Thursday, October 09, 2008

Fix for 332 earpiece quite problem

An old GPO engineers maintenance trick for fixing the problem of the earpiece being quite on an early Bakelite 332 telephone is as follows:

1) Unscrew the bakelite earpiece (anticlockwise)

2) Slide the metal diaphragm (thin metal disk) sideways off the earpiece magnets (make a note of which way round it is)

3) Make sure the two screws either side of the magnet are tight.

4) Spray the metal diaphragm (both sides) with a small amount of WD40 and wipe off with a piece of paper kitchen towel.
5) Replace the metal diaphragm (the opposite side up to the way it was removed) by sliding it sideways back onto the magnetic coils.
6) Screw the bakelite earpiece back on.

Then try the telephone again and see if this improves the sound (works about 50% of the time).

Sunday, July 20, 2008

Safely Removing a Bakelite Mouthpiece

To safely remove the mouthpiece from a British Bakelite telephone handset (Type 164) used on both 200 series and 300 series bakelite telephones, follow the following instructions.

1) Carefully insert a fine pointed instrument such as a compass point or probe from a multimeter (as shown below) into the release hole of the bakelite mouthpiece. Be very careful not to damage the bakelite.

2) Applying gentle pressure to the release spring inside the mouthpiece rotate the bakelite mouthpiece anticlockwise by 1/2 an inch (as shown below).

3) At this point the bakelite mouthpiece should just lift clear of the main telephone handset.

4) The carbon granule microphone is now exposed.

5) Replacement of the mouthpiece is simple, just put the bakelite mouthpiece on and rotate it 1/2 clockwise (if adjusted correctly it will lock onto the telephone handset).

Fix for a Slow dial on 746 Telephones and 706 Telephones

Vintage 746 telephone and 706 telephone dials are lovely mechanical devices (similar in many ways to antique clocks) however because they ar...