Atari 800 XL. Rust on the PCB?
 

Good morning. I have to share with you how I am excited I have taken my old computer down from the attic and even more because it works just fine. :)

Maybe it was too optimistic that I just plugged it into the socket and then I looked at what happened. However, later I checked the condition of the PCB. To my unskilled eye, it looks just fine. There was quite a lot of dust, especially in the area not covered by the RF shield, so I cleaned it with a bit of isopropyl alcohol.

The only concern I have is that there is some small amount of rust (???) under the RF modulator. The computer works fine and I don't experience any issues but I wonder if this is something I can leave in this condition or is it something I should take care of immediately. I can't say from my experience because I am a total newbie when it comes to electronics. I would be grateful if you give me some advice. Thank you!

Re: Rust on the PCB?
 

I don't think it can be rust, there's no iron around to oxidise. In fact it looks more like soldering flux to me, in which case it's harmless.

Re: Rust on the PCB?
 

Agree, it's flux which was part of the original soldering process. The modulator is a large metal can which can absorb a lot of heat so the process of soldering those tabs would have required much more heat, solder and flux than on the other solder joints.

Don't worry about it.

Re: Rust on the PCB?
 

The place you need to look is for any memory battery it may have.
Memory batteries are well known for rotting and causing damage to boards and components.

Re: Rust on the PCB?
 

So SiloPhD, we are obviously all curious to know what sort of computer that is?

Re: Rust on the PCB?
 

Looks like the board was wave soldered as it shows some crinkling of the solder mask. It was probably then cleaned with ultrasonic cleaner before the modulator and regulator were hand soldered. I think this is why only a small amount of flux residue left on the pcb.

From what looks like grounding for shields on the pcb I’m going to guess this is from early to mid 1980s.

As SiloPhd is in Poland I might have guessed Sord M5, but they don’t have a regulator on the main board.

Re: Rust on the PCB?
 

Thank you so much for your ideas. In the meantime, I asked my dad and he said it looks like a soldering flux, so now I'm not worried anymore.

It is Atari 800 XL (I thought I mentioned it in my first post but apparently I forgot, sorry ;D). This machine was quite popular in Poland in the late 80s and early 90s. Games were easily available on cassettes and very cheap (between 1989 and 1994 there was no copyright law in Poland as we were in the transition between a communist and a free-market economy), and there was a vibrant demo scene and even a few game publishers like LK Avalon.

I got it in 1994 from my uncle as they bought Amiga and it wasn't fun for them anymore. I had no games unfortunately as it was already 10 years old and cassettes were lost. But I remember I wrote some simple BASIC programs on it and I think it had some impact on me as today I am a software developer. ;D

Re: Atari 800 XL. Rust on the PCB?
 

Quite popular in the UK too, although the Commodore 64 and ZX Spectrum were more so. I sold my Atari on ebay some years ago.

Re: Atari 800 XL. Rust on the PCB?
 

When you said 'shielding' I immediately thought it must be something American made, as the FCC over there were much more aware of the potential for computers to cause radio interference, so Atari computers especially were always well shielded. Even the 'Timex' version of the UK ZX Spectrum sold in the USA had to be properly RF shielded to meet USA regulations, unlike the original ones.

Atari 400s and 800s were not very common in the UK - very nice machines, but not really very affordable here at the time.

It's always great to hear that someone who had one of the first generation of home computers went on to build a career in software development or IT.