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LED part for Woodstock machines
11-26-2015, 11:54 PM
Post: #7
RE: LED part for Woodstock machines
(11-26-2015 11:38 AM)ElectroDuende Wrote:  I took a bried look to this after our conversation (consdering that it took me several months to restore a couple of calculators, and that my arduinos are in "deep storage" since a long time ago, it was all I could do) Where do you guys buy free time for all this things???

The two problems I see here are:

- The one you noted about spice using independent lines both for annode and cathode of sign indicator, and led moludles having them "shared".
- The fact that spice has both decimal radix and comma. I suppose the way to solve this is connecting the "dot" of led modules to the "comma" and setting the machine to use comma as a decimal radix (done cutting a jumper in the power board) As the comma only ligths when separating decimals, and the dot ligths both on decimals and thousands.

I'll patiently wait for skilled guys like you to solve the problem, and then buy a replacement from you. ;-)

By the way, I removed the clear plastic magnifier over my spice LED module... WOW! Looking at those tiny led modules connected by almost imposible to see gold wires is amazing!
There is some green corrosion on the tracks but I face a dilemma... if I try to clean it, I can break the wires (only half digit is currently failing). If I don't clean, it may end ruining more segments...

I think it is possible to make a replacement for spice LED display when you add some logic gates to the board. The decimal segment can be driven only if decimal and not comma is output. The minus sign must be multiplexed together with other segments. I think there can be used a CPLD or GAL that can do this job. But the smaller size of the QDSP modules gives a worse proportion for spice models, because spice digits are even bigger than woodstocks.

The question will be, is there a demand for a spice replacement LED display? If there is i will make the display when i have time.

I dont think that the green corrosion will get worse when the calculator is stored in normal dry condition.


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RE: LED part for Woodstock machines - PANAMATIK - 11-26-2015 11:54 PM

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