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Atari 520ST

VERAULT

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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.
1701554467477.png
 

SiriusHardware

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I don't know whether you have already been there but you might have more luck on the atari-forum.com forum which is specific to the Atari ST, STe, Falcon and TT machines. If anyone has written custom diagnostic firmware for these carts, they most likely hang out over there.

There are a lot of people with really in-depth knowledge of these machines there.

 

masteries

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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.

Here is the Atari ST boot up sequence:



As well, Atari ST/E requires a floppy drive to correctly initialization;
if the floppy drive is not connected or it doesn´t respond properly
the computer turned freeze.


*Note: Respond properly doesn´t mean that the drive is capable of use floppies, this mean
that there is a floppy drive controller at the other end of the floppy cable.




In terms of Atari ST/E repairing, the better place is Exxos forum;
its a place dedicated only to repairing:

 

SiriusHardware

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Verault: After a shaky start, someone over on Atari-Forum did answer your question about the code which needs to go into your diagnostic cartridge, at least as far as the official Atari diagnostic code which originally went into these is concerned. You may have to enquire further if you find you need something which tests a particular area of the machine more comprehensively.
 

VERAULT

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Verault: After a shaky start, someone over on Atari-Forum did answer your question about the code which needs to go into your diagnostic cartridge, at least as far as the official Atari diagnostic code which originally went into these is concerned. You may have to enquire further if you find you need something which tests a particular area of the machine more comprehensively.
Thanks for the heads up. I just went over and downloaded the file they linked! (y)
 

SiriusHardware

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I see you got some useful hints about how to move the mouse pointer using the keyboard keys as well. It is incredibly common for ring-shaped cracks to appear on all of the solder joints on the joystick / mouse ports on the underside of the keyboard, rendering the mouse inoperative - so if you can move the mouse pointer by holding down the ALT + arrow direction keys but you can't move it using the actual mouse, that would be your first port of call, if you'll excuse the pun.
 

VERAULT

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I see you got some useful hints about how to move the mouse pointer using the keyboard keys as well. It is incredibly common for ring-shaped cracks to appear on all of the solder joints on the joystick / mouse ports on the underside of the keyboard, rendering the mouse inoperative - so if you can move the mouse pointer by holding down the ALT + arrow direction keys but you can't move it using the actual mouse, that would be your first port of call, if you'll excuse the pun.
Yes I didnt even know this was possible. Little tidbits like that are invaluable. Capacitor and crystal conjecture... not so much.

Thanks for jumping in by the way.
 

mbliss11

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Mine has like

Mine has like 6 rom chips but I have seen others replace the whole row with just 2 eproms. How was it for you? did you just buy a kit or burn the eproms yourself?
I have an early 520 and it had 6. I just bought a kit. I also did a 4 Meg ram upgrade as well
 

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VERAULT

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I have an early 520 and it had 6. I just bought a kit. I also did a 4 Meg ram upgrade as well
Yeah thats pretty much the same as my 520. I think the TOS is ver 1.0 . Its Very nice now. Can you send me the link to where you got the RAM from?
 

mbliss11

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That website is a bit crazy, you have to buy it all in individual components?

£37 for the ram board Plus £24.00 for the shifterboard Plus £5 for the ram cable? Is that how you purchased it? Thats £66 before shipping, It could easily be over $100 USD all said and done. Unless I am reading the site wrong.

Yea website is a little hard to follow but I believe I just got the shifter board pcb and assembled myself and saved a few bucks. The pcb was only like 5 euro. It’s certainly not cheap but it has been 100 in my system and has good track record. My revision board also had to remove all ram from the board in order to isolate it there was no known way to isolate without doing that. It puts less stress on the power supply. So it’s a bit of a job
 

VERAULT

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Yea website is a little hard to follow but I believe I just got the shifter board pcb and assembled myself and saved a few bucks. The pcb was only like 5 euro. It’s certainly not cheap but it has been 100 in my system and has good track record. My revision board also had to remove all ram from the board in order to isolate it there was no known way to isolate without doing that. It puts less stress on the power supply. So it’s a bit of a job
Oh really. That is something else to consider though. I can tell at a half of a meg of ram I cant run much on it.
 

SiriusHardware

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There isn't actually much original commercially written software which REQUIRES 1MB of RAM, because as with all other cases of 'enhanced' machines the ones with the larger memory size suffered from lowest-common denominator syndrome, that is, it didn't make sense to write software that only a small subset of Atari ST users would be able to buy and run, therefore the vast majority of software titles, certainly games, were written to run on a 512K machine and could also run on a 1MB, 2MB, 4MB machine. A very few 512K compatible titles did offer enhanced features if they found 1MB of RAM present.

The sort of software most likely to demand more RAM falls into two categories, serious (productivity) software like some of the high-end MIDI sequencer titles, etc - and anything produced by demo / cracking crews, as they tended to want to pack as much in as possible, so demos and 'menu discs' requiring a double sided disc drive and at least 1MB or 2MB or more of memory are fairly common.

My 1986 Atari STFM came with TOS 1.0 but has for most of its life had the 'Rainbow' TOS (1.4) primarily because (HDD) (via DMA) disc operation was rather sluggish under TOS 1.0 and much quicker under TOS 1.4 - I can say this because for a time I had both versions of TOS in the machine so it was easy to flip between them and see the difference.

