Circuit bending: Reverse switch on EMX!

achkasov · Post by **achkasov** » Thu Jul 21, 2011 5:57 am

Hi guys i just checked out what’s under the hood of my EMX1 SD and to add a famous mute switch (i failed at it though :] ). But what have i found was way more interesting: there are unsoldered switch and a led, right above OSC EDIT 1 knob: LED28 and SW21.

I was curious what are they for and found an EMX Service Manual which says LED28 and SW21 stands for “(reverse)”. Yeah, exactly that way in parentheses. Also SW21 doesn’t have four of contact points like the rest buttons, just two. Accroding to scheme four contact points are used just for duplication, to make the device more reliable.

Here are different photos and screenshots of the blueprints:
http://picplz.com/kP8m (AkselPL’s EMX1)
http://picplz.com/kP8g

Anyone to try solder it out?

PS: and this applies to the original EMX1 with SmartMedia too, according to AkselPL’s pictures.

tim from texas · Post by **tim from texas** » Thu Jul 21, 2011 6:35 am

i was going to suggest that the same boards are in the emx as the esx (since the esx has a reverse button) but the location is all off... i looked at your photos and ended up browsing through that page you have your stuff on... you take cool photos! the 8bit/nintendo things made out of the plastic bead iron things are rad!

achkasov · Post by **achkasov** » Thu Jul 21, 2011 6:58 am

EMX and ESX control boards are different, mother board and outboard are almost the same, i believe (except the internal memory chip). And you are right the (reverse) location is off the ESX’s REVERSE actually it is exactly where ESX has ROLL.

Being a sceptic i believe this is an unimplemented feature, because EMX coders were unable to code that feature (mostly due to memory issues, according to Service manual EMX has only 64Mbit=8Mb of memory, while ESX has twice as much). I believe nothing would happen if i am to wire up this button.

offtopic: Thank you for your comment about photos, i am a bit fan of these oldschool 8bit related things.

tim from texas · Post by **tim from texas** » Thu Jul 21, 2011 7:55 am

i am ALWAYS down to see/read/hear whatever oddball things people are doing to/with their gear...

X-Trade · Post by **X-Trade** » Thu Jul 21, 2011 6:09 pm

Sounds like someone has got to try it and see if it does anything. If it was programmed in, it probably only affects the sampled drum waveforms.

Disclaimer: obviously only if you're comfortable with 'circuit bending' your EMX. I can not take responsibility if you try this and your EMX is broken.

Just saying it sounds interesting.

achkasov · Post by **achkasov** » Fri Jul 22, 2011 3:28 pm

I will definitelly try it out.

gil videla · Post by **gil videla** » Fri Jul 22, 2011 3:32 pm

If this works sounds like a neat idea. however, I'm not certain how it would be applied for my needs. "REVERSE" is usually kewl on drum sounds, I don't use the EMX for drum sounds since I have a Machinedrum and the EMX drums suck ass (except for a few hi-hats and 1 kick i like).

so I'd do it only after I heard confirmation from someone who did it first. I have a friend who is a science / electronics teacher in HS does all my soldering needs.

FranzK · Post by **FranzK** » Tue Jul 26, 2011 1:12 pm

I would like a reverse button on EMX. It's one of many things they improved with the ESX! (The other being - the drums have resonant filters on EACH! Which is GREAT - many machines don't have that at all.)

FranzK · Post by **FranzK** » Tue Jul 26, 2011 3:26 pm

Speaking of which -

Has ANYBODY managed to circuit bend the functionality
(not just the controls or lights)
of any electribe units?

And if so - what resulted?

I bet the earlier units would be the best canditates

radiatesky · Post by **radiatesky** » Tue Jul 26, 2011 8:16 pm

http://www.youtube.com/watch?v=nRSIfjh4ryQ&sns=em

This guy has a pitch mod that's sweet.

achkasov · Post by **achkasov** » Wed Aug 03, 2011 3:19 pm

small update:
I just have passed my EMX to a friend who is more familiar with soldering than i do. Also i found another one interesting thing under the hood of EMX: an unsoldered JTAG pins (according to service manual)! JTAG is a port designed to scan memory and state of a processor in realtime; theoretically is is possible to flash the firmware and read it.

So at first we are going to check will the reverse feature work (i presume not, lol). Also i started to read Renesas SH3 processor manual (the one used in ESX and EMX), in the case it will be possible to dump the firmware and disassemble it. I am not very skilled at reverse engineering but if there is a way to tweak a firmware... who knew maybe it will turn out into something interesting.

achkasov · Post by **achkasov** » Tue Aug 09, 2011 9:48 am

So i have soldered it. Nothing works, just as expected.

thenoiseybeast · Post by **thenoiseybeast** » Thu Sep 08, 2011 3:06 pm

radiatesky wrote:http://www.youtube.com/watch?v=nRSIfjh4ryQ&sns=em

This guy has a pitch mod that's sweet.

Hey thanks!!!

sqz · Post by **sqz** » Sun Oct 05, 2014 7:03 pm

any updates on this?

fyi. here's more info: http://tinyurl.com/nd9axr8

sqz · Post by **sqz** » Thu Oct 09, 2014 8:04 pm

Hi Guys,

For anybody interested in reverse engineering, please join in on this 'free the electribe' project:

https://github.com/coderofsalvation/ele ... ngineering