I would like to collect here some information posted in other threads wich was very useful when I encountered some problems.
As I said before, my knowledge about electronics is reduced to soldering, so I decided to order the kit from Synthex.
Here you can see a picture of all the components I used to build the megadrum.
I started soldering the smaller components: resistors, capacitors, diodes, etc.
Then I added the sockets for the ICs and connectors.
I had to make sure that I soldered all the resistors in the correct place. The pcb by Synthex is already marked with the correct value, however I had to use an online resistors calculator to double check the colors and values. By doing this I had no mistakes done.
It is very useful to follow the pictures provided by Synthex, so you know exactly where the components are placed:
When I had the pcb finished, I continued with the rest of components.
For the keyboard I followed the schematics provided.
For the lcd I had to build first the cable. Synthex provided the connector and I used an old ide cable, I cut a strip of sixteen cables and then they were soldered on the lcd. Just identify pin 1 on your lcd and connector, and the rest are in order. When I first plugged the megadrum my computer dectected it properly, the midi led flashed. However, the screen showed nothing. Then I discovered the use of the trimpot. We can adjust contrast with this trimpot. I read in another thread that this trimpot must be truned clockwise at leas 30 times, and you mus hear a click. I did it, at least 50 times and I heard no click. Then I decided to turn it the other way. And it worked. All the characters were shown correctly, however there seemed to be a problem with the backlight, it was very subdued. Synthex told me to replace the 470 ohms resistor for one of 100 or less value. I did it and the back light increased more.
One of the components was a jumper. I had no idea of its use. Well, the thing is that you have three options:
- Using the jumper in USB Power Switch. By doing this anytime you plug the usb connector the megadrum turns on.
- Using the jumper in Alim Ext Jumper. By doing this you need another source for power.
- Not using the jumper and adding a switch to the USB Power Switch. I have this done. You have a switch which turns on and off the module when connected to your computer via usb.
Please, note that you can't use two jumpers at the same time, one in USB Power Switch and other in USB Power Switch!
Although you have all the information in this forum concerning the building of the megadrum, it isn't organized correctly, so you have to read and re-read every thread to find what you are looking for. As a result, you miss some facts. For instance, I thought that the usb connection was the source for power and for future updates, and that we needed the midi connectors for the "sounds". However, I discovered soon that we send them via usb, so we don't need midi connectors at all. Fortunately, I discovered beforehand that we don't need the ISP and ICSP cables, so I haven't added them.
Finally, the worst part of the job was to identify and solder all the different cables to the jacks. I used again an old ide cable. Pins 1,2, 21, 22, 39,40 are ground, so I soldered all the sleeves to them. Then you have to follow the pinouts provided by Synthex, taking into account that when it says Bow, we solder to the tip, and Edge to the ring:
7 - Hihat Bow --- Tip
8 - Hihat Edge --- Ring
9 - Snare Head --- Tip
10 - Snare Rim --- Ring
and so on
For the pedal jack is exactly the same.
3 - Power source for Hihat controller --- Tip
4 - Hihat controller input --- Ring
And finally, I used the box of a TDT receiver I had at home. The final look isn't very professional but the thing is that it works. As you can see I have to cover the logo by Sanyo
I hope you find this thread useful.
