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"That's not a knife."
Dave's in like Flynn. Winner Winner, chicken dinner!
There are much less destructive ways to open an HP 48 and leave it still quite usable.
(05-22-2017 05:51 PM)Han Wrote: [ -> ]There are much less destructive ways to open an HP 48 and leave it still quite usable.

Unless Dave is trying to repair something, he doesn't take a lot of pains to keep the disassembly reversible. The 48 he took apart was one he was sent in a non-working state, as he couldn't bear to open up the previous one he received which was in nice shape.
The other oddity about that calculator was the jumper between ROM and RAM chip. The calculator presumably got upgraded to 128KB, but such an upgrade never required anything more than a RAM chip replacement.
(05-23-2017 01:52 AM)Han Wrote: [ -> ]The other oddity about that calculator was the jumper between ROM and RAM chip. The calculator presumably got upgraded to 128KB, but such an upgrade never required anything more than a RAM chip replacement.

That jumper is on one of the address lines which would suggest a broken land on the board probably from removal of the original chip, but I think a shorter wire could have been used.

Paul.
The labelling on the ROM is unlike any I've seen.

TomC
(05-23-2017 01:52 AM)Han Wrote: [ -> ]The other oddity about that calculator was the jumper between ROM and RAM chip. The calculator presumably got upgraded to 128KB, but such an upgrade never required anything more than a RAM chip replacement.

In the video he said that the original owner damaged a pad when doing the upgrade, so that's probably why there's a jumper wire. I also got the impression that the upgrader didn't know what he was doing 20 years ago when he did the upgrade, which is why it looks like a complete mess during the teardown (just look at the faceplate).
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