Atari 520ST Repair

[dlfrsilver]

Sorry I got ahead of myself Using the Alt key and arrow keys I can move around the cursor and it makes a sound every time. And using Alt insert can click for me. I opened this screen.


Also I have TOS version 1.0 which is really early correct? Upgrading the ROMS would benefit this system alot I would imagine. What do you guys think?

Ok, thanks for doing the tests. You can use the keyboard so this machine has the usual basic problem (almost all users had this one day) :

The solder on the joystick/Mouse port went dry and broke. the computer is not frozen, the mouse is not responding

Pull out your soldering station and redo or resolder all the pins as shown in the picture i sent above. Next time you launch it, it will run better !
(Then take care of the capacitors, and you will be able to sort the DMA error afterwards).

[dlfrsilver]

If this doesn't work, you can dismount the keyboard, and check for dry solder as well on the mouse and joystick ports (very common problem) :

These pins verault inside the keyboard.

[Verault]

I will definitely check those solder joints out. But I am curious about those DMA errors. What do they mean. Is that a Red Herring?

[siriushardware]

There is a specific IC which is responsible for DMA transfers to and from the floppy drive and the hard drive (if present).

I don't know for sure but I would have thought that the DMA test would require some kind of loopback connector or other specific hardware on the DMA port to succeed, however I don't have one of these diagnostic carts so I can not verify this. Can anyone else?

[siriushardware]

If you look at this page from Best Electronics

https://www.best-electronics-ca.com/stacy.htm

and scroll down to 'Diagnostics' and then further down to "Atari 520ST, 1040ST, Mega 1/2/4, Stacy, 1040STE, MegaSTE, TT and Falcon Computer Diagnostic Loop Test Hardware Test Kit" you will see that a number of loopback cables are mentioned including one for testing the DMA port.

[siriushardware]

If you can drive the mouse pointer around using the keyboard as described by others earlier it is highly likely that you just have cracked solder joints on the pins of the mouse and joystick ports underneath the keyboard. Atari made a token attempt to brace these with a bracket but the reality is that they are 90% secured in place by the solder on their pins, and people had a bad habit of wiggling the plugs in and out of those sockets rather roughly which often led to the solder joints being fractured.

Hopefully that's all it is in this case as well.

If you are unlucky you may have fractured conductors within the mouse cable at the point where it moves around the most, typically just at the point where it enters the plug at the computer end or where it enters the strain-relief at the mouse end.

[Verault]

Just realize I havent updated this. I took out the motherboard and examined the two joystick/mouse ports. With magnification I couldnt see any cracks. I reflowed them all anyway. And yes it now works. The mouse is working!

But going back to my earlier question about the early TOS. Should I upgrade the ROMS on this machine? Can I simply download the roms and put them on an eprom or is it something not pin compatible?

[stormy]

Just realize I havent updated this. I took out the motherboard and examined the two joystick/mouse ports. With magnification I couldnt see any cracks. I reflowed them all anyway. And yes it now works. The mouse is working!

But going back to my earlier question about the early TOS. Should I upgrade the ROMS on this machine? Can I simply download the roms and put them on an eprom or is it something not pin compatible?

Lucky for you there is a forum thread packed with all the information you'll ever need on ROMs / eproms: viewtopic.php?f=15&t=23459

Somewhere in there they cover all the different types.

[dlfrsilver]

Just realize I havent updated this. I took out the motherboard and examined the two joystick/mouse ports. With magnification I couldnt see any cracks. I reflowed them all anyway. And yes it now works. The mouse is working!

But going back to my earlier question about the early TOS. Should I upgrade the ROMS on this machine? Can I simply download the roms and put them on an eprom or is it something not pin compatible?

Yes mouse is working because the solders were broken. For an easy check simply pass a lamp behind the zone where the solders are. You will see the light coming through the cracks.