[sdiy] Experience with Encore's OBX MIDI kit?

[tprivitera at nc.rr.com]

MC,

Thanks again.  I think that's it.  I see a trace extending from the notch of the Z80, jumpered across 2 pads and then the trace terminates in an empty via right next to IC 118.  Won't be able to re-install the kit until late tonight, but I'm very optimistic now!

BTW, for anyone interested in expanding out your OBX and are tired of waiting years for vintage cards to show up on the market, do not hesitate to get the CrowBX cards.  I have one in my OBX along with 6 original cards and Scott Ryder aka Old Crow totally nailed it.  Oscillators, filters, dead-on. It took some tweaking of the timing parameters of the envelopes and installation of some multi-turn trimmers to dial all the right timings in by ear to match the original cards (took a while), but now that it's set, there isn't any significant difference between the new card and vintage on any of my patches.

Figured I'd share.

Thanks,
Tim


---- Michael E Caloroso <mec.forumreader at gmail.com> wrote: 
> I have an OB-X from the same year as yours.
> 
> There is a "gotcha"... early OB-Xs didn't tie the /reset pin to pin 4
> of A119 (4011), it tied to the junction of the simple (but ineffective
> as they later learned) RC pullup.  Refer to the schematic and you'll
> see jumpers for either option.  The Encore instructions neglect this
> crucial detail.
> 
> On the processor board, look for a trace extending from the
> orientation notch of the Z80 that terminates to a via.  This line goes
> to the /reset pin of the CPU.  I wired the reset wire from the Encore
> board to this via, and it has worked fine ever since.
> 
> MC
> 
> On 5/7/17, rsdio at audiobanshee.com <rsdio at audiobanshee.com> wrote:
> > Hi Tim,
> >
> > Are the installation instructions for the OB-X MIDI kit online and publicly
> > accessible? I have no experience with this kit, but a glance at the
> > installation instructions might give a clue as to what might have gone
> > wrong.
> >
> > It's really good news that re-installing the original chips made everything
> > come back. That means you didn't kill your circuits with static-discharge, a
> > short, or anything extreme like that.
> >
> > Brian
> >
> >
> > On May 7, 2017, at 6:47 PM, <tprivitera at nc.rr.com> wrote:
> >> Anyone have experience installing/troubleshooting Encore's OBX MIDI kit?
> >> I just installed one in my late '79 OBX and when I fired it up, nothing
> >> happens (no lights on any of the control panel, no functionality in
> >> control panel, no sound, absolutely nada - dead Obie).
> >>
> >> It's a pretty straightforward installation pulling the Z80, EPROMs and
> >> memory, then seating the processor on the new board, connecting the ribbon
> >> cable to the old Z80 socket and soldering just 2 wires from the new board
> >> to pins on a 4011.  I'm 100% sure I seated everything correctly and
> >> soldered the wires to the correct pins.  I didn't wire up the MIDI
> >> connectors or punch the holes in the chassis yet, as I wanted to test up
> >> to this point of the install before completing.
> >>
> >> I pulled the kit and re-installed all chips back in their original
> >> positions on the OBX's processor board and everything came back (less my
> >> patches).
> >>
> >> Any gotchas that someone with a similar experience can shed some light
> >> on?
> >>
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> >