HEPAX - from the treasure chest

[KimH]

As a teaser here is the CAT :MASSMEM I did on the 9114B with my 71B.

I will do one BOLD for readability ASAP

CAT - HEPAX Floppies

(09-22-2020 05:41 PM)KimH Wrote:  I could read the floppies - no errors!

My dayjob is getting in the way of moving the files form Floppy to something usable on this site.

I have a plan, but need a couple of hours to make sure I don't ruin the disks while making copies and move files through ILPer to actual postings. This will be over the weekend.

/KimH

(09-21-2020 07:38 PM)SteenPetersen Wrote:  Hi J-F,

it looks like the epoxy was not strong enough ;-)

We did not have a lot of money, so we only created one model of the ceramic substrate. We needed to be able to produce four - actually five - different versions of the module with only one substrate. So we got the small company who assembled the modules to "program" the modules before assembly. This was done by cutting at exactly the right spot before applying something which was very hard to remove - I think it was epoxy, but I am not sure. I think it was a laser doing the cutting, but I do not remember - I was busy coding and did not see where this was actually done.

I did leave you a small clue together with the picture I posted of the breadboard - the instruction for the DIP switch settings - switch #8 controls the 8K/16K setting. As you can see there are no DIP switches on the real module, so here we have to do a permanent cut instead. So basically the hardware was identical for all modules, except no EPROM on the MEM modules. By the way - the fifth version was a ROMONLY device for custom usage (I think without the bank switching - there is a control point for that as well) - unfortunately we never got to sell that.

As far as I remember then the chip was a custom gate array made by Fujitsu (we worked with a local danish company - Nordisk Elektronik - who had the relationship with Fujitsu). The chips were soldered at Bruel & Kjaer, while the connector (which we bought from HP) was soldered by the small company who also made the plastic moulding (as far as I recall, but I may be wrong). Here the final assembly also took place - with all the glue ;-)

Regards,
Steen