinge the sensor print and remove the tension lever (pos.112N).
– Compress the two snap hooks by means of tweezers and remove the reverse roller "A" from the plate "B" .
– Release the loading arm (left) from the holding plate and withdraw the latter through the cutout in the chassis.
– Reassemble in reverse order.
After replacing the threading roller unit (left) check and if necessary readjust the tape transport.
