Emax

My understanding is that the RAM expansion board has PALs that go with it.
Getting the PAL binaries for the SCSI update wasn't easy for Rob at Emulator
Archive.
Even if you duplicated the PCB, you would have to be able to make the PALs
that allow the access to the extra memory.
You would need the original PAL binaries for that.....

Otherwise the Emax wouldn't be able to address the additional memory....
even if it was physically installed.

Someone correct me if I am wrong in my understanding of what was discussed
previous on the thread.

Regards,
Ted




On Mon, Nov 30, 2009 at 1:17 PM, thenewyorkcowboy <
thenewyorkcowboy@...> wrote:

>
>
> Ah, thanks Tristan, now I understand. I was a bit lost on what a 4 bit word
> size meant.
>
> As for acquiring a RAM expansion board, isn't that the holy grail of Emax
> II ownership? Or having enough money in the bank at the very moment someone
> out there wants to sell their 8mb unit outright?
>
> No one yet has found the hidden cache of leftover expansion boards and EMU
> has never been helpful about their production vs. sales figures, if there
> are even enough to think that someday someone will run into the warehouse
> that holds the remaining kits...
>
> Between the member here that just purchased the service manual with
> schematics, and the various PC board prototype manufacturers, shouldn't
> there be a way to at least get the PCB re-made? I have seen companies that
> charge a one time $50 setup, and then have no minimum order requirements.
>
> Another idea if the schematic allows it would be to solder in the 18 pin
> sockets, and then piggyback another one or two 18 pin sockets for height and
> then a 20 pin socket over top of it and simply connect the last two pins in
> the right way through wire-wrap or other means. All the traces that end up
> at the two blue connectors for the expansion board go through all of the 18
> pin holes on their way back to the processor. That of course is a big IF the
> first 18 pins match up on a 20 pin IC which could be determined quickly
> either just by following the traces with the mainboard pulled or with the
> Samsung datasheet and a continuity meter...I know...desperately
> scatterbrained but I like impossible challenges.
>
> --- In emax@yahoogroups.com <emax%40yahoogroups.com>, tu@... wrote:
> >
> > Each of the Samsung chips is 256k x 4 bits. So two of them give you 256kB
> and 8 x 256kB = 2MB.
> >
> > The 18 pin sockets are for the 4464 DRAM used in the 1MB version of the
> Emax II and you cannot use them at the same time as the 20 pin sockets, its
> > either one set of DRAMs or the other. If you want to expand your Emax II
> to more than 2MB you will need to get the RAM expansion board...
> >
> > /Tristan
> >
> > Monday, November 30, 2009, 7:59:55 AM, you wrote:
> >
> > >
> >
> > So I opened up the cover again and did some thorough examination.
> >
> > I have 16 chips of Samsung KM44C256CP-7 up through IC socket 63. At 256k
> per chip I don't initially understand why that only equals 2MB of
> > memory...
> >
> > Sockets 64-99 are available for soldering, but they are 18 pin slots
> compared to the 20 pin Samsungs! What is up with that?
> >
> > I shone a light onto the PC board and it seems all of the traces on two
> sides of the processor go through the respective chip sockets all the way to
> the
> > two expansion board connectors, so that is hopeful that once it can be
> figured out, we can make our own expansion boards right on the mainboard.
> >
> > If we can find the right source for 18 pin IC sockets and the right 44256
> memory modules (70ns,20ns,130ns) I should be able to upgrade my Emax to
> > 6mb of memory right on the mainboard.
> >
> > --- In emax@yahoogroups.com <emax%40yahoogroups.com>, "thenewyorkcowboy"
> <thenewyorkcowboy@> wrote:
> > >
> > > Ah! I finally figured it out. I did more research and my model, the
> 2212 is only a 2mb which I verified by Master 4,Y,2, and got 1048488. Here I
> had
> > been doing improper math but with the Emax II Diagnostics.pdf I came to
> this conclusion. Bad for me! But now I need to find someone that has a late
> > model 2205 with 8mb and find out if the factory installed all the memory
> on the mainboard or did they also use two 2208 kits to get to 8mb. That
> would
> > provide the solution whether or not the mainboard slots could be
> populated with sockets and chips.
>
> > >
> > > --- In emax@yahoogroups.com <emax%40yahoogroups.com>, "Everett"
> <evy_newt@> wrote:
> > > >
> > > > My expanded EMAX actually only has a portion of the sockets filled on
> the main board. I believe the writeup on emulator archive goes through why
> > in more detail. I believe someone else stated that the PALs are different
> on the models with the board installed. The upgrade kit inventory shows
> these
> > PAL chips in there, so that makes sense.
> > > >
> > > > --- In emax@yahoogroups.com <emax%40yahoogroups.com>,
> "thenewyorkcowboy" <thenewyorkcowboy@> wrote:
> > > > >
> > > > > Yeah I was all hopeful until I opened my Emax II up and saw that I
> don't have the board, just an empty space where it looks like there are
> > enough places to solder in sockets to get the Emax II up to 12 megs. I
> have 4 already (16 chips) and there are 32 spaces available. Does anyone
> think
> > that actually soldering in another 16 sockets would be the same as adding
> an expansion board?
>
> > > > >
> > > > > --- In emax@yahoogroups.com <emax%40yahoogroups.com>, Ted Summers
> <djtbs1@> wrote:
> > > > > >
> > > > > > I believe what the Memory Upgrade people are saying is:
> > > > > >
> > > > > > 1) If you have "scrambled megs" and your emax 2 doesn't see all
> your
> > > > > > memory, then they have a fix
> > > > > > 2) If you have a expansion board, and it is not full, you now
> have an
> > > > > > inexpensive way to fill it up the rest of the way and get a chip
> so
> > > > > > emax2 sees the added memory now.
> > > > > >
> > > > > > But I don't think they are saying they are duplicating the
> Expansion
> > > > > > board at all.... you must already have an expansion board.
> > > > > >
> > > > > >
> > > > > >
> > > > > > On Nov 26, 2009, at 6:36 PM, Reinaldo wrote:
> > > > > >
> > > > > > So...
> > > > > >
> > > > > > I can download the file and burn a new eprom chip for my emax II.
> > > > > >
> > > > > > Then I can buy the memory chips on eBay.
> > > > > >
> > > > > > But I need the expansion board!
> > > > > >
> > > > > > How do I do without expansion board then?
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > [Non-text portions of this message have been removed]
> > > > > >
> > > > >
> > > >
> > >
> >
>
>  
>


[Non-text portions of this message have been removed]