Technical questions for the MPC2000xl and the MPC2000
By musiccankill Thu Aug 02, 2012 3:02 pm
Hello!
I just got an mpc2000xl..!
It has a zip drive but i changed it for a floppy cause i dont have any zips right now...
The problem seems too strange to me...
There is no ram installed inside..
When i try to record anything it says in the length "0.00 sec" and i cannot change it..
Also the are no record button on the screen as it should(F6 if i remember right)...
It shows only reset peak....
When i go to the load screen it says that there are 65388kb ram free :S and when i try to load anything (even if its 4 kb) it says not enough memory..
The same thing is going on even if i install ram sticks on the sockets (tried several i have on other samplers and are working great)...
Always it shows 65388kb free sample memory...
It loads sequences ok but not sounds...
Any ideas what is going on?
Thanks in advance...!
By musiccankill Thu Aug 02, 2012 3:09 pm
No!
Even if it does that!it shouldnt say 65 megs (it natively supports up to 32 dont know how the hell does it say 65 megs free sound memory)...!!
And as i am loading from floppy ,one floppy isn't enough to fill all the memory at startup!!
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By Lampdog Thu Aug 02, 2012 3:56 pm
Take out the memory and boot up again.

Default mem on the motherboard should take over and and read 2mb.
re-install your memory again, if it reads 65mb again, maybe the slots are dirty/ corroded. maybe the memory is unseated. maybe the Memory is bad.
By musiccankill Thu Aug 02, 2012 4:03 pm
hello! Thanks for the reply..
As i say in the vid description, there was no memory inside,just the bare motherboard...
Also checked with the hidden menu (shift+5 , shift+f1) and with the open windows in the record screen and there in both it says 0mwords...
Whats going on?
Tried both with and withoud memory sticks inside...
By musiccankill Fri Aug 03, 2012 12:30 am
Checked everything and seems to be working ok (resistors,capacitors,resistor ladders and every single component..)
Also i tried to remove the IC250(dram (from what i saw in the schematic thats the sound ram)) and the problem is the same...
0mwords installed no matter what size of ram i have installed during tha test...
Still saying 65388 in the free sound memory in the save/load menu...
Any other ideas what to check?
Also i have a question...
Is it possible to be just the dram chip i have already out?
Also i saw that the big dsp ic , which is akai's custom chip,has direct access to the database...
Thanks again..!
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By mr_debauch Fri Aug 03, 2012 4:27 am
Well.. maybe reinstall the OS..

also, try disconnecting that floppy drive you put in there... try sampling in the sample screen.. maybe something is causing a conflict.
By musiccankill Fri Aug 03, 2012 7:30 am
Hello!
Thanks for the reply..!
Just tried both 1.14 and 1.2 os and still the same...Tried both with the internal ZIP (IDE) and floppy and without anything and still the same...
I am starting to think that its the custom dsp controller...
I will try to find a replacement ram if i can to put it in the place of the old i removed in case it needs it to work...
If you have any other ideas please tell me!
The thing that makes me wonder whats going on is that the sequencer is working fine (loading, saving ,recording midi data)...
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By mr_debauch Fri Aug 03, 2012 3:10 pm
I dont know... it's just an odd problem I have never heard of before.

Im sure you tried disconnecting every component, connector and ribbon cable already... and re-seating them..... right? I always suggest this even though it does look like a failure with the hardware.... just to rule out potential conflicts. Sometimes weird stuff happens like that.

maybe take a tooth brush and alcohol and clear the PCB with the on board ram. make sure there are no cracks in the traces? It doesn't sound like the mpc is using the on board ram though.. make sure the simm connectors are clean and so is the area around it...


other than that I have no idea besides snagging a burned screen 2000xl on the cheap or a motherboard.
By musiccankill Fri Aug 03, 2012 3:34 pm
mr_debauch wrote:I dont know... it's just an odd problem I have never heard of before.

Im sure you tried disconnecting every component, connector and ribbon cable already... and re-seating them..... right? I always suggest this even though it does look like a failure with the hardware.... just to rule out potential conflicts. Sometimes weird stuff happens like that.

maybe take a tooth brush and alcohol and clear the PCB with the on board ram. make sure there are no cracks in the traces? It doesn't sound like the mpc is using the on board ram though.. make sure the simm connectors are clean and so is the area around it...


other than that I have no idea besides snagging a burned screen 2000xl on the cheap or a motherboard.

Hello..!
Tried everything...
I removed the board and resoldered the simm connectors to be sure they are ok also reflowed the custom dsp chip but that didnt worked too...
I haven't checked with multimeter all the traces yet but there is no visible damage on any of them (at least near the ram area)...
If i cannot find a ram chip to buy so to replace the one which may be faulty and i have already removed from the motherboard i will swap it with another one on the motherboard to see if this will work or at least if it will change anything...
I am almost sure that there is a fault with the custom dsp chip cause it sees 0mb ram in the recording section (so it knnows that there is no ram inside) but for some reason it says 65388 in the free snd memory on the loading screen...
At least i can still use it as a sequencer with another sampler...

Does anybody know if a working 2kxl will work without the onboard 2mb (16mbit) ram chip but with 32mb expansion ram in simms?
I am not sure it will because i dont know what part decides about which ram will be used if there are 32mb installed..!
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By Lampdog Fri Aug 03, 2012 3:39 pm
Any amount of memory in the slots will override the motherboard 2mb.
Meaning the onboard 2mb will not be used when ram is in the slots.
By musiccankill Fri Aug 03, 2012 3:48 pm
I remember from my old (and working) 2kxl that if you have under 32 megs , then onboard ram works and is added to the stick you used...
The schematics make me think the same too but i dont have a working unit right now to test it so i cant be sure for that...
I also dont know if it needs the 2mb onboard ram installed in order to see the simms..!
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By mr_debauch Fri Aug 03, 2012 3:55 pm
musiccankill wrote:I remember from my old (and working) 2kxl that if you have under 32 megs , then onboard ram works and is added to the stick you used...
The schematics make me think the same too but i dont have a working unit right now to test it so i cant be sure for that...
I also dont know if it needs the 2mb onboard ram installed in order to see the simms..!



I dont know if it needs the 2 megs to see the simms either... but yes, it maxes out at 32 megs, however if you install 16 megs instead it shows 18 megs.

I dont know if the sequence memory comes from the 2 megs onboard.