[sdiy] OB-Xa unknown MIDI-Interface

[grant musictechnologiesgroup.com]

Possibly a Numera which is a JLC clone?

https://reverb.com/item/45328067-oberheim-ob-xa-midi-interface-archive-sound

https://forum.vintagesynth.com/viewtopic.php?t=69628

GB




------ Original Message ------
From "Florian Anwander" <fanwander at mnet-online.de<mailto:fanwander at mnet-online.de>>
To "AH Heaven" <analogue at hyperreal.org<mailto:analogue at hyperreal.org>>; "*SYNTH DIY" <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>>
Date 5/4/2024 2:02:22 PM
Subject [sdiy] OB-Xa unknown MIDI-Interface

Hello everybody

I'm in the process of restoring my OB-Xa. In manual mode it now works perfectly, but as soon as I edit a sound from memory, all kinds of parameters are no longer correct. I suspect the MIDI interface and the 120 program slot expansion.

This is what the MIDI interface with the SRAM chip looks like:
https://www.florian-anwander.de/oberheim_obxa/OB-Xa-MIDI-interface.JPG
The EPROMs on the control board look like this:
https://www.florian-anwander.de/oberheim_obxa/OB-Xa-MIDI-interface-EPROM.JPG

The memory expansion obviously uses a 6116 SRAM. The original 6514 (IC109 and IC111) have been removed.
I have not found a picture of an identical MIDI interface on the web.


Do any of you know which manufacturer this MIDI interface is from?

Best Regards
Florian

(I've sent the same mail to the oberheim group at groups.io - sorry, if it reaches you twice)

--
http://www.florian-anwander.de/
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