[sdiy] Alesis Midiverb eprom images

[Tony Kalomiris]

Hi Robin,

Thanks so much for this , I really appreciate it.
One question can I can append the FEX to the VERB and burn into a 27C256 as per the original eprom ?
The images you so generously provided are 16 K each.
Could the MVERBFEX be from a MIDIFEX unit and not a MIDIVERB ? Apparently the only difference was one eprom - the hardware was identical.
In fact there was a guy from Ontario who offered a mod that had one half VERB and one half FEX programs, for the best of both worlds.
I know 1986 is a long time ago ;- )

I hate to sound greedy here but you wouldn't happen to also have the 2764 eprom image for the 80C31 ? 
I'm still worried I might have damaged that one , but I doubt it, it's a NMOS part - but you never know.


Tony Kalomiris


On 2010-11-01, at 4:50 AM, Robin Whittle wrote:

> Hi Tony,
> 
> Here are the raw binary images of the EPROM which drives the DSP
> section, for the MIDIVerb in its two incarnations - a reverb device
> and an effects device (delay etc. if I recall correctly):
> 
>  http://www.firstpr.com.au/temp/MIDIVERB/MVERBREV
>  http://www.firstpr.com.au/temp/MIDIVERB/MVERBFEX
> 
> I took these and used them in the mid-80s, but haven't used them
> since.  It is possible to make a dual mode device, with a toggleswitch
> to select between two EPROMs, or to control the highest address bit of
> a 27C512.
> 
> I think the MIDIVerb DSP section is remarkable - just an EPROM,
> standard logic chips, RAM and a DAC, with a bit of analogue circuitry.
> It performs A to D, stereo D to A and then all the effects.  I recall
> staring at the circuit for a long time and still not being able to
> figure out how it works.
> 
>  Cheers
> 
>    - Robin         http://www.firstpr.com.au/rwi/dfish/
> 
>> Hi list,
>> 
>> I think I messed up the 27C256, U51, eprom when I read it in my trusty old eprom programmer.
>> I discovered that to my horror it wasn't properly seated in it's ISA slot.
>> I looked at the bins and could see only a partial read was succesful, i.e. lower 512 are all FF's.
>> Now the unit behaves erratically and distorts and overloads.
>> I also read the 2764 operating system, and it also partially read.
>> I took the normal static precautions and used a ground strap.
>> 
>> I am devastated and am pleading with anybody who might have a copy of the images they'd be willing to share.
>> I can trade for some other machines eprom images.
>> 
>> This is the original 12 bit DAC/SAR Midiverb.
>> 
>> U51 27C256 label reads "MVOBJ 2-6-86" ( effects programs)
>> U54 2764 label reads "MVOP 4-7-86" (operating system for the 80C31)
>> 
>> Appreciate any help with this, in the meantime I have contacted Alesis in a last ditch effort.
>> 
>> Tony Kalomiris
>