Does anyone here have Gerber files for something like the FC microbus?
I loved the fc power boards but am working on several separate cases and even at £8 a board I think I need to look at the jlbpcb option.
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I’m getting boards made based on the MFOS Wall Wart Supply. It’s approximately the same as the FC Power but with no 5 V. @juggle adapted the design for home etching and appears to be using it without problems, but I haven’t tested it myself yet.
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Yep, two of them in the new case and I’ve run a few modules off them successfully. (though my first DIY 3340 is dead again for some reason…need to look into that - doesn’t appear to be power supply related.)
Though my design is modified it’s logically the same.
I’m also using 1.35a polyfuses - but haven’t tried to load it up to see if I can trip one yet.
Oh - and instead of the capacitor values specified in @analogoutput’s design I used the values from FC’s assembly instructions (4700uf caps, 1uf’s before the regulators, 100uf’s after) Though on my own schematic I seem to have marked it as 1uf’s and 10uf’s for some reason. And AO just has 1uf in both positions. And honestly in most cases any of them are probably fine.
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I’ve specified the MFOS cap values.
I don’t know enough to judge between the MFOS and FC values, but I will point out the TI LM78xx datasheet shows 0.22 µF on the regulator input and an optional 0.1 µF on the output. ST’s L78 datasheet’s application circuits have 0.33 µF on the regulator input and 0.1 µF on the output. Why FC is using caps a thousand times larger on the outputs I have no idea.
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Because there weren’t any knobs that could be made go to 11 perhaps?
They did call for smaller caps on the input (100nf) in their prior version with no explanation I’ve found for why they made the change…but they went from less than suggested to more than suggested. And were always way more than suggested on the output side.
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I would expect large capacitors at the input of the voltage regulator which the regulator can use to drain current from quickly when needed. If large capacitors follow the regulator, it will have a more difficult job to maintain the output voltage because it is hampered to do so by the large capacitors (which need large currents to be refilled). The dynamic stabilization of the output voltage by the regulator should be better than the capacitors can achieve.
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