Fixing small plastic... things

Tony Duell ard at
Wed Dec 8 13:37:47 CST 2010

> On 2010 Dec 7, at 2:39 AM, Christian Corti wrote:
> > On Mon, 6 Dec 2010, Brent Hilpert wrote:
> >> The EC-130 (and by extension the 1162) is one I have wanted to RE and 
> >> produce a simulation of, both for the vector display and because the 
> >> arithmetic technique used is different than most.
> >
> > Did you already have a look at the Friden patents?
> >  No. 3523282
> >  No. 3526760
> >  No. 3546676
> >  No. 3725873
> No, I haven't. The objective is to make a precise gate-level simulation 
> of the calculator, both for understanding and which can be used to 
> track down faults in a broken instance of the real thing. Patents 
> generally don't provide the level of accuracy for that objective, so it 
> generally doesn't occur to me to look to patents for these purposes.

As n aside, some of the HP desktop calcualtor patents are very detailed, 
and include sechematics, commented firmware source, extension ROM 
sources, and so on. But as you imply, there are often suble differences 
between the machien described i nthe patent and the actual prodcution 
model. I regard these patents as a very useful resource and well worth 
reading, but you need to check against an actual machine.


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