Curious Amiga 1200 floppy connector modification....

voyager_1701e

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Hi All,
I have some A1200 1d.4 boards that were used for club advertising displays, and it seems some of them had a modification to the floppy connector on the rear of the board. Pin 34 was bridged to pin 2 (which seems to be density select to ready/disc change).

The Amiga would read from external drives no problem, but int (DF0:) would identify as unreadable. I've removed the link on 2 boards, and now the internal drives read OK.

Any ideas what this modification was meant to do?
 

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I think that was part of a modification that allowed pc drives to be used with an amiga. Pc drives could be used only with double density disks.
But i´m not 100% shure.
 
Check the board, top side. Near the clockport header and ram chips. There should be a white-ish sticker!

It should read:

A1200

IT

and loads of random numbers/letters

If that is present then its an Escom AT1200 and has the Panasonic PC-disk drive mod! It can be reversed tho :D

http://www.youtube.com/watch?v=G6fYOjTYvXM

:)

EDIT: Jumping ahead of myself! You have already managed to sort them. Sometimes you have to bridge another set of pins. I may have to do that on an old 1200 here. Last time I pulled it from storage, the internal drive played up but was fine in another amiga. Need to investigate.
 
Last edited:
Check the board, top side. Near the clockport header and ram chips. There should be a white-ish sticker!

It should read:

A1200

IT

and loads of random numbers/letters

If that is present then its an Escom AT1200 and has the Panasonic PC-disk drive mod! It can be reversed tho :D

http://www.youtube.com/watch?v=G6fYOjTYvXM

:)

EDIT: Jumping ahead of myself! You have already managed to sort them. Sometimes you have to bridge another set of pins. I may have to do that on an old 1200 here. Last time I pulled it from storage, the internal drive played up but was fine in another amiga. Need to investigate.

I do remember there are some white stickers on some of the boards (indeed near the clockport / RAM), they had at least "A1200", a barcode and a serial number on them...so you may be right! Im at work now but Ill check it out later. I did try a couple of what I suspect to be PC drives before I took to the wire with snippers :) , but the same result...unreadable.

Thanks for the replies!

---------- Post added at 09:32 ---------- Previous post was at 09:29 ----------

Just checked out the YouTube video (no sound at work damnit!)...and youve identified exactly! I didnt do the other wirelink mod and the drive seems to work fine. Love how this guy uses green jumperwire to blend with the board!
 
I checked out my boards (5 x 1d.4 and 1 x 1d.3). I have 4 1d.4 that have the (photo attached) A1200 UK sticker on them....it actually says A1200 UK then I'm guessing a serial number, on my boards. The 1d.3 and 5th 1d.4 have stickers that are in a totally different place and totally different format and material. 2 of the tested 1d.4 boards after removing the link rectify the floppy issue, neither has had the other link added.

Interestingly all the A1200 UK stickered boards appear to have the E123C E125C timing fix done(actually looks like they were done in the factory, as it looks to be the original solder on the pads). One of the A1200 UK stickered 1d.4 boards is stuffed back into a desktop case, and is working stably with the ACA1232, so I have to conclude it also has the timing fix, as another board which doesn't have the sticker froze constantly after short periods with the ACA installed...after timing mod it worked perfectly.

One board (1d.4) hasn't got any stickers, but I think the board did have an A1200 UK sticker which unglued itself after I took them out of the demonstrator boxes. It has the wire link pin 2-34, and it has the timing fix done...I haven't tested it yet, but I'm sure the floppy wont work...remove the link and it will work! The last board (1d.3) has no link but no timing fixes done.

I think the summation that the boards with the A1200 UK sticker are indeed Escom era boards, and have had the timing fixes already done!

Wow how complex does that all seem! Very interesting all the same!
 

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