The three glass panels fit into slots in the vertical pillars. Despite the tape you applied in the previous step, there is some risk they may fall out as you release the case from the base. If so, they may crack or get chipped. Replacement glass panels with their bevelled edges might be hard to source.

With the clock on its face and if possible, holding the case to ensure that the vertical pillars hold the glass panels, remove all four screws in the base and remove the base.

Check to see whether any of the glass panels is now loose and at risk of falling out. If so, carefully remove it and put it aside. Put the case aside standing upright, so that at worst, the glass panels can only slip down in their grooves until they are resting on the table.

If any of the glass panels come out you may well find thin plastic strips in the grooves to take up any slack and so that the glass doesn't bear directly on the brass of the pillars. Take care not to lose these strips.

On reassembly, if any of the glass panels and their plastic strips came out, ensure that the strips are at the far ends of the grooves from the base otherwise you may not be able to get all the screws in the base to engage with the threaded holes in the pillars.