Turing Machine mkI in 15V frac power?

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mamonu
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Turing Machine mkI in 15V frac power?

Post by mamonu » Sat Sep 28, 2019 8:09 am

how feasible would be to run a Turing Machine mkI in 15V frac power?

Meaning panel notwithstanding would (perhaps with some modification) the TM work in a frac case? Has anyone done something similar?

I have one euro that is not fitting to my case...and empty space on my frac case 8-)

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emmaker
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Post by emmaker » Sat Sep 28, 2019 4:32 pm

Op-amps won't be an issue here.

The main chips to worry about are the CD4015, CD4016 and the DAC0800. Looking at the data sheets for those show they will work on 15V.

Something to think about to is the LEDs would be a bit brighter. So might want to change R19 to drop the voltage across the LEDs to dim them.

You might want to look at changing R3 or R9 to get the same voltage ratio for the comparator threshold (IC1B, pin 6).

Another trick you could do is put 4 power diodes (something like 1N4001) in series on each of the power rails. That would give a voltage drop of about 2.4V to 2.8V on each rail to get the input voltages to around 12V on the rails. This way you wouldn't have to tweak the circuit. Just make sure you have the diodes going the right way for each rail.

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diophantine
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Post by diophantine » Sat Sep 28, 2019 5:29 pm

There is some discussion in the original build thread. Check this post in particular: viewtopic.php?p=1353927#1353927

TL;DR - it works at 15V. You can probably improve things a bit by changing two resistors. The knob still reacts a bit differently, but it still works fine.

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mamonu
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Post by mamonu » Sun Sep 29, 2019 3:12 pm

Thanks for the info.
Found also another helpful thread that confirms that it can be done.(So it shall be done :bananaguitar: )



Leaving it here for people that have the same idea and want to look for examples.

viewtopic.php?t=127018&postdays=0&postorder=asc&start=0

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