Mystery Atari ST

[mstreurman]

So I bought a house and moved to Croatia, my wife and I go scavenging every now and then to get old (rotting) wood and bricks for our new garden. Last week we went scavenging again and come across an abandoned building, we speak to the neighbor and she tells us that it has been abandoned for about 25 years and she never sees anyone going in or out and gives us green light to get some bricks. Keep in mind, this house is crumbling and falling apart in so many ways (walls have come down, no roof and so on)

 

So we start looking for some good bricks and while doing that I come across an old Nintendo Entertainment System (NES 8bit), it is pretty beat up but I think I can fix it, so being the computer nerd that I am I decide to bring it. So we go on scavenging, bringing bricks out and into the car until I see something between the bricks. I decide to dig it out to see what it is, the closer I get to it the more I think it is an Amiga 500 (the top is completely smashed, no keyboard and so on...) Once I get it out I cannot see any distinguishing marks at first so I decide it is an Amiga 500 and bring it to the car, I go back in and about 50cm from where I was digging I see something else that looks like a PCB so I decide to dig it out... It is a keyboard with caps missing and no case/shell, upon further inspection of this I see there is some ports (looks like joystick ports to me) and a chip along with some buttons at the top that an Amiga 500 doesn't have. I decide to bring it as I suspect the keyboard and the computer I found go together.

 

Coming home I do a closer inspection and see an Atari logo at the bottom case of the computer but all other stickers are missing. I knew about Atari ST's but I never owned one, nor had I any idea there were so many types.

 

After opening it up I suspect that I have a 1988 Atari STFM, can anyone confirm this? Or tell me what I exactly have here?

 

Would it be worthwhile to try and repair/restore this machine to its former glory? I think it might need a lot of work though:

- New outer shell, as this one has been completely smashed up: I can 3D print this myself if I can find some sort of model for it. (Cost would be around 15GBP)

- New keycaps for the keyboard: I can 3D Print this myself. (Cost would be around 5GBP)

- Maybe a completely new PCB for the keyboard as there are some cracks in it. (I don't know how much this would cost or if I would even be able to source it somewhere or a complete keyboard)

- New PSU as the current one has been completely smashed and the PCB is in 5 pieces (it seems that a guy called Exxos sells these for 35GBP)

- New floppy drive (DSDD 720k?) (It seems that Exxos also sells these for 35GBP)

- New connectors as the current ones are completely rusted up (DSUB/DIN/MIDI and so on around 35-50GBP)

- New capacitors on the mainboard (around 5-15GBP)

- New red thingy marked RP2 on the mainboard (whatever it is, I can tell it is broken as it is cracked in half, 2GBP?)

- Replace the "TV-out" as it is completely broken and rusted.

- Replace the reset(?) button.

- New RF shielding? (I might be able to salvage this one, but it is completely bend out of shape and rusted. 5GBP for the sheet metal)

 

I am asking this as I don't want to waste too much time/money on it, especially since I don't know if I am able to get it into working condition again, but also if it is a "rare" machine I wouldn't want to let the machine go to waste.

[Tillek]

Given half the ram chips are unpopulated and the presence of an rf modulator... 520 STFM

[Zogging Hell]

Yep definitely an STFM. It doesn't look to bad considering how long it's been exposed to the elements (bar some cosmetic stuff on the ports and shifter box). I would almost not be surprised if a new power supply was added whether it would not fire up! Even the keyboard might work with some cleaning up.

[pixelmischief]

Talk about extreme refurbs. Jeez.

[6BQ5]

Wow, what a find!

 

Yeah, I agree that the machine ought to fire right up with a new power supply. Those older designs were surprisingly tough!

 

The old power supply may still work but I wouldn’t trust it to maintain steady voltages after a warming up. Would the power levels drift up/down? Would the capacitors blow out?

 

Clean up the keyboard and add a floppy emulator and you may good to go!

[Zogging Hell]

To answer a couple of your points more specifically..

 

The red thing (if it is one of those long thin things on the motherboard you are talking about) is a resistor pack a.k.a resistor network (presumably that is what the RP is refering to) I believe. You could get a replacement (check the schematics floating around for a value or read from the side if it is still visible) for almost nothing - certainly no more than a pound including postage. Ebay has packs of 15 of assorted values from somewhat dubious Chinese sellers for £1

 

The rusty ports - depends where the rust is, you may be able to salvage them with some rust remover - perhaps vinegar can sometimes help depending on the corrosion as long as you clean/ wash it up after. You could also sand off the larger surfaces. I would just check continuity and whether the port pins are structurally sound - if you don't want to spend too much money. The effect will not be particularly pretty, but no-one will be likely to be gawping at that ST with no case on so shouldn't show anyway.

