Modify EXM-002 memory board?

Has anyone tried modifying a EXM-002 to operate as EXM-008?

From first glance at the pictures, the logic seems to be the same but I thought I would make a post here asking insight from others before potentially ruining a memory board.

i'm pretty sure its not possible to mod a 2mb board into an 8mb board. you'd have to do lots of dead bug wiring, and the wires would probably end up causing interference problems.

the memory boards aren't exactly complicated, it would probably be totally possible to clone them. unfortunaly it would require a bit more time and patience than i have at the moment.

it'd only take one person to clone the board design and start selling blank pcbs, and we'd all be happy!

i currently only have 2mb in my s1000 which is actualy more than enough until i start loading things from sample cds, then it gets small pretty quickly.

i wonder how hard those connectors are to find?

@motosega from the pictures I've seen of the 8mb board, the layout looks pretty identical. I was thinking that what could work is simply switching the surface mount ram to a higher denomination but I wanted to touch base with some other people here to see what experience or thoughts they had on the matter.

As for your S1000, I believe I have seen a board made by an Australian, the website escapes me right now but it was designed to utilize a normal 32mb simm but he wants like $500aud for it which is ridiculous.

I know what you mean about filling up the ram quickly, I have 10mb on my S1000 and after a few sample patches from the akai cds you can forget about doing anything on the machine!

motosega wrote:it'd only take one person to clone the board design and start selling blank pcbs, and we'd all be happy!

So you can rock it like this?




If someone wants to send me detailed photo of the front side, rear side, connector, and images of the chips where they are readable, I'll take a crack at it.

And this is taking a lucky swing. If there are traces that run through the center of the board, I obviously won't be able to see where they go. From some not so great photos tho, it looked totally traceable. So yeah. Defiantly worth a shot trying to draw it up in Eagle CAD to see what I can come up with.

Close up of all components I mean to add. Like resistors so we can know the band colors, and the values of the capacitor (will say on the side!)

motosega wrote:i wonder how hard those connectors are to find?

They look like pretty standard headers




EDIT:

motosega wrote:the memory boards aren't exactly complicated, it would probably be totally possible to clone them. unfortunaly it would require a bit more time and patience than i have at the moment.

I just noticed you said have knowledge in this area also, then I'm sure you can fill any blanks I run into!

Star One: i'll take my ram card out and make a load of high res photos in the next few days.
it's only a 2mb card but i suppose we have to start somewhere.

i have some skills in this area, but i'm no expert, i've designed and made single sided pcbs before but nothing complex, just simple microcontroller projects like dmx lighting controllers and other theatrical effects stuff. i can certainly double check your work.

if i remember correctly, it's a 3 layer card, a card like this would have to be made at a pcb fab house.

if there are some traces that you can't see it'll still be possible to work out where they are supposed to go. the ram chips are standard parts and the datasheets are available online.

my advice would be to make a straight clone of the card, using through-hole components and following the traces on the board exactly as they are. i've no idea how things like capacitance and RF interference start happening at high frequencies on boards like this so its as well just making a straight clone to avoid having to think about it.

richie: if the cards are identical but just have diferent sized chips on them then yes, its totaly doable, just by switch the ram chips, but from the cards i've seen it seem like they are diferent pcbs.

the 32mb cards from first principles are a bit more complex, they have a programable logic chip on them, the akai and mutec cards just have a bit of 74x logic. if i could get 8mb in my S1000 without going broke i'd be happy.

@motosega Yeah I was thinking the same thing however before potentially damaging a board, I thought I would touch base with some of you folks here. Thanks for responding in that regard.

Also, maybe it may be advisable to look at the Mutec boards for the S1000/S1000 as the layout of their boards seems much more easier to diagnose than the more crammed Akai issued memory?

By the way - these are the boards I was talking about which do utilize custom logic:

http://www.firstpr.com.au/rwi/smem/

I am not advocating for cloning this fellas design, I'd gladly pay for one but not for 2-3 times the cost of getting an actual sampler, jeez.

the mutec boards are smd. the best board to clone would be one of the akai boards with through hole components, that way we don't need to get into smd reflow. anybody can solder a through hole board with a 15€ soldering iron.

probably the first thing to do would be collect high rez photos of as many ram boards as possible the look for the easiest one to clone with the highest capacity.

we can probably manage an 8mb board, definatly 4mb

the 8mb boards in star one's photo use sil chips, whereas my 2mb board uses dip chips which are easier to find.

cloning the first principles boards, apart from being rude, would mean cloning the programable logic chip. which i don't think is within our collective ability. being able to use a standard sim is great though.

what boards do you guys have in your samplers?

