Thanks, Jack. And yes, bad RAM will pretty much prevent the unit from running. We used to run program code directly out of flash, but at some point, we exceeded the space on the part so we had to deliver compressed binaries and decompress them into RAM. That's what it's doing when the dots are going across the screen. Good ol' zip...
-Aaron
PS. in case anyone remembers "flashprep", that's what that does -- adds decompression logic to the boot loader so that you could load compressed binaries...
On Nov 27, 2010, at 11:59 PM, Jack Pratt wrote:
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>
> U16 = 54-pin TSOP II (pin side is longer than other side)
>
> From: lovecolour <lovecolour@...>
> To: xl7@yahoogroups.com
> Sent: Sat, November 27, 2010 8:30:53 PM
> Subject: [xl7] Re: MP7 and QROM queries
>
>
> Thanks -- anyway you can tell me which is the ram chip, so I can tell them?!?!?
> Would that prevent new OS from loading? It loads anywhere from 1/10 to 3/5 of the way before failing, but always fails to load completely.
>
> --- In xl7@yahoogroups.com, Aaron Eppolito <synthesis77@...> wrote:
> >
> > You answered your own question! =)
> >
> > >> except sometimes doesn't pass RAM test
> >
> > You have faulty RAM. That's why sometimes random stuff fails. If you're lucky, it could be just the solder joints on the RAM chip. Have someone handy with surface mount parts check & resolder them and you might be all set...
> >
> > -Aaron
> >
> > On Nov 22, 2010, at 3:16 PM, lovecolour wrote:
> >
> > > BTW it has OS 1.31
> > >
> > > --- In xl7@yahoogroups.com, "lovecolour" <lovecolour@> wrote:
> > >>
> > >> Bought a used MP7 with MROM ... after about 2- 3 hours use I got a message ERROR CODE 001 Bad Instruction! Fatal - Just how fatal is it? It goes through all diagnostics well - except sometimes doesn't pass RAM test.
> > >>
> > >> I tried updating to OS 2.00 but it always quits sometime after a couple thousand bytes xferred, sometimes til about 2/3 of the way completed.
> > >> I had to use 2 different midi hookups to go that far (in say a USB Midi and out a parallel port midi)
> > >>
> > >> If repairable (or if I get a new one) will I be able to play back sequences formed on MR 76 with out trouble. I am particularly interested in knowing if the QROM maps the drums (non-GM) the same as the MR/ZR. (I did find out how to record from the drum machine on those boards)
> > >>
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> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
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