The internal diagnostic memory checks seem to have passed every time. The results are the same as on my 65XE. One thing I don't understand is that this is represented by two lines of 16 squares, followed by a line of 8 squares. If a RAM chip became faulty, then how would I identify it? I read something about piggy backing RAM, but I'm not sure I understand this.

One change is that, instead of the screen just flashing red, it now stays red for much longer. I've stopped using the 800XL for the moment and will now open up the case, examine it, post and take pics in the hope that there's some sign what's wrong.

BTW, as for my electronics skills at the moment, I've just managed to work out how to take readings which tell me the values of resistors, because the colour codes are difficult to read. I'm trying to build a dimmer switch circuit on a breadboard. This means I couldn't do any more complicated repairs to the 800XL.

Something's happened today which may shed more light on the problems. A few times, the Atari 800XL has powered up with a dark green screen instead of dark blue. Once it changed from green to the usual dark blue all by itself and another time when I pressed RESET it rebooted with the usual dark blue screen. I also got a weird effect while playing the game Mr. M, which is in the Homesoft ATR disk collection. This was that when the player character was going up the screen, it left a trail behind it, which was later erased by going down the screen along this trail. It even happened on the title screen before I pressed the fire button to start. What could cause this?

BTW, the inverse key now seems to be working OK.

I hope to open up the 800XL soon, take some pics and post them on here.

Does anyone know when Silica Shop closed down? I've just done a search and couldn't find a date. I think it was in the early to mid 1990s. I feel I must point out that Silica Shop was in London Borough of Bexley, not Kent, although the Postcode system has never been updated. I should know, because I lived in that area!

As for the lack of pics, I've been thinking about three kinds of technology in two stories. I read a story in a magazine such as "Tales to Astonish", "Astounding Stories", or "Creepy Worlds" where a man bought an old camera, set the lens to 2.0 but found the pictures he got didn't look like what he thought he'd taken. He found out that the number was actually 20 and he'd taken a picture of what was there 20 years previously. He later managed to take pics of himself as a boy and even managed to travel back in time by superimposing a recent picture of himself onto the picture of 20 years before. That's a bit far fetched, though. Something similar also happened in an early episode of Red Dwarf. I also saw something similar done in the series "Continuum", but they were only going back to the night before. I'm looking forward to machines which can produce pictures from brainwaves of memories. Silica Shop was near the corner of Hatherley Road and the High Street. I've actually found a pic of the opposite corner of Hatherley Road dated 1982, when I think Silica Shop was there. So near, but so far!

I now plan to try and do some artwork showing what Silica Shop was like. Look forward to that!

Mclaneinc, on Sat Jun 23, 2012 2:31 AM, said:

I haven't got any pics, but I remember it well. I grew up in that area and often walked past the shop, even before first going in. I remember requesting and hearing a demo of the Atari 800XL sound facilities and I know there was lots of Atari 8 bit related stuff in the shop, such as copies of Antic magazine on the shelves. I never noticed anything about warez going on. They also sold various other computers, including the Acorn Electron, probably all the popular ones, and some that hardly anyone else sold. I bought various items from there, as well as trying out computers, but they didn't like you to try or test them out for too long. I remember typing a few listings into an Amstrad CPC464, before an assistant claimed to have "accidentally" turned it off by pressing the monitor switch while standing behind the computer!

I'd be surprised if there wasn't an article about it somewhere. The local paper was called The Sidcup Times, and the free distribution paper was The News Shopper, so they may have published something about it. I remember seeing a Silica Shop ad in a local paper advertising the Spectravideo 328 in 1984 or later. It said that the Spectravideo 328 was "fairly new to the UK" and that any buyers could join their Spectravideo users' or owners' club. I was upset by this, because that computer had been made obsolete by the MSX standard, which had also been adopted by Spectravideo.

If there are absolutely no photos available, I could try doing some artwork showing what it was like.

Thanks for your suggestions! I haven't opened the case and I've never checked under an Atari metal shield before. I'll try this in the near future.