Casella CEL CEL-393 - Manual (Page 64)

The kit comprises a circuit panel, two insulating pieces, and a new
programme ROM. Fitting should be undertaken only by a competent
electronics technician who is experienced with handling delicate elec-
tronic equipment.
1. Prior to fitting the circuit panel, check that the instrument is
operating correctly as an A version.
2. Remove the battery and lift the rear cover.
The diagram in Figure 9 shows how the panel and insulators
should be placed inside the instrument.
3. Take care to ensure that the pin connectors to the two panels
are correctly aligned prior to pushing them together.
/60. 393 Handbook