Homebrew power supply for Mandax FD3A external floppydrive

[satjanand]

Hi there,

So I've run into a Mandax FD3A external floppydrive by Lischka Datentechnik which wasn't accompanied by its power supply.

Opening the box, showed that only 5V is fed to the NEC FD1037A floppydrive inside. It can't be that difficult to create a power supply for it, can it? I happen to have a variety of spare voltage adapters lying around, so I thought I'd come to this forum for help.

There are two capacitors inside that accompany the LM340T5 voltage regulator, set in fixed output configuration. On the input side, the capacitor is marked "104" and on the output side the capacitor is marked "1016".

I would like to know, if it's as easy as connecting two wires from a voltage adapter to the input and ground. If so, what specs should the adapter have?

Thanks in advance!


Link to LM340T5 spec sheet:
https://people.ece.cornell.edu/land/cou ... M340T5.pdf

Here are some pics:

IMG_20230916_122914.jpg (158.36 KiB) Viewed 1165 times

IMG_20230916_122742.jpg (199.86 KiB) Viewed 1165 times

IMG_20230916_122714.jpg (219.25 KiB) Viewed 1165 times

IMG_20230916_122734.jpg (271.56 KiB) Viewed 1165 times

IMG_20230916_122618.jpg (233.85 KiB) Viewed 1165 times

[PhilC]

I can’t see in the photos what the socket is but there’s a 5V regulator in there so it’s likely the PSU was 9 or 12VDC.

[satjanand]

I can’t see in the photos what the socket is but there’s a 5V regulator in there so it’s likely the PSU was 9 or 12VDC.

Thanks. Would it hurt to just choose one (9V) or the other (12V) and see what happens?

[PhilC]

I can’t see in the photos what the socket is but there’s a 5V regulator in there so it’s likely the PSU was 9 or 12VDC.

Thanks. Would it hurt to just choose one (9V) or the other (12V) and see what happens?

No the 9V should work okay IIRC and mean the regulator runs cooler.