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Old 25th Oct 2018, 8:21 pm   #27
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 2,865
Default Re: Retired Texas TI99/4A engineer needs help please.

And a datasheet for the uA723:

If you want to check the functionality of the uA723 you could always breadboard the basic linear regulator application circuit from page 5 of the datasheet. It just needs the IC and a handful of passive components. (Suggested component values are on page 4).

I'm not suggesting this could be used as a substitute for the original switching regulator design (It can only output 150mA maximum), just to use it as a way of functionally testing the IC before you go buying another one.

If the uA723 IC doesn't even work in that basic linear mode then you can probably say that it is dud.
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