@motosega - personally, I've drag soldered smaller ic's with smaller points and more legs than that several times, so it's not an issue for me. My guess is you're looking for a simpler solution, a kit if you will, that anyone could slap together with minimal chance of screwing up?

I have no idea what you are referring to in relation to being rude and principals board though.

I've attached some macro shots as well:

https://www.dropbox.com/s/vaygl34k97nouha/s1000-8mb%20top.jpg?dl=0
https://www.dropbox.com/s/zxcx80dhwvjdvw4/s1000-8mb%20bottom.jpg?dl=0
https://www.dropbox.com/s/yamoagtwa2alqjs/s1000-8mb%20bottom%20alternate.jpg?dl=0
https://www.dropbox.com/s/2tyt0yndnu5ixhf/s1000-2mb%20top.jpg?dl=0
https://www.dropbox.com/s/gtgfyjtxt86ilsu/s1000-2mb%20bottom.jpg?dl=0

Enjoy.

Transcribed directly from the S1100 repair manual.

EXM-008:
16x HM51400ZP-10
2x CD74AC541E
2x HD74HC541P
1x 64P-6033-0431-0 64P, Just a normal DIN 41612 connector.

The memory from my S1000 8mb board differs:
16x Fujitsu MB814100-80P
4x CD74AC541E
1x 64P-6033-0431-0 64P

I can't quite tell the values of the resistors as they're in package format. I'll have to open the machine again later and try to get a closer look.

The board with 1MB (I thought it was 2MB, my mistake) memory isn't really as interesting in my opinion, as it is la lesser amount of memory but I'll have to have a look again and document the bands on the resistors.

@star one - There are many other options than the 2 listed for memory. It's just regular fast page memory from what I recall.

Are you asking me if I can measure the board as in the physical measurements or are you still talking about the resistors?

As for the 1mb board, maybe it would be interesting to have one made and socketed just for reference to see what other memory options are available to work with that boards logic.

that's great work guys, i'm totaly convinced this is going in the right direction.

some thoughts:

the dram chips might not end up being cheap or easy to get hold of. however once you have worked out how the chips are connected it wouldn't be a big deal to have two 30 pin simm slots instead, 30 pin simms are easy to find.

Star One: are you making a circuit diagram or going straight to pcb layout? the 2mb board is much easier to understand, and i would imagine that the 8mb board is pretty much identical apart from the number of address lines, a good circuit diagram would make your work much easier.

the address and data lines are most probalby laid out just like a simm module, that should help working out where the hard to see traces are. here is a pdf with the circuit diargam of a 4mb 30 pin simm.
http://www.datasheetarchive.com/dl/Scan ... 035374.pdf

ritchie: i'm not afraid of hand soldering smd chip either, but it would be really cool if pretty much any S1000 owner with a soldering iron could make themself an 8mb card. not so much a kit as a pcb for the masses.

this is really nice stuff guys.

richie wrote:Are you asking me if I can measure the board as in the physical measurements or are you still talking about the resistors?

The measurement of the board. This way it can be the same size. Otherwise the size could come out in every different way then is wanted

motosega wrote:the dram chips might not end up being cheap or easy to get hold of. however once you have worked out how the chips are connected it wouldn't be a big deal to have two 30 pin simm slots instead, 30 pin simms are easy to find.

If someone knows how to do that, that would be cool. I've got no idea how that would work though sadly

And yeah one of the chips is easy to get, the CD74AC541E. The MB814100-80P if Jortin.com actually has it available for purchase. So might end up having to find equivalents

motosega wrote:Star One: are you making a circuit diagram or going straight to pcb layout? the 2mb board is much easier to understand, and i would imagine that the 8mb board is pretty much identical apart from the number of address lines, a good circuit diagram would make your work much easier.

Just doing the board. If someone wants to do a schematic that would be awesome. But trying to make a schematic out of looking at the board would be way outside my area right now.



I love the idea of doing it as a kit. Post the board files, you can download them, upload to OSH park and get yourself 3 of them for pretty cheap. I doubt 3 boards would cost more then 50 bucks. The SMD stuff isin't so bad to do.


And if someone doesn't do soldering, they can have someone who can do it, throw them some cash to build it for em.


Eagle CAD is awesome by the way




Got librarys for all components, so everything will fit properly.




(I'm going to shrink those wires down, don't worry)


The parts I'm having an insanely difficult time following is where the traces go onto the connector. How some skip over to the rear row. Getting pretty lost there. The rest of it I can see pretty well. Might need a close up of those traces and top row of IC's

I don't have an S1000 or S1100, never used one either. Otherwise I wouldn't pester you so much for photos!


EDIT:

If anyone can make a schematic, yes this would fly in terms of how long it will take.

BOOM!


schematics for the exm005 and exm008

https://imgur.com/a/shL9w