Fitting the 'ralcool HD floppy modification' [loads of pics]

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spiny
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Fitting the 'ralcool HD floppy modification' [loads of pics]

Postby spiny » Mon Jul 26, 2010 10:15 pm

Hi all,
I thought I'd do a picture heavy thread showing how I fitted the high density floppy mod as supplied by the esteemed forum user 'ralcool' :) it's a tidy piece of kit and the instructions he supplies can even be followed by an electronics thickie like me :)

supplied in my kit were:

1x board with header pins
1x TOS ROM chipped patched to allow 3ms step rate
8x header pin ends
1x useful instructions containing photos

ralcool suggested that I use a 6 chip TOS FM for the mod, so thats what I grabbed from my pile of Ataris.

Lets begin:

First up, open the Atari and remove all the shielding. Then locate the floppy chip and cut the right pin:

Image

Then solder a wire to the pin, this is where the 8/16 clk signal is:
Image

The mod needs 5v - this is taken from pin 40 of the video shifter:

Image

Next up is the 16mhz signal from pin 39 of the video shifter:

Image

DS1 signal is taken from pin 19 of the soundchip:
Image

lastly for the motherboard, a GND is needed, pin 20 of the video shifter can be used (not a good pic)
Image

you also need a HD detect signal and a HDD0 signal, both from the floppy, this sony drive couln't supply a stable HD detect annoyingly:
Image

so this compaq/nec unit was used instead:
Image

as is the case with most modern drives, it didn't have a drive select jumper, but did have a little solder pad thet i bridged:

Image
Image

finally, solder all the 'ends' to the wires and attach to the board:
Image

now is a good time to check it all works, using the AUTO folder prog supplied:

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if all is well, install the patched ROM:

Image

the result should be the handy ability to boot using HD disks :)

Image

the mod handles all the switching too, so you can carry on using the DD disks and HD disks at the same time, no need for switches or reboots.

huge thanks to ralcool for making this kit and giving me help fitting it, despite an 11 hour time difference :D

hope you all enjoyed this thread, I had fun installing the kit and it'll make life a bit easier :) note to the more experienced electrickery types, yes, I did shorten all the wires once I knew it all worked, it's a lot tidier now and secured with the magic glue gun :)

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Re: Fitting the 'ralcool HD floppy modification' [loads of p

Postby ralcool » Tue Jul 27, 2010 2:39 am

Again. Great job Spiny. :thumbs:

The TOS patch is for TOS1.4, and allows driverless HD operation without using a program to set 6ms FDD step rate. It only affects one ROM as seen.

This is the little board I will be making another half dozen or so.

:cheers:

Sean
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Re: Fitting the 'ralcool HD floppy modification' [loads of p

Postby Xerus » Tue Jul 27, 2010 2:45 am

It's a good work, bravo :thumbs:

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Re: Fitting the 'ralcool HD floppy modification' [loads of p

Postby wongck » Tue Jul 27, 2010 11:59 am

Great work.
My Stuff: FB/Falcon CT63+CTPCI_ATI_RTL8139 14+512MB 30GB HDD CF HxC_SD/ TT030 68882 4+32MB 520MB Nova/ 520STFM 4MB Tos206 SCSI
Shared SCSI Bus:ScsiLink ethernet, 9GB HDD,SD-reader @ http://phsw.atari.org
My Atari stuff for sale - click here for list

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Re: Fitting the 'ralcool HD floppy modification' [loads of p

Postby Shredder11 » Tue Jul 27, 2010 9:46 pm

Love the photos, great stuff! :thumbs:


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