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I tested my megadrum(V2.8) a while ago with out LCD and buttons and just connected it by usb to my pc and my pc would immediately recognize it as a megadrum. After that i wanted to test one of my edrums on it so i connected one jack to the pcb and tried it but it didnt worked i also installed the megadrum config tool and tried to get it working which didnt happen only got a tripping crash cymble sound out of it so i pulled out the usb cable.

Now i do have the lcd connected and the buttons but my pc's doesnt recognize it anymore when i connect it to my pc. Also the lcd doesnt show anything but black blocks and does not react on the buttons. What could i have messed up in my earlier attempt to test it and is there a way to reset it?

First, you have to read this: http://www.megadrum.info/forums/viewtopic.php?f=3&t=492

I have rad it and will check it tommorow when a friend comes by with a multimeter.

But my main concern is that windows doesnt recognize the megadrum anymore and that I messed up something with the megadrum config tool or something. Is that possible?

Tested it both on my laptop with vista and my pc with xp

Crazyanz wrote:I have rad it and will check it tommorow when a friend comes by with a multimeter.

But my main concern is that windows doesnt recognize the megadrum anymore

One problem at a time.

and that I messed up something with the megadrum config tool or something. Is that possible?

No, it is not possible.

If you don't use my version of PIC18F2550 firmware and didn't make a modification to your board as advised in http://www.megadrum.info/forums/viewtopic.php?f=3&t=268 I won't be able to help with the USB problem. You can read more about this in http://www.megadrum.info/forums/viewtopic.php?f=3&t=790

so first fix the lcd and then the USB problem?

Crazyanz wrote:so first fix the lcd and then the USB problem?

Doesn't matter in what order.

i just found out i already had a multimeter so this is what i came up with:

there is 5V on pin 1-2 and 0,61 on 1-3 strangest thing is while trying some things at one moment I had the top row with all black blocks. I couldnt adjust them though so i powered it off and on again then the screen was empty again and I couldnt get back to the black blocks. Then while measuring some voltages the screen for 1 second showed all the text just readable :S I tried to redo the same action but it didnt happen twice

After going trough the complete lcd guide i couldnt really find the problem only thing I can come up with is that my atmega crystal is wrong. This brings me to another question I used a 16mhz crystal but the V2.8 pcb says 16 or 20mhz I also have a 20mhz crystal here. Would that make any difference if I replaced the 16mhz with a 20mhz one?

Crazyanz wrote:i just found out i already had a multimeter so this is what i came up with:

there is 5V on pin 1-2 and 0,61 on 1-3 strangest thing is while trying some things at one moment I had the top row with all black blocks. I couldnt adjust them though so i powered it off and on again then the screen was empty again and I couldnt get back to the black blocks. Then while measuring some voltages the screen for 1 second showed all the text just readable :S I tried to redo the same action but it didnt happen twice

You have a classic case of a bad/loose contact/wiring/soldering.

After going trough the complete lcd guide i couldnt really find the problem only thing I can come up with is that my atmega crystal is wrong. This brings me to another question I used a 16mhz crystal but the V2.8 pcb says 16 or 20mhz I also have a 20mhz crystal here. Would that make any difference if I replaced the 16mhz with a 20mhz one?

For Atmega32 it should be 16MHz crystal.

i checked all the soldering and it looks all fine to me? Im no pro at soldering so i could be wrong but when everything is soldered properly into place what can be loose or have bad contact?

Crazyanz wrote:i checked all the soldering and it looks all fine to me? Im no pro at soldering so i could be wrong but when everything is soldered properly into place what can be loose or have bad contact?

Wires, connectors' sockets, ICs' sockets - anything with mechanical contacts.