Emax

> A few comments.
>
> ("What I'd be inclined to do is just copy the EEPROM
> from the 8M machine")
>
> Last time I looked the EEPROM was soldered to the board you mean to tell
me that someone wiling to sacrafice a perfectly working EmaxII to an
overheated pc board when removing the chip let alone loosing the chip?

Overheated PC board?  I replace soldered-in IC's on both through-board and
surface-mount assemblies on a fairly regular basis.  I remember toasting a
ZX Spectrum main board once, the first time I tried to do this (around 15
years ago).  Since then I seem to have done it without too high a mortality
rate.  I'm not even particularly good at it.

> ("The PALs can be easily reverse-engineered.  Quite simple.  Pull the PALs
> from a known good 8M Emax II, power them up on a test bench, then feed
> inputs in and see what comes out. ")
>
> I can verify beyond a shadow of a doubt that the PALs from Emu have the
fusible link blown.
> this means that you can't just read the PAL. By testing IO you may solve
the logic but will you solve the RAS & CAS timing issues associated with the
dynamic ram timing?

Yep, you can't read them through the programming port.  Testing the IO would
be the way to do it.  DRAM timing is a bit of a black art, but nowhere near
as critical as you might think.  Certainly, not at the relatively low speeds
the Emax goes at.  In any case, looking in a Maplin catalogue, 1M x 8 bit
CMOS SRAM's are less than \ufffd4, so you're talking about \ufffd30 or so.  That would
solve all the timing problems...

> The other problem is that the EmaxII is obsolete. Useful yes but not
necessarily worth such a gallant effort. I have purchased EmaxII racks with
8mb for as little as $120.00 and I beleive that as they go by the wayside
that you will find the parts you need to convert the EmaxII without the
extended effort.

I *really* wish I could get an Emax II for that in the UK.  Mine cost \ufffd130,
and it's only got 2M... I did get two Syquest drives with it though.
If you've got an Emax II rack that you can pull an 8M board out of, I'll buy
it!  Mine's got quite a few vacant spaces on the main board where the RAM
is - is this another form of upgrade or was it for using smaller RAM chips
to give 2M with different PAL's?

> Upside: I applaude the effort and if it works I may be interested in the
upgrade.
>
> Downside: Anybody who wants to do this has a tremendous amount of work
ahead of them probably not worth the effort. You can buy an ESI32 for around
$200.00 and use midi to play the sounds with your Emax II. Then you have the
capability of 32 MB, Emax/Emax II, Akai, and EIIIX library.

Again, they're still quite a bit more than that in the UK...  I'd like an
ESI32 though.  I've played with one in a friend's studio, and it seems a bit
nicer to use than the equivalent Akai.

> Currently I beleive that you can purchase an EmaxII memory upgrade kit
from Mik at Sound Logic and I beleive it has the fabeled upgrade disk needed
to write the EEPROM.
>
Yes, but it needs the daughter board.  Since I have the requisite 44256
DRAM's by the shedload, but do daughterboard, I suppose I'm SOL...

Cheers,
  Gordon.