Hi.

OK. Here's the deal. I have a design for a memory upgrade board for Mk2/2A boards which (although I haven't yet built a prototype) I'm pretty sure will work quite nicely. After much thought, I was unable to come up with a good way of getting it above 64MB, but that should be sufficient for most people. I had hoped for 128MB, but it turns out to be pretty much undoable.

It would be possible to add other things as well, but after talking it over with Hugo we decided there wasn't all that much point. I had considered both 100mbit ethernet and USB host, but dumped them for various reasons:

1) the data rate from the USB host controllers suitable for use in this application are dreadful, according to Hugo, and the controllers consume enormous amount of idle bus cycles, thereby slowing things down.

2) for a number of reasons that have been thoroughly explored in past discussions, 100Mbit ethernet in this application wouldn't really achieve much that 10Mbit doesn't, and complicates things quite a lot.

3) There are supply problems with some of the parts for both USB and ethernet

4) It may well not fit anyway.

So, the current plan is for a PCB which will fit to the underside of the main board, attaching to the test points. It will have 8 64Mbit DRAM chips giving a total of 64MB of ram, and will require one patch wire. On a MK2A you could omit the wire and still get 48MB. On a MK2 you will have to remove the chips currently fitted to get the full amount.

It is a completely surface mount device, and would as such not really be suitable for selling as a kit. I will therefore have to get the things made in batches as completed sub-assemblies, which will then need to be fitted by one or other of the prople floating around who are good at such things.

I am provisionally aiming at a price of about £90-100, and the advantage of doing it this way should be shorter lead times and less supply problems than the tuner kits have. So far, I have contacted a company who can do the assembly, have routed the PCB, and I'm waiting for a quote on quantities of the RAM and on manufacture of the boards.

Anyone interested?

Pca

I'll take one!

Note about 100mb/s ethernet: with more memory, the underlying assumptions have changed, and it would now be able to have a more noticeable impact on I/O due to Linux's caching (which now has more memory to play with).

Cheers!

Drooooool.

I'll take 2 please Patrick. And someone to install them

Yep, I'll take one.

Do you still have to remove the original chips for a Mk2a? I assume yes but you only mention that it's necessary for the Mk2 in your post. If not, the original chips are redundant, right?

And there is enough room underneath the PCB right? I don't remember huge amounts of space between the board and metal case but we are talking only one surface mount chip thickness plus PCB (~3mm?)

I am, of course, interested. Four, please. But, a question: what does this do to people with enhanced memory via the stacking method? Does all of the memory need to be removed?

I'll take two.

The board adds 4 identical banks of 16MB, and duplicates the bank0 set currently present on a MK2A. Obviously, this isn't going to work all that well. The idea is that each bank can be disabled by means of a switch on the memory board, so in the case of a MK2A you would turn off the first bank. This would still give you 64M, as the original memory would be used.

As for room, there's a whole 2.5-3mm available! 0.8mm for the PCB, 1.2mm for the chips, 0.1mm for the insulator sheet on each side of the PCB, and loads of room left over

pca

Well, if you've already butchered your poor board, you could disable the appropriate banks on the expansion board to compensate. I would recommend removing the added stacked chips, but it shouldn't be absolutely necessary. You would still only have 64MB though.

pca

Ah, my board has been hacked a few times already - digital out, illumination hack. The memory was just the most recent. Still, if it is a matter of only gaining an extra 16MB over the existing 48, it may not be practical. Still, I would like to get the boards anyway, just in case I run into trouble later on.

I'll also take two.

I'll take one, please Sir.

I'm probably in for two or three at least.

I'll take two of the boards.

I'll take one as well, thanks!

I would order two

I'm in for 1, maybe 2.

Count me in for 2.

OK, so it looks like my initial test batch of 25 is gone already! I may have to do a bigger initial set.

I have heard back from the memory supplier, and the chips are in stock and rather cheaper than I feared. So that's all right then.

Just the PCB to go now.

pca

I'll take one. I will have the person that repaired my other chips (many times) do the surface mount soldering for me.

It really sounds much better than stacking and having 6->3 patch wires dangling around.

Count me in for one of those.

I'm very much interested, I have an original MK2 player.

I'll take at least two!

count me in for two

Hmm, a hundred quid for another 32MB of memory. Takes me back ten years! For that sort of price I would struggle to justify it to myself... (Says the man who's just dropped £100 on new headphones )

count me in for one as well, thank you :-)

i've got a MK2 in case you need to know that as well.

greg

Count me in for one as well.

Need you ask? I'll take two, and I'm prepared to install/test them also.

You have to know Patrick....

I guess he's protective of his babies. I wonder how he'll feel when I completely disassemble a Mk1 mainboard.