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HP-10 CPU (Fat chance, but…) - [kby] - 02-14-2020 09:26 PM
I'm looking for a source for a working HP-10 CPU chip.
I might also be interested in the battery door (which is the same as the 19c) if there is a not too expensive spare one around. I think I have one but can't seem to find it at the moment. The CPU chip or board is more important.
As the subject says, fat chance, but it never hurts to ask.
RE: HP-10 CPU (Fat chance, but…) - teenix - 02-15-2020 04:04 AM
(02-14-2020 09:26 PM)[kby] Wrote: I'm looking for a source for a working HP-10 CPU chip.
I might also be interested in the battery door (which is the same as the 19c) if there is a not too expensive spare one around. I think I have one but can't seem to find it at the moment. The CPU chip or board is more important.
As the subject says, fat chance, but it never hurts to ask.
There was no chance of getting the microcode out of this model when the HP-10 simulator was put together and I had to write the ROM code myself.
I guess a replacement emulator chip could be made, but again, the code would not be original.
As you say though, never say never :-)
cheers
Tony
RE: HP-10 CPU (Fat chance, but…) - Paul Dale - 02-15-2020 05:02 AM
If I owned a HP-10, I'd be happy for the ROM to be extracted. Even at the cost of the device.
Pauli
And yes, I'm a bit crazy
RE: HP-10 CPU (Fat chance, but…) - [kby] - 02-15-2020 05:26 AM
I'll make a deal with you…
find me a working CPU chip and I'll happliy let you have this one to extract the ROM code from. There's no ROM chip per se so this is the only thing that could contain such microcode; it's more akin to a -65 in that way: one big hybrid chip.
That's not as useless as it sounds. This CPU seems to work fine, except that the pin that handles the entry of the digits "2" and "5" appears disconnected internally in the chip. All functions and printing work OK (printer has some minor issues, but not due to ROM code—just not enough grip on the platen), so I would guess the "ROM code" is perfectly fine, so giving it to the cause of ROM extraction would be a fitting use for what is left.
I don't *know* that that's the problem, but that seems the most likely case given that a similar external disconnect (or bad keyboard) (which doesn't appear to be the case) would cause the same symptom.
If you didn't see it, the discussion is here: HP-10 assembly/disassembly
-kby
RE: HP-10 CPU (Fat chance, but…) - teenix - 02-15-2020 08:31 AM
(02-15-2020 05:26 AM)[kby] Wrote: I'll make a deal with you…
find me a working CPU chip and I'll happliy let you have this one to extract the ROM code from. There's no ROM chip per se so this is the only thing that could contain such microcode; it's more akin to a -65 in that way: one big hybrid chip.
-kby
And that is the problem. The HP-65 hybrid package can be opened easily if need be.
The HP-10 needs something to dissolve the plastic casing to expose the die(s) and the non savvy tech infiltration person might damage the dies as well as him(her)self as well, although I'm sure these things have been done many times past and present. The web seems to suggest boiling the chips in concentrated sulphuric acid.
cheers
Tony
RE: HP-10 CPU (Fat chance, but…) - [kby] - 02-16-2020 03:08 AM
[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 sandwich 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 silicon, but I'd expect the conc sulfuric would damage at least some layers if it ever contacted 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?
RE: HP-10 CPU (Fat chance, but…) - teenix - 02-16-2020 04:45 AM
(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
RE: HP-10 CPU (Fat chance, but…) - [kby] - 02-16-2020 08:45 AM
Attached is a picture that includes the CPU chip. I’d guess the actual die is only under the metal plate. But someone more knowledgeable than I should confirm that.
RE: HP-10 CPU (Fat chance, but…) - teenix - 02-16-2020 10:03 AM
(02-16-2020 08:45 AM)[kby] Wrote: Attached is a picture that includes the CPU chip. I’d guess the actual die is only under the metal plate. But someone more knowledgeable than I should confirm that.
I was sure it was a plastic chip carrier. Oh well, then yes you can gently file down the top of the metal plate and it will eventually peel away leaving the chip(s) visible.
The ROM would be easy to see.
If it is one LSI chip, then reading the ROM might be difficult. I don't know if Peter Monta's method of magnifying the chip to see the HP-35 programming "dimples" on the ROM surface would work here.
My attempt at writing the HP-10 code used about 1.6K of ROM space so the original code should not be overly large.
cheers
Tony
RE: HP-10 CPU (Fat chance, but…) - cruff - 02-16-2020 01:29 PM
I'd expect the metal lid can just be desoldered, exposing the chip(s) underneath.