HP-10 CPU (Fat chance, but…)

[teenix]

(02-16-2020 03:08 AM)[kby] Wrote:  [remove HP calculator collector hat[
[put on chemistry PhD hat]

OK, so I sort of hear what you are saying about disassembling the chip, but I'd like to make sure we're talking about the same packaging, then we can talk about how to crack it.

First, I'm curious as to what one actually does to "dump the rom" that requires cracking the case (even in simpler, say, actual ROM cases). I'd always assumed it was a non-invasive process where one just electronically retrieved the contents of the ROM electrically. How does this work if you crack the chip casing?

Conc sulfuric may or may not be the appropriate thing for this. It'll certain chew up the metal pins of any chip (not necessarily the most efficient at it). The chips that are black plasic molded casings, I would think some non-polar organic solvent, or some high-boiling more polar organic solvent might be a better choice. But the HP-10 case doesn't look plastic anyway, it's the kind that looks a purple ceramic sandiwich construction. Are you expecting the conc sulfuric to dissolve the adhesive between the ceramic layers? Not sure how much it will do to the ceramic itself.. BP is 337 ºC; I guess that's low enough not to damage the sllicon, but I'd expect the conc sulfuric would damage at least some layers if it ever contact the inside of the chip. I know I stated it was a hybrid like the -65 but I meant that conceptually (i.e. mutifunctional). Do we know it's actually a hybrid and not just a single multifunctional chip? I guess I can see that cracking the case might at least in theory be useful if it is a hybrid (so could maybe isolate the ROM chip(s)), but if it's a single complicated piece of silicon (like it kinda looks), would that really help?

I've never done it before, so just quoting somewhat blindly from a quick web search.

Bernhard from Panamatik has done ROM dumps, so I guess he would be a good choice for knowledge.

The opened HP-65 hybrid is shown in small attached image.

The HP-10 might be similar but in the different package.

cheers

Tony