 

The top RF shielding isn't really necessary, but if you can reshape it, it does help defend against the odd drop of coffee

 

The keyboard - depends on the cracks, if they don't go all the way through there is a good chance it could work. Even if it doesn't they crop up on ebay reasonably frequently. There are some rubbery key caps inside I would be more concerned about rotting, you'll probably want to take all those tiny screws on the back off and inspect the other (in) side as that is where all the tracks and gubbins are .. I would wait, however, until you can power it up before spending a lot of cash.

 

The case - if you really want to 3D print bear in mind it is larger than the average consumer printer in width so you might need to do two halves and 'weld' them together! I think someone on Atari forum may have done something like produced a 3D model (try and search there) - I would try power before doing that though.

 

Seriously the first thing I would do is give it a good clean up, try and clean up the ports as best as possible with some corrosion cleaner and sand off the rest. Replace that resistor pack. Then get a replacement PSU. It's worth getting a new one from Exxos if you have to get one anyway as you would probably want to recap even a pristine on. I would then try the ST and see if it works (you will need to plug the keyboard in, but the floppy can stay out). If it does then hooray, buy some other bits for it. If it doesn't.. well... the ST is probably worth about £30 - £50 in working order with no case (possibly being generous), so you spend more money doing it up than its final value. However, saying that - don't chuck it - as I'm sure someone will be happy to try and fix it up if you decide not to. That ST deserves a better life

[mstreurman]

Ok, I might decide to repair this after all as it seems people are genuinely excited about it. Thanks for the tips and the support already.

 

 

So as I don't have too much money to spend on it, Would I be able to (temporarily) use a PC PSU that I have lying around? I found the schematics to the original one: http://www.gossuin.be/images/schemasatari/Power%20Supply%20SR98.pdfand it seems the power out is just 1x 5v, 3x ground and 2x 12v.

 

If that works, I might do something completely different with it, As the case is broken and printing a new case could become too costly if some of the tolerances are off, I could actually build it in to a (modded) PC case, I can source one of those quite easily. After that it would be trying to make it so I can use the keyboard externally (which doesn't seem too hard) or maybe I could even go and get one of those P/S2 emulators and use a PC keyboard and mouse, get a floppy emulator and add another 512kb of ram... DREAMS

 

but first things first: can I use a PC PSU?

[ParanoidLittleMan]

Ok, I might decide to repair this after all as it seems people are genuinely excited about it. Thanks for the tips and the support already.

 

 

So as I don't have too much money to spend on it, Would I be able to (temporarily) use a PC PSU that I have lying around? I found the schematics to the original one: http://www.gossuin.be/images/schemasatari/Power%20Supply%20SR98.pdfand it seems the power out is just 1x 5v, 3x ground and 2x 12v.

 

If that works, I might do something completely different with it, As the case is broken and printing a new case could become too costly if some of the tolerances are off, I could actually build it in to a (modded) PC case, I can source one of those quite easily. After that it would be trying to make it so I can use the keyboard externally (which doesn't seem too hard) or maybe I could even go and get one of those P/S2 emulators and use a PC keyboard and mouse, get a floppy emulator and add another 512kb of ram... DREAMS

 

but first things first: can I use a PC PSU?

Surely.

[mstreurman]

Do the amperages on the PSU need to be adjusted or could I just run the wires straight to the motherboard? (I can read some basic information from schematics, but it can quickly get too much for me )

If the machine doesn't fry itself, What would be the easiest and quickest way to test it to see if it works?

To see if I have any output DOES the keyboard have to be connected or should it just boot up into TOS?

Easiest way to connect it to a screen would be using the RF-modulator right? I should just be able to find the channel on my Samsung 4k LED TV?

Edited April 9, 2019 by mstreurman

[Zogging Hell]

Not qualified to comment on the PSU but your other queries can have a stab at,

 

All you will need to do for a test is turn it on and wait about 30 secs, the desktop loads from a ROM chip on the motherboard - it waits for a floppy and if it doesn't find one will eventually boot to desktop. Even if you just get a white screen you are probably not too far off.

 

I don't think it will boot properly without the keyboard (I could be mistaken)

 

If your TV can still accept RF then yep that is the easiest. Else in the Euro zone area a ST to SCART cable will be the next easiest.

[6BQ5]

Yes, you can definitely use a big, bulky PC power supply for testing. The ST doesn’t need much power at all so your 100W+ PC supply won’t even feel it. Like you said, be sure to match the proper voltages and grounds to each other and fire it up.