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CASIO fx-3600P scientific calculator from 1985
05-29-2018, 12:15 PM
Post: #15
RE: CASIO fx-3600P scientific calculator from 1985
It is possible to overclock these Casio calculator series, but results are not guaranteed.
I didn't try on this particular model, but similar models responds well to overclocking, despite consuming more battery current.

These SoC (system on a Chip) calculators have the oscillator embedded in the chip but usually the operating frequency is set by a single external resistor of usually high value (in the order dozens to hundreds of kilo-ohms).
So, no capacitors, inductors or resonators/crystals are used here to set the oscillator frequency, unlike seen on some other Casio models.

In this model in particular there are only two components to change and test:
- The 220KOhm resistor (most probable component controlling the oscillator frequency);
- The unmarked SMD capacitor (not probable at all, but who knows, testing is required).
Pictures showing these components are available at my first post.

To do this modification, a basic oscilloscope and a current meter in the micro-amp range would be the minimum tools to start changing the oscillator frequency.
A frequency meter of some sort would be useful too.
Changing the components in the blind is not recommended, as the results can be unstable (due to excessive oscillator waveform distortion), or else it will consume excessive current depleting the batteries at a fast rate.

Concerning large capacitance capacitors often seen inside calculators, like electrolytic and tantalum types that also are typically big in physical terms when compared to the other components around), these are used as by-pass/filtering for power supply filtering purposes.

Jose Mesquita member

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RE: CASIO fx-3600P scientific calculator from 1985 - jebem - 05-29-2018 12:15 PM

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