exxos's Atari, Amiga & retro forum

embarassingly simple help required please

I've been trying to install a few bits I recently purchased from the exxos shop. I managed to fit an exxos upgraded CPU and TOS2.06 upgrade kits without any issues. Unfortunately I've hit a dead end fitting exxos 4 meg memory upgrade [0024] which i thought would be simplest job of all!

None of the new simms ever get recognised, either as one or two pairs and when tried with / without the factory ram. Yes, I'm pretty certain the new ram was properly seated in the multiple tests and combinations I tried. My 520 STE has motherboard CA4003290, no extra rev markings visible andvhas the black coloured simm slots. The machine came with two full simm slots and two empty. There's no sign the machine had ever been opened nor any sign of damage / previous mods to the board or slots. I've proved the "empty" slots by installing my originals simms plus two leftover from a friends 1040 STE upgrade. The machine runs stable with 1.5meg reported.

I can't find any mention of motherboard specific limitations with memory upgrades nor any mods being required as part of the installation. I've done the obvious, cleaned contacts, checked up close for any sign of pin damage but it makes no difference. I don't have the luxury of trying these in another machine so I'm stuck for ideas and hoping i've overlooked something stupid. Any ideas welcome! ... thanks in advance, Ed.

You may be falling victim to the "bad sockets" thing. The problem with the simms from like the 1990s etc, they were to thick for the sockets. Plus the solder on them widened the contacts even more which doesn't help. So when you put in new simms, which are currently 1.2mm , unfortunately doesn't "fit" is the previous simms have widened the socket to 1.5mm+.

I have a new batch of simms in the making which should fit better, these are custom 1.4mm thick PCBs ( also more expensive unfortunately) which should fit better on "worn" sockets. I can swap them with yours if you return them, but they haven't got manufactured yet and could be a few weeks before I get them.

Thanks for the quick response - it's certainly worth a try and a few weeks (or longer) it absolutely fine.
Do you want me to return these now so they are back with you while waiting for the thicker ones ?

Is there a link to return details somewhere ?? thanks, Ed.

I've sent you a PM.