Sinclair ZX80 / ZX81 / Z88 Forums

I was wondering if there were any currently-available alternatives to the standard wobbly 16K RAM pack? Something that was bigger would be a nice bonus, but mainly I'm interested in something that is smaller and more stable, if it exists.

As well as the offical Sinclair 16K byte RAM pack, there was the 2K/3K/4K ZX80 RAM pack (memory size depending on how many SRAM chips were fitted in it) that would work with the ZX81.

Plus many third party manufacturers that produced various RAM packs.

One of the best known for more stable RAM packs was Memotech, who produced 16K, 32K and 64K versions.

It's possible also to carry out an internal upgrade to 2K or if you can solder even more (8K or 16K being the easiest, but 32K also possible).

In terms of modern expansions, yes there are some, the ZXpand and the Chroma 81 Interface both include extra RAM as well as other facilities.

Mark

Thanks! I have seen the ZXpand mentioned before, and it looks great, although perhaps a bit more ambitious than what I'm looking for. I suppose no one has made a modern RAM Pack without all of the bells and whistles?

The problem with the wobble would probably exist with any RAM pack that used the same method to hook up to the ZX81, I believe. So you would probably be better off trying to find a way to stabilise existing RAM packs.

If you do decide to do an internal RAM modification and you're comfortable with a soldering iron, there is more information here for you...
https://msknight.com/bbc/zx81-ram.html

Pokemon has in the past made modern RAM packs, but I don't think there are any currently available.

There have also been DIY designs.

Mark

In this post I link to an external RAM pack made with modern components.

viewtopic.php?p=45135#p45135

msknight wrote: ↑Sun Apr 28, 2024 7:50 pm The problem with the wobble would probably exist with any RAM pack that used the same method to hook up to the ZX81, I believe. So you would probably be better off trying to find a way to stabilise existing RAM packs.

If you do decide to do an internal RAM modification and you're comfortable with a soldering iron, there is more information here for you...
https://msknight.com/bbc/zx81-ram.html

Here I have to disagree, sorry.
The cause for the wobble are insanely bad edge connectors. Those from the 80s are not tolerable.
New edge connectors are far better offering two independent connections per pin. And they are bent in a way that you can't harm then on plugging in.
I buy them at
https://www.ebay.de/itm/133782296138

I am not related in any way withe the offer or the seller. The link is only to show a reliable seller.

Paul is correct in my opinion. The 80's edge connectors were terrible whereas the modern replacements are far better, one example is of those fitted to Charlie Robson's Zxpands. The white issue 6 I have from him has an edge connector that grips like a vice and like all my other spands suffers no wobble problems whatsoever.

Not anything to do with the topic but apparently 79 "guests" are reading the thread and 520 reading the board at this time!

Paul wrote: ↑Mon Apr 29, 2024 7:27 am Here I have to disagree, sorry.

No need to apologise ... I'm a newcomer to electronics and I'm always willing to learn from people more experienced, like yourself.

Thanks for all of the info! I'm not good with electronics, so I'll probably end up going with something vintage. Can I assume that all of these should also work with the Timex Sinclair 1000?