Getting an old Atari ST up and running again—any advice?

[Hari88]

Hi,

I'm currently working on an ST that hasn't been used for years, and I'd like to avoid making a mistake when restarting it. Do you have any advice or a quick checklist for checking the power supply and components before reconnecting? I'd rather ask those who have already struggled with this than burn something out stupidly.

Thanks in advance!

[Steve]

I don't personally think there's much risk in just trying it out, but if you want to be extra cautious I'd maybe take the PSU out and connect it to a load (important!) and measure the voltages.

Then put it back in and turn it on. It may/may not work straight away, don't be worried. Just reseat all socketed chips (you may want to invest in some contact cleaner)

And that's pretty much it. You should be fine...

[rubber_jonnie]

Hi,

I'm currently working on an ST that hasn't been used for years, and I'd like to avoid making a mistake when restarting it. Do you have any advice or a quick checklist for checking the power supply and components before reconnecting? I'd rather ask those who have already struggled with this than burn something out stupidly.

Thanks in advance!

I'd go over the PSU with a fine toothcomb before using it to power the ST, so check damage, capacitor leakage etc, and if you can test with just a dummy load to verify operation first. You can use these as a dummy load: Dummy load resistors

5v is adjustable, but not 12v.

Be aware there are parts of the PSU that operate at very high voltages so the first thing to consider when working with this (Or any) PSU is safety. Be aware you can get a possibly fatal zap off things like the heatsinks, so if you are not confident working with PSUs or feel even a lttle unsure, seek the assistance of somebody who knows what to do.

Similarly go over the mainboard looking for any obvious damage such as scratches, physical damage, leaking caps, corrosion etc I've personally never had leaking caps on an ST mainboard but you should check at least.

If you have a bench PSU the ST will run off just 5v (Some things won't work but it should boot up) but worth testing both 5v and 12v power rails for shorts before applying any power at all.

Obviously if you have a dual supply bench PSU then you can give it both 5v and 12v and potentially use current limiting until you can confirm nothing is getting hot or emitting the magic smoke..

[Hari88]

I don't personally think there's much risk in just trying it out, but if you want to be extra cautious I'd maybe take the PSU out and connect it to a load (important!) and measure the voltages.

Then put it back in and turn it on. It may/may not work straight away, don't be worried. Just reseat all socketed chips (you may want to invest in some contact cleaner)

And that's pretty much it. You should be fine...

Cheers for the reply, that’s actually pretty reassuring!
I’ll probably take your advice and check the PSU voltages on a dummy load first, better safe than sorry.

Really appreciate the tips

[Hari88]

Hi,

I'm currently working on an ST that hasn't been used for years, and I'd like to avoid making a mistake when restarting it. Do you have any advice or a quick checklist for checking the power supply and components before reconnecting? I'd rather ask those who have already struggled with this than burn something out stupidly.

Thanks in advance!

I'd go over the PSU with a fine toothcomb before using it to power the ST, so check damage, capacitor leakage etc, and if you can test with just a dummy load to verify operation first. You can use these as a dummy load: about this website

5v is adjustable, but not 12v.

Be aware there are parts of the PSU that operate at very high voltages so the first thing to consider when working with this (Or any) PSU is safety. Be aware you can get a possibly fatal zap off things like the heatsinks, so if you are not confident working with PSUs or feel even a lttle unsure, seek the assistance of somebody who knows what to do.

Similarly go over the mainboard looking for any obvious damage such as scratches, physical damage, leaking caps, corrosion etc I've personally never had leaking caps on an ST mainboard but you should check at least.

If you have a bench PSU the ST will run off just 5v (Some things won't work but it should boot up) but worth testing both 5v and 12v power rails for shorts before applying any power at all.

Obviously if you have a dual supply bench PSU then you can give it both 5v and 12v and potentially use current limiting until you can confirm nothing is getting hot or emitting the magic smoke..

Cheers for the tips
I’ll have a proper look at the PSU and the board, especially the caps and any gunk or corrosion. Testing with a bench PSU and a dummy load… yeah, didn’t even think of that, sounds like a good shout. I’ll check the 5V and 12V rails before plugging anything in, don’t fancy frying something straight away. And yeah, gotta be careful around the high voltage bits, don’t wanna get zapped.

[rubber_jonnie]

Cheers for the tips
I’ll have a proper look at the PSU and the board, especially the caps and any gunk or corrosion. Testing with a bench PSU and a dummy load… yeah, didn’t even think of that, sounds like a good shout. I’ll check the 5V and 12V rails before plugging anything in, don’t fancy frying something straight away.

I've used the bench PSU on many occasions and you can always start at a low voltage and see what the current draw looks like, and if it's looking OK then work up to 5v.

Definitely worthwhile checking the 5v & 12v rails on the mainboard with a multimeter to see if there's any shorts on the rails.

And yeah, gotta be careful around the high voltage bits, don’t wanna get zapped.

Definitely be careful. Ask me how I know...

[Darklord]

@rubber_jonnie "Definitely be careful. Ask me how I know..."

Don't need to - I laid one bare arm across the towers on the PSU
of a 1040 ST that I was upgrading in the late 80's.

First, last and *only* time I ever did that. Lesson learned. My
arm went pretty much completely numb from my hand to past
my elbow and my fingers clamped shut hard like I was having a
seizure. Ugh.

beaker-electrocuted.gif (196.22 KiB) Viewed 119 times

[rubber_jonnie]

@rubber_jonnie "Definitely be careful. Ask me how I know..."

Don't need to - I laid one bare arm across the towers on the PSU
of a 1040 ST that I was upgrading in the late 80's.

First, last and *only* time I ever did that. Lesson learned. My
arm went pretty much completely numb from my hand to past
my elbow and my fingers clamped shut hard like I was having a
seizure. Ugh.


beaker-electrocuted.gif

Very similar experience to mine. The tingling lasts ages...

[Darklord]

Very similar experience to mine. The tingling lasts ages...

It bloody well will get your attention!

[rubber_jonnie]

Very similar experience to mine. The tingling lasts ages...

It bloody well will get your attention!

Hell yeah!