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Floppy write protected (when its not) fix.

Posted: Thu Dec 06, 2018 6:10 pm
by exxos
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This is a shortened version of this thread..viewtopic.php?f=23&t=1410

The issue was with a STE machine, which was continuously or intermittently reporting the floppy was write protected when it was not.

The assumptions are the drive has been tested and working fine in another machine. It is also assumed that the WP pin on the 1772 is always high (for write enabled operations).

The fix for this issue to solder a 10K bussed resistor array to the 1772 databus pins as illustrated below.

The white wire connects the common pin on the resistor array to 5V.
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Re: Floppy write protected (when its not) fix.

Posted: Mon Dec 31, 2018 5:56 pm
by terriblefire
Just made this mod to my STFM

Hasn’t helped my issue but was easy to do




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Re: Floppy write protected (when its not) fix.

Posted: Sun Jan 20, 2019 1:09 pm
by PhilC
Just checking, as I dont have any 10k, do you think it will work with 4.7k?

Re: Floppy write protected (when its not) fix.

Posted: Sun Jan 20, 2019 1:16 pm
by exxos
Forgottenmyname wrote:
Sun Jan 20, 2019 1:09 pm
Just checking, as I dont have any 10k, do you think it will work with 4.7k?
Assume would be ok..

Re: Floppy write protected (when its not) fix.

Posted: Sat Apr 06, 2019 2:28 pm
by DoG
Did this on a STfm (070789-001 RevD) since I fitted 2.2 booster on it and having problem reading disks. Works perfectly now.

EDIT: v2.3 booster

Re: Floppy write protected (when its not) fix.

Posted: Sat Apr 06, 2019 2:30 pm
by exxos
DoG wrote:
Sat Apr 06, 2019 2:28 pm
Did this on a STfm (070789-001 RevD) since I fitted 2.2 booster on it and having problem reading disks. Works perfectly now.
Thanks for letting us know :thumbup:

Re: Floppy write protected (when its not) fix.

Posted: Fri Jul 31, 2020 10:10 am
by tzok
This fix solved my issue with ACSI CF adapter in 1040 STfm. Before, it was writing complete garbage on the CF card, after applying this fix - works like a charm!

P.S.
Thanks to tOri from atari.org.pl, I probably have a fully working ACSI to CF adapter for ST. And it is fast - 1.8 MB/s on stock ST.