A small update. We have finished the layout of this board and the staff member who did most of the layout has 'handed it to me' for a seperate check (that way it's MY fault if there is a stuff-up, hahaha).
Here is a close up of the battery backup area showing what we have done here:
Those familiar with these boards will recognise the three large mounting holes for the backup battery. We have included these just as they are on the original board in case anyone is actually stupid enough to want to fit a backup ni-cad........
....…let's face it, the battery leaking is probably the very reason you are building up this replacement board so I can't see many (any?) choosing that option.
Of more interest is the small socket marked "REMOTE BATT" for plugging in a remote battery pack and then to the right of that a small, 2 pin header marked "MEM SW". This takes a standard computer type shorting link and connects the supercap (to the right of the switch) to the 5101 RAM. The reason for the switch is so power can be removed from the RAM in case of repairs or RAM swaps.
So this board provides three backup options:
(1) Exactly as per the original board - ni-cad battery pack mounted on the PCB (stupid idea)
(2) Socket for a remote battery pack (much better idea)
(3) Provision for a Supercap (1F 5.5V) and a link to disconnect the cap when required (also a better idea than the original)
