HCR ROM/RAM instructions needed

[JonnoW]

Hi,

I have this board but have misplaced my fitting instructions. Can't find any info online.

HCR

Can anyone advise where the 8000, QAmQB,QC,QD and RW connections go? see photo.

Thanks,

Jonathan

[NJ_]

One of those boards was fitted to an early Issue 2 machine when I acquired it. I took a few photos before removing it, so hopefully you can work the connections out from those.

There was quite a lot wrong with the computer itself but it has now been restored to working condition, albeit without the ROM board.

Everything was quite grubby and in rather a poor state, so I have no idea whether it worked in that configuration.

[KenLowe]

Can anyone advise where the 8000, QAmQB,QC,QD and RW connections go? see photo.

The photos provided by NJ_ make sense. My take on this would be:

n8000: S21se - note the jumper between S21sw & S21se should be removed (or attached only to one pin). This will disable the 4 ROM sockets under the keyboard
QA: IC76 (74LS163) Pin 14
QB: IC76 (74LS163) Pin 13
QC: IC76 (74LS163) Pin 12
QD: IC76 (74LS163) Pin 11
RnW: IC72 (74LS245) Pin 1

[JonnoW]

Thanks Ken,

I'll give this a go.


Cheers,

Jonathan.