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scrappysphinx
11th April 2015, 21:39
Hi all, i have here a Rev 1D4 motherboard that i'm having issues with.

The board boots fine and will boot from HDD but i cannot get it to recognise a floppy.

basically if i insert a disk while in workbench i hear about 3 clicks from the drive as though its trying to read and the DF0????? appears on the screen.

If i remove the HDD i get the boot animation and when inserting a floppy again i hear 3 clicks and the screen goes purple but then returns to the animation.

I have tried the original drive, a known working drive from my a600 before i sold it and a brand new ALPS DF354H090F pc drive that i have converted for amiga use. I have also tried different floppy and power cables. i don't have any external drives to try. I also checked that it wasn't an Escom board that needed a floppy fix.

I did a bit of googling and it was suggested that one the CIA chips may be at fault so i have replaced the one nearest the floppy drive (U8.) with one from from another board but nothing has changed.

There was also a suggestion that Paula might be problematic. I don't know what each is responsible for but i have spares and can replace them. Does Paula have anything to do with floppy functions? Failing that, anyone have any ideas on what to replace next?

Thanks

hooverphonique
12th April 2015, 10:55
there are floppy control pins on both cia's, so if you cannot diagnose the problem any closer, you need to swap both of them.
paula is responsible for handling the actual data coming from the disk, the cia's take care of everything else.

roy_bates
12th April 2015, 10:56
does the motor turn on? and spin.


have a look near or at u26 if youve changed u8

i suggest looking at and/ or getting hold of the 1200 schematics bud.