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Re: My OSI 610 build - Expansion for the OSI 600
Posted: 19 Jun 2025 11:43
by HigashiJun
I guess it's the ELK...
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 19 Jun 2025 11:47
by rubber_jonnie
HigashiJun wrote: 19 Jun 2025 11:43
I guess it's the ELK...
Elf :)
Cosmac ELF II replica
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 19 Jun 2025 13:17
by stephen_usher
rubber_jonnie wrote: 19 Jun 2025 11:08
Would you believe that I already have one lined up...
Surely not! Hehehe!
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 19 Jun 2025 13:18
by PhilC
stephen_usher wrote: 19 Jun 2025 13:17
rubber_jonnie wrote: 19 Jun 2025 11:08
Would you believe that I already have one lined up...
Surely not! Hehehe!
I'd be surprised if he only had one lined up :lol:
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 19 Jun 2025 13:59
by rubber_jonnie
PhilC wrote: 19 Jun 2025 13:18
I'd be surprised if he only had one lined up :lol:
It's true, I do have more than one lined up, and may add an Atom replica to the mix, which is your fault
@PhilC :dualthumbup:
I am also looking to build a ZX80 replica too.
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 20 Jun 2025 01:31
by HigashiJun
Oops, my bad...
From:
ELK.jpg
To:
ELF.jpg
8-)
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 20 Jun 2025 09:16
by rubber_jonnie
HigashiJun wrote: 20 Jun 2025 01:31
Oops, my bad...
From:
ELK.jpg
To:
ELF.jpg
8-)
:lol:
:girldance:
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 20 Jun 2025 11:25
by rubber_jonnie
Not content with getting it all working, I'm modding it to support double sided drives, meaning each FDD treats a side as a disk. Should be interesting, and apparently it also supports 2 drives, so ultimately drives A to D.
More later.
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 22 Jun 2025 11:16
by rubber_jonnie
OK, so the double sided mod is done :)
The mod is done in this corner of the 610 board indicated by the red square:
Screenshot 2025-06-22 at 10.44.14.png
You can see a number of square jumper pads. The links and cuts (X) on top are shown here in
green:
Topside_2.jpg
It's necessary to add a 1K resistor at R7. The underside cuts are shown here in
red with the topside cuts (X) and links in
green:
Screenshot 2025-06-22 at 11.02.05.png
The main difference once this is done is the need to use a floppy cable with a twist rather than a straight through one.
I need to download some double sided disk images to test, but basically it means that my Gotek (or any other double sided drive) will work as 2 drives, so A: & B: with each head being a 'drive'. If I add a 2nd drive it will work as C: & D: in the same manner.
It's a bit like double sided drives for the BBC B.
More testing to be done but it is happily booting from the Gotek as before with the new cable, so I haven't broken anything :)
Re: My OSI 610 build - Expansion for the OSI 600
Posted: 01 Jul 2025 13:40
by rubber_jonnie
OK, so I have been able to finish off assembly of the 600&610 with the arrival of some rubber feet today:
IMG20250701113257.jpg
IMG20250701115542.jpg
It's all buttoned up in an OSI sandwich :)
And I have a pair of Goteks working double sided:
IMG20250701133759.jpg
IMG20250701133804.jpg
It is also sort of working with a 5.25" floppy drive, but it's not 100% so more work to do on that.