wrote:
That is not the question though, the question is - is there standard
software for a PC that would let me test all or most of these
controllers ?

I know a guy that did MIDI music many years ago (late 90s, early 2000s).
I *think* he used software from Cakewalk but I am not 100% sure on this.
They still exist and have several software offerings; I'm not sure which
one you need. (He's not around for me to ask.)

For your purpose, you might want something like a MIDI protocol analzyer,
rather than just a "music" program. A music program will just draw the
sheet music as you play the keyboard; a protocol analzyer will show you
the individual "note on", "note off", etc messages. Some of the music
programs may have a "view MIDI" mode where you can see the raw data.

If you have to check something right *now*, stick a scope on it. I
think it's pins 2 and 4 - either side of the center pin. Should be
31.25 or 31.5 kHz, and IIRC, you'll get activity when you depress a key
and activity when you release it, but I don't think you get anything
when it's just sitting there.

MIDI is unidirectional. If you want a music keyboard to talk to the PC
*and* want the PC to talk to the music keyboard, you need to hook up
two cables. That's why the ports are labeled IN and OUT. Also, the
spec says that the interface is driven by an optocoupler.

I don't know about everyone else but I think if I fix a keyboard I
should test all the keys. Right ?

I think that's probably a good idea.

Also, let's say an older one comes in with the old joystick plug.

You won't see a keyboard with a 15-pin D connector. As far as I know
the standard is/was a 5 pin, 180 degree DIN connector - the "original"
ones that are about 0.6" diameter, not the "mini-DIN" ones that are
about 0.3" diameter.

Back in the day, soundcards that supported MIDI on the joystick port
came with a short adapter cable: one 15 pin D connector to two 5 pin
DIN connectors - one in, one out.

I'm pretty sure you can get a MIDI adapter to go from USB to 5-pin DIN.

Maybe I could make an extender for that joystick jack. With USB it is
no problem, in fact I think I have a USB extension cord.

You can still probably get 5-pin DIN MIDI extensions. Or make some; it
might help to use twisted pair but for short distances you may not have
to.

It seems that audio of some type is what I am going to do now.

Free advice: One thing I have noticed, at least with musicians that play
live, is that a lot of them will patch something up that will work for
two hours. Like, if one of the wires in their amp power cord gets cut,
they'll just strip the ends with a pocket knife and twist them together.
No tape or wire nut or anything. Or, if the input jack on an amp is
flaky, they'll go through all their patch cords until they find one with
an 0.255" plug that works better in that particular jack. It may be
helpful for you, or the person that takes the stuff in at the counter,
to ask about things like that.

Actually another thing might be a power soak.

Many years ago, I recall reading a story, maybe here, that a tech made
one out of an electric stove element. He had it set up so he could
still set a pot of water on the element while he was running an amp.
He had some of his customers convinced that boiling the water with Pink
Floyd made tastier coffee, vs using other music.

At any rate, the MIDI thing is one I know very little about, the
interface and all that.

The Wiki article is OK for a start. http://en.wikipedia.org/wiki/MIDI

I remember some articles on it in Radio-Electronics back in the 80s
when it first got popular; if you have back issues you might take a
look.

Another thing is I intend to connect something other than a guitar to
these amps.

Phil Allison recently posted about his ideal audio generator for testing
this kind of stuff.

Matt Roberds