My STFM has TOS in 6 x ROMs and I directly replaced the original PROMs with 6 x 27256 EPROMs.

There is however one reason to favour TOS 1.0, especially if you don't plan to use an HDD or anything which pretends it is one - compatibility with a wider range of original software. A fair few titles which were written to run under TOS 1.0 found themselves broken when they tried to run on an upgraded machine - to give just one reason why, the system variables containing the mouse 'x' position and 'y' position aren't in the same RAM location in every TOS, but software writers working with TOS 1.0 (when there was no later TOS) assumed they would be. I have an original copy of the breakout clone 'Arkanoid' which came with my machine and worked with it when it had TOS 1.0 but stopped working under TOS 1.4. (Later releases of Arkanoid had this problem fixed). Software written during the later period was 'aware' of earlier TOS versions and written to work with all of them, but some software written during the early period may in some cases be hard coded to run under TOS 1.0, therefore it follows that (strangely) the most widely software-title compatible TOS is the oldest one.

You can solve this dilemma by doing what I did for a while, I programmed TOS 1.0 into the lower halves of 6 x 27512 EPROMs and TOS 1.4 into the upper halves, with the highest address pin on all 6 EPROMs bent out horizontally from the socket, all connected together and connected to a switch arranged to pull them all low (TOS 1.0) or pull them all high (TOS 1.4).

I eventually decided to run TOS 1.4 only, since there was only the one software title (that I personally owned) which would not work under TOS 1.4.
 

mbliss11

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Joined
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Messages
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Location
Maryland
There isn't actually much original commercially written software which REQUIRES 1MB of RAM, because as with all other cases of 'enhanced' machines the ones with the larger memory size suffered from lowest-common denominator syndrome, that is, it didn't make sense to write software that only a small subset of Atari ST users would be able to buy and run, therefore the vast majority of software titles, certainly games, were written to run on a 512K machine and could also run on a 1MB, 2MB, 4MB machine. A very few 512K compatible titles did offer enhanced features if they found 1MB of RAM present.

The sort of software most likely to demand more RAM falls into two categories, serious (productivity) software like some of the high-end MIDI sequencer titles, etc - and anything produced by demo / cracking crews, as they tended to want to pack as much in as possible, so demos and 'menu discs' requiring a double sided disc drive and at least 1MB or 2MB or more of memory are fairly common.

My 1986 Atari STFM came with TOS 1.0 but has for most of its life had the 'Rainbow' TOS (1.4) primarily because (HDD) (via DMA) disc operation was rather sluggish under TOS 1.0 and much quicker under TOS 1.4 - I can say this because for a time I had both versions of TOS in the machine so it was easy to flip between them and see the difference.

My STFM has TOS in 6 x ROMs and I directly replaced the original PROMs with 6 x 27256 EPROMs.

There is however one reason to favour TOS 1.0, especially if you don't plan to use an HDD or anything which pretends it is one - compatibility with a wider range of original software. A fair few titles which were written to run under TOS 1.0 found themselves broken when they tried to run on an upgraded machine - to give just one reason why, the system variables containing the mouse 'x' position and 'y' position aren't in the same RAM location in every TOS, but software writers working with TOS 1.0 (when there was no later TOS) assumed they would be. I have an original copy of the breakout clone 'Arkanoid' which came with my machine and worked with it when it had TOS 1.0 but stopped working under TOS 1.4. (Later releases of Arkanoid had this problem fixed). Software written during the later period was 'aware' of earlier TOS versions and written to work with all of them, but some software written during the early period may in some cases be hard coded to run under TOS 1.0, therefore it follows that (strangely) the most widely software-title compatible TOS is the oldest one.

You can solve this dilemma by doing what I did for a while, I programmed TOS 1.0 into the lower halves of 6 x 27512 EPROMs and TOS 1.4 into the upper halves, with the highest address pin on all 6 EPROMs bent out horizontally from the socket, all connected together and connected to a switch arranged to pull them all low (TOS 1.0) or pull them all high (TOS 1.4).

I eventually decided to run TOS 1.4 only, since there was only the one software title (that I personally owned) which would not work under TOS 1.4.
Great info!

For games hd images are generally preferred and for those hd modified games they generally require at least a meg of ram. If you are just using disk images you can go further with only 512k. I was originally going to go that route but the st that I added to my collection didn’t have an internal disk drive. Making a floppy cable for my gotek with that crazy million pin din connector did not sound fun to me and buying one was close to getting an sd hd card solution
 

VERAULT

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Great info!

For games hd images are generally preferred and for those hd modified games they generally require at least a meg of ram. If you are just using disk images you can go further with only 512k. I was originally going to go that route but the st that I added to my collection didn’t have an internal disk drive. Making a floppy cable for my gotek with that crazy million pin din connector did not sound fun to me and buying one was close to getting an sd hd card solution
I guess that explains it. I got one of those hdd emulators for my ST. It came with a couple folders one labed 1mb one 2mb I guess now i know that means RAM needed. eithsr way all the games wont load. even the utils keep telling me i need more ram.
 
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