[sdiy] EFM MIDI-Gate?

[Chromatest J. Pantsmaker]

I think I may have a dead optocoupler, so I'm gonna buy some
replacements and see if that helps.  I'm not really sure how to check
the one I have.  I'm using the o-scope software (freeware) that uses
your soundcard as an interface.  Pins 5, 6, 7, and 8 all show the same
waveform which doesn't seem right to me at all.

On Fri, Nov 13, 2009 at 7:16 AM, Dave Kendall <davekendall at ntlworld.com> wrote:
> Hi.
>
> FWIW, I stuffed the board years ago, but never tested it. However I made a
> couple of notes when examining the circuit traces.
>
> Silkscreen error:  +5V and GND down near the 7805 voltage regulator are
> incorrectly swapped over. +5V should be nearest the edge of the board.
> It works, but the silkscreen is wrong..... (batch number H&L - 1 5100)
>
> D1 should be jumpered. LED is not used. (don't know why - I think I got that
> from Tom G's notes some time....) The pad nearest to the legend J1 is
> ground, the pad connected to junction of D1 and R1 is +15V or +12V.
>
> C2 is a 10uF electro (25V ). The negative is connected to GND, ie. facing in
> towards R8. (did I sub the ceramic caps? Hmmmm)
>
> I haven't got the board in front of me, so can't check exactly why I wrote
> this stuff.
>
> Hope this helps anyway...
>
> cheers,
> Dave
>
>
>
> On Nov 12, 2009, at 06:08, Chromatest J. Pantsmaker wrote:
>
>> So, I'm starting to revisit some old projects... The first of which is
>> the EFM MIDI-Gate interface.
>>
>> I have one built, but at the time when I built it, I couldn't get it
>> to work.  That was roughly in 2000 or so.
>>
>> I have the original PDF file, but as I remember, there were often
>> extensive re-work notes for each EFM board produced.
>>
>> Does anybody have those notes?
>>
>> Does anybody have a working MIDI-gate who could help me troubleshoot mine?
>>
>> --
>> .sig
>> -Chromatest J. Pantsmaker
>> http://www.chromatest.net
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>
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-- 
.sig
-Chromatest J. Pantsmaker
http://www.chromatest.net