Vintage Synth Repair

--- In vintagesynthrepair@yahoogroups.com, "Roy J. Tellason" 
<rtellason@...> wrote:
>
> On Monday 21 April 2008 10:47, oxygeno1313 wrote:
> > You can't just replace the CPU 8049 with another 8049, you need 
get
> > it from roland if still available or from other 101 working CPU.
> >
> > The fact is that the CPU it's programmed, it has an internal ROM.
> > the same processor as Polysix, Juno 60 and other synthesizers.
> 
> I was wondering how long it was going to take before somebody 
brought this 
> up. :-)
> 
> > The other option is to take a working CPU and copy the information
> > with a burner capable to read and write 8049 and buy a new 8049 or
> > 8749.
> 
> Nope.
> 
> > The difference between 8049 and 8749 is that the first one you 
> > can program it just one time and you can't erase the information.
> 
> That's incorrect.  Those are not "One-time Programmable (aka OTP) 
devices,  
> they're mask-programmed,  which means that this gets done at the 
factory 
> where the chip is made.  Which means that they're only practical 
for high 
> volume applications.
> 
> > The 8749 it's the same version as 8049 but it has a EPROM, that 
you
> > can erase it with a UV Eraser.
> 
> Yup,  but I'm not sure that you can take one and just drop it into 
a socket 
> that's intended for an 8049 and have everything else work with no 
changes. A 
> detailed examination of the datasheets might answer that one...
> 
> 
> -- 
> Member of the toughest, meanest, deadliest, most unrelenting -- and
> ablest -- form of life in this section of space,  a critter that can
> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet 
Masters"
> -
> Information is more dangerous than cannon to a society ruled by 
lies. --James 
> M Dakin
>

Well, the D80C49Cs have not arrived yet but I´ll try them anyway.
Something funny should happen.