Floppy write protected (when its not) fix.

Post by **exxos** » Thu Dec 06, 2018 6:10 pm

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This is a shortened version of this thread..https://www.exxosforum.co.uk/forum/viewt ... =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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Video below demonstrating one error without DMA pullups.

Post by **terriblefire** » Mon Dec 31, 2018 5:56 pm

Just made this mod to my STFM

Hasn’t helped my issue but was easy to do

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Post by **PhilC** » Sun Jan 20, 2019 1:09 pm

Just checking, as I dont have any 10k, do you think it will work with 4.7k?

Post by **exxos** » Sun Jan 20, 2019 1:16 pm

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..

DoG · Post by **DoG** » 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.

EDIT: v2.3 booster

Post by **exxos** » Sat Apr 06, 2019 2:30 pm

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

tzok · Post by **tzok** » Fri Jul 31, 2020 10:10 am

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!

pixelk · Post by **pixelk** » Fri Aug 13, 2021 10:28 am

Thank you !

As I didn't have the right resistor network, I built my own.

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Seems to do the trick.

Post by **exxos** » Fri Aug 13, 2021 11:04 am

pixelk wrote: Fri Aug 13, 2021 10:28 am As I didn't have the right resistor network, I built my own.

Wow today's geek award goes to...

FujiMan · Post by **FujiMan** » Thu Aug 18, 2022 8:54 pm

I'd remove the chip, put a precision socket in and place the resistor array on the bottom of pcb.

Floppy write protected (when its not) fix.

Floppy write protected (when its not) fix.

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