Atari 520 st investigation

[MrYo]

Hallo,
I just collected an Atari 520 st and, before to power on it with a new external psu, I want to collect as more info i can about the mods i see. I see the Atonce but I don't know of is correctly installed and something on video shifter with a ribbon cable not soldered and some other mods and wires on the mobo.

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Aso i have a 1040 STe with 4mb of ram, recapped psu, dma board to fix the bad dma problemi, tos 2.06. but after an hour of succesful tests for the dma at the next power on i got a screen full of bombs and now a grey blank screen. But I will make another post for this problemi, with STe photo i have.

Thank for the help.

[mrbombermillzy]

I would be very interested to know what the shifter board with the RAM is about.

[MrYo]

I would be very interested to know what the shifter board with the RAM is about.

Me too, i look for in Google but i find nothing.

[rubber_jonnie]

Well, that seems to be an awful lot of wires that aren't soldered to anything, or is that just the picture?

BTW @MrYo I have removed you from newly registered :) You should be able to post without approval now.

Also, can I ask that you look at Placing photos in a post. and edit your original post so the images are in-line rather than an attachment, thanks.

Shout me if you aren't sure.

[MrYo]

Well, that seems to be an awful lot of wires that aren't soldered to anything, or is that just the picture?

BTW @MrYo I have removed you from newly registered :) You should be able to post without approval now.

Also, can I ask that you look at Placing photos in a post. and edit your original post so the images are in-line rather than an attachment, thanks.

Shout me if you aren't sure.

Yes, a lot of unsoldered wires. The good is that all the mods have sockets so i can test the 520 without the. Anyway there are ofher wires everywhere, some full soldered some half.

Thank you for freedom!

Btw i think a out to buy an oscilloscope, someone can suggest me something? I mean something enough to repair the Atari bit not too much, Atari and 80\90 computer are my goal.

Maurizio

[stephen_usher]

You could get a hand-held, such as the Owain HDS272S which is reasonably “cheap” but the user interface is not as nice as the bench based ‘scopes. It does do a pretty decent job of being and oscilloscope though. Being battery powered it does have the benefit of being not earth referenced and no chance of an earth loop causing something to short through the house wiring.

For my bench ‘scope I have a Hantek, but the bench unit prices have over doubled since I bought mine about 4 years ago.

[sporniket]

Btw i think a out to buy an oscilloscope, someone can suggest me something? I mean something enough to repair the Atari bit not too much, Atari and 80\90 computer are my goal.

Maurizio

For one of my Christmas+Birthday gift, I got myself a DSO2D10 by Hantek from eleshop (I find their price ok, plus not being chinese shop) : https://eleshop.fr/hantek-dso2d10-oscilloscope.html . The price point is not too extravaguant, while having a good specs, it should be able to visualize the 32 MHz master clock of the ST, at least in single channel mode, but I believe that even with 2 channels enabled it should be good enough ; of course no problem at all for every other signals. I also added a pair of x10, 100MHz probes (because only one high bandwidth probe is sold with the scope) : https://eleshop.fr/owon-oscilloscope-probes.html.
Including VAT, the total was almost 300€. (again it was a Christmas + birthday gift)

[rubber_jonnie]

I have an Owon SDS1022 which was quite cheap, under £150, but it does have it's limitations, like a minimum voltage of 50mV, which as I discovered yesterday isn't enough for cassette signals, especially when they come from the 70's...

I think as a scope mine is a bit outdated, but for most scenarios it works great. I do have a Hantek USB scope that uses a PC as a front end and for £60 when I got it it was OK (Especially when used with the OpenHantek software), so with that I get 4 channels altogether, but it's a bit of a faff.

I think if I was buying now I'd opt for a 4 channel scope, but at present I can't justify replacing mine.

Hantek do seem to be a decent brand with sensible pricing, and I'm pleased with my Owon too, so happy to recommend those as brands.

[chronicthehedgehog]

I bought a cheap USB scope of Aliexpress a few years ago. I spent a lot of the time wondering if a) I was using it correctly and b) it was just too crap to give decent results.

In hindsight I wish I'd also bought a cheap signal generator for calibration and learning, i.e. it's probably easier to learn how to use a scope with a known/good signal.

Failing that, I'd choose a recommended scope over something 'random'.