Minolta MC 85mm f1.7 Disassembly Tutorial

Easy disassembly method for lens cleaning (mold removal)

Difficulty ★★★☆☆

 

Things to prepare

  • JIS cross-point precision screwdriver
  • Kitchen rubber gloves
  • Spanner Wrench
  • Blower or compressed air
  • Lens cleaning paper
  • Lens cleaning liquid (lens cleaner)

 

Size comparison with the later compact 85mm f2.

 

Grab the inscribed ring with rubber gloves, remove it counterclockwise, and turn the distance ring to the shortest side.

 

Pull out the filter frame and remove it.

 

Grab the front lens unit with rubber gloves and remove it counterclockwise.

 

Turn the lens over and remove the rear cap.

 

If you remove only 4 long screws from the 8 screws on the lens mount, the lens mount will come off as a unit.

Note! When the aperture ring is lifted, it will come off, but at this time the spring of the click stop will bounce and the tiny bearing will tend to go missing.

 

Remove the rear lens unit counterclockwise with a spanner tool like the one shown in the photo.

 

Clean with lens cleaner and paper. First, don't forget to blow off the dust with a blower!.

The front and rear lens groups sandwiching the aperture are in a "unit structure" housed in a metal tube. The lenses facing the outsides of this unit are hard coated, so it is okay to clean them, but if you disassemble it, the lenses on the inside are soft and scratch easily.

 

 

Cleaning when the diaphragm blades are filled with oil

 

With the front and rear lens units removed, temporarily fix the lens mount unit with screws.

 

Remove the screws marked with red arrows.

 

Pull out the aperture unit upward.

 

Clean the aperture mechanism with a solvent. The red arrowpoints to the aperture cam.

 

The blue arrows point to the infinity adjustment screw of the distance ring.

The red arrow is the keyway of the straight helicoid.

The green arrows point to an automatic aperture interlocking pin and F-number transmission pin holder for open metering.

 

Optical diagram of the MD 85mm f1.7 lens.

 

 

 

 

 

 

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