SL-HF150
Sony 1985
Betamax SL-HF150


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Technical

slhf150 rear view
Rear view

Fault and repair guide

No reel rotation

A common fault with older machines is lack of reel torque. This can result in the machine shutting down in playback or record modes and the tape not being would back into the cassette housing after eject. The best cure for this is to replace the reel chassis. However, because of changes during production you may find that some other bits, such as springs, may need replacing as well. Sony also made available a 'motor mod kit' which consists of a .02mm thick piece of plastic which can be fitted in the worn bearing. Alternatively a small ball bearing can be fitted but this may require the rotor to be filed down to ensure the correct gap between rotor and stator coils.

Audio level controls not operating

Check that the audio monitor is set to Auto. The VU meters only show the Hi-Fi sound level in this mode.

Deck goes into rewind

This can be caused by failure of the tape end sensor. You can check this by unplugging the sensor at its socket on the PCB.
hall effect sensors with glue
Hall effect sensor attached with glue

No head drum rotation

You may find that the head drum fails to rotate. This is due to a problem with the Hall effect device on the head drum motor which is secured by a blob of glue. Full details on how to fix this can be found on the head motor page.

Broken gear (left)


Gear assembly

Failure to load a tape

The cassette carriage can fail to operate. This is caused by breakage of the plastic gears in the side of the mechanism. Often one of the teeth is missing.

When this happens the faulty gears must be replaced and the mechanism correctly realigned so that the left and right side "tray arms" are at the same position relative to the front panel. This is done by releasing the plastic tab on the gear away from the motor side and selecting the correct mesh position with the teeth of the drive cog on rod which connects between both sides of the cassette tray.

This problem is also found on the SL-F30, SL-F60 and the SL-HF77.


Loading gear location

Loading gear and shaft repair

The loading shaft for the Sony has no official replacement but most times it can be repaired, unless the gear is in two pieces or a tooth has broken off. There are two approaches to solve this, either repair the broken gear, or purchase a similar gear and adapt it to fit.
  • Replacement part approach
  • White plastic gears (for RC toy cars) are available quite cheaply on eBay that have 10 teeth, a 2.5mm hole and 5.7mm in diameter and 4.7mm in length.

    In practice the diameter is sufficient and the reduced length does not really matter, just use super glue (or other suitable glue) to glue them to the shaft and protrude the shaft 1mm or so past the end. See: RC-Toy-Car gears

    If you don't need 50 then look for a smaller quantity but the price does not seem to change much.

  • Repair of the existing gear
  • Here is how to repair the shaft when it is out of the machine:
    • Remove the black plastic gear from the shaft and then clean the shaft of all plastic residue.
    • Take the gear and pass a hobby knife (or similar narrow blade) down through the gear crack to remove any plastic residue to allow it to close to its correct gap width.
    • Place the gear in a soft jaw vice such that you can apply pressure to close up the gear crack.
    • Now use a drill with the same diameter as the outside diameter of metal drive shafts knurled shaft end to clean out the rough plastic residue from the shaft hole.
    • Take the gear out of the vice. Take the shaft and put super-glue on it and press the shaft back into the gear.
    • Put the assembly back into the vice again (with the shaft facing down flat, gear top facing up) closing up the gap again but leaving about 3mm of the gear exposed above the top of the vice. (note the gap is facing across the vice gap).
    • Drill a hole the diameter of paper-clip metal through the top of the gear and shaft but just below the surface of the top disc.
    • Insert the wire from an unfolded paper clip and turn both ends hard up, then trim off the excess metal. This will lock the plastic gear to the shaft and should keep tension across the gear and not encourage the gap to open up again.
    • Remove any excess super glue from the cracked tooth gap. The repaired gear may make a slight noise in operation but that is only an issue when loading and unloading. It puts the machine back into normal operation versus a scrap heap or spares. The pin clears the drive gear by a good margin and prevents the plastic spinning on the shaft again.

      Thanks go to Noel Higgins for this fix


Quick fault guide

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