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Atari 520ST

VERAULT

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That would be news to me i know there are a bunch of different formats for both drives. 360kb 400 kb and i think 440kb for the single sided drive and 720k and 800kb for the double density.. there may be an 880kb possibly
 

Unknown_K

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It's been a decade, but I think I make bootable ST game disks from a normal PC. The Amiga is the one you can't make disks on a PC (without special equipment).

What makes use of the extra RAM? I have 1MB ST1040 with color and mono monitors and was wondering about that RAM upgrade.
 

VERAULT

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So what do you guys think? Recap the floppy drives? I never worked on these Atari floppy drives before so I am not familiar with all their quirks.

What makes use of the extra RAM? I have 1MB ST1040 with color and mono monitors and was wondering about that RAM upgrade.

I honestly have no idea, I t hought later games needed more RAM but I dont know enough about the ST to say one way or another.
 
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VERAULT

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Well I recapped the sf354 drive and it still wont spin. I even swapped parts from the sf314 and drive mechanisms. Seems the SF354 is fried. Im going to install a gotek into it. I will recap the SF314 though since it still kind of works. If anyone has parts for atari st floppy drives let me know. Pretty sure i just need the motor board.
 

VERAULT

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Can someone please point me to some gerber files so I can print my own Atari ST cartridge with USB power. I am trying to connect up a gotek and this would make for the best implementation.

Yes I know I can buy one, but Id rather build it all myself.

Thanks!
 

SiriusHardware

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If anyone has parts for atari st floppy drives let me know.

It would be better to try narrowing the fault area down through logical fault tracing rather than by playing 'parts darts'.

Here is the service manual for the SF-354.


Service manual for the SF-314.


From the same site as the first item a good walkthrough for the drives generally.


If you need help trying to figure out the fault on one of your drives, pick a drive (the SF-354?) and we can do some checks to show whether the fault does lie with the motor control board or elsewhere.
 

VERAULT

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I hear you certainly but I wasnt looking at throwing money at this thing either. I Was just hoping someone may have some parts drives as I have ZERO spare parts for ATARI ST computers.
 

skate323k137

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Sorry if I missed it somewhere, but does someone have pre-split files of Rainbow TOS 1.04? US would be nice. The whole image appears here:


I have a 6 chip US 1.00 Atari 512ST I'm cleaning up, and I'd love to upgrade it before I put it back together. I have heaps of EPROMS, just need the files.

Edit: found them here https://www.exxosforum.co.uk/forum/viewtopic.php?t=817
 
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VERAULT

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SiriusHardware

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Aren't ST floppies pretty much DOS-format 720K?

Yes and no. The original single sided ST floppies are 360K and are not actually an entirely DOS compatible format so old commercial software sold on floppies formatted in the original proprietary ST format was and still is not readable or writeable with a contemporary DOS machine - not without using a specific bit of software to do it.

By the time of the 'Rainbow' TOS (1.04), this had been tweaked so that floppies formatted by that ST OS could be read from and written to by a PC and floppies formatted by a PC could be read from and written to by an ST, so this is another benefit which Verault has gained simply by updating the OS.

Of course to read from and write to 720K floppies the ST has to have a double sided drive - early STs did not, later ones did. A machine which is old enough to have had TOS 1.0 from new is quite likely to have a single sided drive, unfortunately.
 

Chuck(G)

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Ah, that's why I replaced the SS external drive on my 520ST with a homebrew two-drive double-sided set (NEC 720K drives, I believe). Back then the only major issue was the boot sector contents.
 

SiriusHardware

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The 520STFM I have here is my original one from about 1986 and it did originally have both TOS 1.0 and a single sided drive. I soon fitted TOS 1.04 in 6 EPROMs and a DS drive internally but the specific ones with the Atari ST form factor (wide, rhombic eject button) were not widely available here in the UK so I fitted a compatible 720K PC drive for which I had to carve the right hand end of the ST's top cover to expose the drive's small PC style eject button. I wasn't very happy about having to do that at the time but the need for the double sided drive was greater than any aesthetic consideration.

