The missing pin is for when the Midi board is installed, the NMIb
connection is no longer required from pin 6 of ic42.
Craig
On Wed, 2 Jun 2021, 04:05 FreeLists Mailing List Manager, <
ecartis@xxxxxxxxxxxxx> wrote:
oscar-synth-owners Digest Tue, 01 Jun 2021 Volume: 02 Issue:
050
In This Issue:
[oscar-synth-owners] OSCar Microchip Issue
[oscar-synth-owners] Re: OSCar Microchip Issue
[oscar-synth-owners] Re: OSCar Microchip Issue
----------------------------------------------------------------------
Subject: [oscar-synth-owners] OSCar Microchip Issue
From: Paul Underwood <paulu1055@xxxxxxxxx>
Date: Tue, 1 Jun 2021 22:59:19 +0100
Hey Guys,
Got a few things fixed and appreciate your feedback and help regarding
the old OSCar.
Noticed I have a bit of an issue with a microchip having a pin missing.
specifically 74LS04N 8431 chip on the PCB as seen in the pictures below.
If any one can give me advice on how to fix it please contact me. Many
thanks
https://ibb.co/kxHNQWR
https://ibb.co/VCqBFjk
------------------------------
Subject: [oscar-synth-owners] Re: OSCar Microchip Issue
From: Huebner Informationselektronik <mail@xxxxxxxxxxxx>
Date: Wed, 2 Jun 2021 00:01:03 +0200
A deliberate modification to enable the MIDI daugther board. Nothing to
"fix" here.
Am 01.06.2021 um 23:59 schrieb Paul Underwood:
--
Hey Guys,
Got a few things fixed and appreciate your feedback and help regarding
the old OSCar.
Noticed I have a bit of an issue with a microchip having a pin missing.
specifically 74LS04N 8431 chip on the PCB as seen in the pictures below.
If any one can give me advice on how to fix it please contact me. Many
thanks
https://ibb.co/kxHNQWR
https://ibb.co/VCqBFjk
Mit freundlichen Gruessen / with kind regards
Stefan Huebner
Huebner Informationselektronik
Inh.: Dipl.-Ing. Stefan Huebner
Waidmannstrasse 12e / Haus 5
22769 Hamburg
Germany
tel +49 (40) 89 69 87 69
------------------------------
Date: Tue, 01 Jun 2021 18:41:43 -0400
From: "Bob Grieb" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender
"rlgrieb1"
Subject: [oscar-synth-owners] Re: OSCar Microchip Issue
That pin was holding Z80 NMI high on the original (pre-MIDI)
OScar.=C2=A0 The original OSCar MIDI boards connected all Z80 pins on the
MIDI board to the socket on the lower board, and NMI is used
for MIDI, so that pin had to be either bent out of the socket or cut.
Many boards have it bent out of the socket.=C2=A0=C2=A0 My MIDI board does
not connect that pin on the lower board to anything,
so there is no issue.
You can leave it as it is.
BTW, that is IC42.=C2=A0 8431 is a date code.=C2=A0=C2=A0 31st week of =
1984.
It's when the chip was made.
Bob Grieb
On 6/1/2021 6:01 PM, Huebner Informationselektronik wrote:
A deliberate modification to enable the MIDI daugther board. Nothing to
"fix"here.
Am 01.06.2021 um 23:59 schrieb Paul Underwood:
Hey Guys,
Got a few things fixed and appreciate your feedback and help regarding the
old OSCar. Noticed I have a bit of an issue with a microchip having a pin
missing.
specifically 74LS04N 8431 chip on the PCB as seen in the pictures below.
If any one can give me advice on how to fix it please contact me. Many
thanks
https://ibb.co/kxHNQWR[1]
https://ibb.co/VCqBFjk[2]
=C2= =A0 -- Mit freundlichen Gruessen / with kind regards Stefan Huebner
Huebner Informationselektronik Inh.: Dipl.-Ing. Stefan Huebner
Waidmannstrasse 12e / Haus 5 22769 Hamburg Germany tel +49 (40) 89 69 87
69
[IMG][3]Virus-= free. www.avast.com[4] [5]
--- Links ---
1 3D"https://ibb.co/kxHNQWR=
2 3D"https://ibb.co/VCqBFjk=
3 3D"https://ww=
4 3D"https://www.avast.com/sig-email?utm_medium=3Demail&utm_sou=
5 3D"#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"
------------------------------
End of oscar-synth-owners Digest V2 #50
***************************************
