I DO NOT SUPPLY
The HMV Exhibition
This page deals with the refurbishement of a brass Exhibition soundbox I obtained at auction for my HMV No. 6 gramophone. In this instance it was only necessary to replace the gaskets but occasionally the back insulator will need replacing. Although hardened, I considered mine in good enough condition not to warrant replacement. As much information on the refurb can be gleaned from the No. 4 information I have simply dealt with points to look out for. Together with the photographs in the panel, these should provide sufficient of a guide. One blessing is that unlike the later No. 4's and 5's soundboxes the whole of the body is brass, so problems encountered with pot metal are not encountered.
1. Remove the 3 screws that connect the back of the sound box. (Should the insulator need replacement try Ken Priestley or Zwarteschijf.nl in left hand panel. NB Gasket tubing is also available from these suppliers)
2. Remove needlebar screw. Take care not to lose the small washer which may be covered in old wax.
3. Remove the gasket, diaphragm and front gasket.
4. Clean parts as required - diaphragm, needlebar, screws, back and needlebar assembly as required. Note. Any lettering that is no longer visible on the back can be reinstated by using an indelible white ink pen. ( I use a Uni Paint white marker.) Go over any missing letters. Allow the paint to go off. Using a piece of fairly coarse fabric ( I use a piece of felt), ensuring the fabric is pulled tight over the end of the finger, rub the excess paint away. This should leave white paint in the engraved letters. (It shouldn't take more than a few seconds for the paint to go off, too short a time and the paint will be removed from the engraving, too long and the excess will be difficult to remove.)
5. Cut two lengths of gasket ensuring nothing short of excellent joints where the edges meet.
6. Insert what will be the front gasket with the join at the bottom, pivot end, of the box.
7. Place the diaphragm in position on the front gasket ensuring no contact with the box sides.
8. Add the other gasket with the join this time at the top.
9. Fit the back but do not tighten the screws. Leave them in a position that just hold the back in place. This will allow for alignment of the diaphragm with the needlebar.
10. Use a scribe or similar fine pointed tool to align the hole in the diaphragm with the needlebar hole. Replace the needlebar screw and washer. ( It may be easiest to remove the insulator to do this to give more clearance).
11. Using beeswax, wax the point where the needlebar fixes to the diaphragm as described in the No. 4 soundbox refurbishment.
12. Tighten the back screws.
The needlebar assembly can be removed by removing screws maked A in bottom left photo of the panel. Further stripping can be carried out to thoroughly clean components. Assembly is the reverse procedure bearing in mind the requirements referred to in the diagram in the bottom right illustration of the panel.