32-bit acorn hardware • Re: HD floppies on A3000/etc. (WDC 1772 overclocking)

Would you mind trying the AJAX chip in the A3000 on its own, without the mod board?

I've just received two of these, from https://www.best-electronics-ca.com/ and they don't even work on their own, for DD discs, when just plugged straight in to an A3000. I'm unable to verify if the ICs themselves work, or if they just don't work with ADFS, in which case I've made a rather expensive mis-buy I'm pretty fed up with this project now.

I have just tried the AJAX chip and here are my results.

Note: the AJAX pictured below does not work for me, but I suspect this one to be a fake or dead chip.


The other one (first revision) gave me mixed results:


It did not work with the original FDD:


but worked with the TEAC drive:


and also with the modded SONY MPF-920 drive, but its behaviour was weird when I tried to access the drive without a floppy inserted.

Your chips should be good, as Brad from Best Electronics is not selling crap.

In the ATARI world, HD Floppy modules use smoothing capacitors in order to allow more WD1772 to be compatible, and they always have a connection to the HD sensor on the FDD.

I will investigate more on that later, as I am quite busy now.

Statistics: Posted by HigashiJun — Wed Feb 28, 2024 6:52 am

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