Rockdude discusses precision rectifiers and positional sens

[airflamesred]

Just to confirm, the red wire is no 1. You can get a pair of scissors and cut between the wires and then pull them away to separate them.
In other news, it's my birthday and am waiting for the postman to deliver a midi breath controller! Now, this is going to allow me to control sustain, on e drums.

ps. Sorry for the digression.

[angr77]

Congrats!

Breath controller? I had one to my Yamaha DX7 1985...

Best Regards

ANGR77

[rockdude]

Yep sorry, I meant the 32 input connector... As for the exact wire, I can't be sure looking at that photo with the jacks - it's the ninth wire starting at the top if you were to look at the ribbon cable plugged into the MD main board as shown in the photo above. You're correct about how to connect everything once you have the right wire.

I think I have it located Here's a better picture where I've colored the 9th wire in blue:


Edit. Thanks airflamesred for confirming too.

[ignotus]

Yep, that's the one.

Happy birthday airflamesred!

[rockdude]

Components ordered! Now I'll just have to wait and prepare my megaDRUM for the surgical operation and prepare a nice place for the precision rectifier board in the megaDRUM-case

[rockdude]

.....and four years later I tried making the precision rectifier Without success

I'm not sure what I've done wrong, but probably some components are put in the wrong direction or in the wrong place. I tried to do them like the schematic you drew by hand earlier in this thread Ignotus

This is how it looks when on my precision rectifier board (ugly as f.. I know):
Can anyone see anything that's obviously weird and wrong besides the ugly soldering and wiring by me?

[rockdude]

When I connect the board to my MegaDrum the MegaDrum can't be seen as a midi device by my mac (I wonder why that happens when the precision rectifier is connected) and the display on MegaDrum looks like below with a maxed out input and the MegaDrum led light is constantly on. Can that be a clue to what might be wrong with my precision rectifier board? When I disconnect the precision rectifier my MegaDrum can be found by my computer again.


Here's how it looks when I've connected the precision rectifier board to my MegaDrum:

[ignotus]

I can't see it properly, but it looks like you might have reversed the polarity of the 1uF cap between 5v and gnd. The negative leg goes to ground and is marked on the cap with the vertical stripe.

[rockdude]

I can't see it properly, but it looks like you might have reversed the polarity of the 1uF cap between 5v and gnd. The negative leg goes to ground and is marked on the cap with the vertical stripe.

You were right, I had reversed the polarity. I've put it in the right way now but it didn't make any difference. I should add that if I power up megadrum without the computer on, it starts as normal...but when I turn the computer on, the input gets maxed out and the led is on constantly.
Four years later and you reply like it was yesterday, much appreciated Ignotus, even though I haven't solved the problem yet
Do you see anything else on the board (maybe I need to take better photos)? Could it be an issue with the power and ground from the MegaDrum?
It's only the 1uF and the 1N4148 that I have to worry about which way they are positioned? Or are more of the components on the board sensitive to direction too?

[ignotus]

Sounds strange. Check that you haven't reversed vcc and gnd where you take them from the MD board. Other than that, the electrolytic cap and the diode, there's nothing else with polarity.

Haha, I checked in, saw your post and remembered I'd sent you that chip years ago... I'd rather it served a purpose than go to waste. Maybe someone else has an idea what could be wrong.