My STe, which is a couple of years younger, came with a double sided drive so it was never necessary to butcher that one in the same way.
 

skate323k137

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Im in the throws of trying to repair my 520ST. I have all the components to fix the keyboard. As of now the unit boots to TOS and immediately freezes. Im building a Diagnostic cartridge. Can someone tell me the most comprehensive diagnostic software for cartridge out there? Is there any new diag software still in development. Im pretty much a noob with Atari ST's. Ive got the basic eprom cartridges out there with 4 X 27c256kbit eproms on them that looks like the image below.
View attachment 1258040
I'm looking at throwing a few games on this PCB for the time being, because I have some roms and PCBs on hand, but no HDD or FDD for my 520STM. Not a long term solution, but a fun project I hope.

There are some games prepared mostly here. It looks like the program needs ROM3 and ROM4 space but starts in ROM3. I find it interesting the diag cart uses ROM4 and not ROM3 space but I don't want to over think that.:

In the downloads at the bottom of the page, there are ROM files you can split. As instructed I removed the 4 zero byte header, and as a result it then starts with the proper program string (ABCDEF42).

I looks like he uses some simple chip enable logic to condense to 27C512s but that should not be a big deal, I can split to 23c256's instead for this PCB I think.

At that point, I split that ROM into hi/low portions with a simple python script. The resulting files however were 64k, and I need 32K roms, so I split those in actual half (not byte wise).

I'll report back if this works out, I've split Xenon into the 4 files and we will see how it goes.
Code:
#Remove 4x leading 0 bytes from .STC file to get .ROM file. Then:
$split -b 32768 Xenon_high.ROM
$mv xaa Xenon_high_03.ROM
$mv xab Xenon_high_04.ROM
$split -b 32768 Xenon_low.ROM
$mv xaa Xenon_low_03.ROM
$mv xab Xenon_low_04.ROM

Code:
-rw-rw-r--@  1 alex  staff  131076 Sep  1  2014 XENCRT2.STC
-rw-r--r--@  1 alex  staff  131072 Nov  8 22:47 XENCRT2.ROM
-rw-r--r--   1 alex  staff   65536 Nov  8 22:48 Xenon_high.ROM
-rw-r--r--   1 alex  staff   65536 Nov  8 22:48 Xenon_low.ROM
-rw-r--r--   1 alex  staff   32768 Nov  8 23:58 Xenon_high_03.ROM
-rw-r--r--   1 alex  staff   32768 Nov  8 23:58 Xenon_high_04.ROM
-rw-r--r--   1 alex  staff   32768 Nov  8 23:58 Xenon_low_03.ROM
-rw-r--r--   1 alex  staff   2768 Nov  8 23:58 Xenon_low_04.ROM
 
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skate323k137

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Very cool. But since the board uses 27c256 eproms these will be cut in half?
Exactly; the script logic I used originally splits them to High / Low which are the size of a 27C512. (https://github.com/dh219/Hi-Lo-Byte-Split). Once I run split -b on those, The resulting 32k files should fill 4 27c256's perfectly.

If this works, it should work for the whole handful of games on that site.
 

skate323k137

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Let us know. I wasnt aware of anyone getting games on cart for the ST so this is kinda fun.
I think I'm getting there. I did one thing backwards, Rom4 does come before Rom3 in address space, but this is easily fixable at this stage by just renaming the files right since I haven't burned any chips yet.

"Two sockets are for the ROM4 area (0xFA0000 to 0xFAFFFF), and two sockets are for the ROM3 area (0xFB0000 to 0xFBFFFF)."

So it's the beginning of ROM4 which needs the magic string, and data should spill over to ROM3 space. I'll solder up a socketed cart and let you know how it goes.
 
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skate323k137

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Xenon works. I programmatically split the rest and ran Xenon thru the same script to ensure it came out the same as when I did it manually. These -should- all work:


Here is my cart next to the nice diagnostic cart from @VERAULT , and "Pics or it didn't happen."

20231109_170751.jpg20231109_172144.jpg
(not actually a PS2 joystick, it's wired common ground with no brains).
 
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