Megadrum Problem

[EricSinger]

Hello, I have the synthex kit and in my lcd apears in first row squares and in the second row nothing.

The Midi led never work, the keys doesn't do nothing and the PC and sequencer reconoces the megadrum OK.

When I press the LEFT when I turn on the megadrum doesn't nothing happened.

Nobody knows the problem?

I don't know much for electronic but I think I reprogram the ATMEGA but I don't know to do.

[Synthex]

Hello, I have the synthex kit and in my lcd apears in first row squares and in the second row nothing.

The Midi led never work, the keys doesn't do nothing and the PC and sequencer reconoces the megadrum OK.

When I press the LEFT when I turn on the megadrum doesn't nothing happened.

Nobody knows the problem?

I don't know much for electronic but I think I reprogram the ATMEGA but I don't know to do.

If press the left button does nothing, the Atmega seems to be dropped.
Have you adjusted the contrast of the LCD ?
Have you checked the soldering, the atmega quartz, ... ?
Has It already worked ?

[dmitri]

First, disconnect the LCD. Then I would check this (some suggestions may appear stupid):

1. Make sure all the IC's are set correctly in the sockets, i.e. not turned 180 degrees.
2. Make sure there are no short circuits due to bad soldering.
3. Make sure there are no broken traces on the PCB.
4. Make sure all the wires are properly connected/soldered correctly (except the LCD wires, keep the LCD disconnected for now).
5. Make sure MIDI LED is soldered with correct polarity.

Now, even if after this MIDI LED doesn't light up when you hit a pad or touch pins 37-40 on Atmega32 with something thin and metal, then I would presume that the Atmega32 IC is not programmed.

[Beamtreetaker]

@eric: Does playing notes using your software synthesizer work?

@Synthex: How to check the crystal? Would one need an oscilloscope for that?

[Synthex]

@Synthex: How to check the crystal? Would one need an oscilloscope for that?

Just replace it by the other one, to test ...

[EricSinger]

The driver of megadrum was installed in the PC few days ago without problem.

I think if this possible, the crystal is in perfect condicion, i'm wrong?

[Synthex]

Has It already worked, or never ?

Do you use 20MHz crystal for Atmega ?

[dmitri]

There should be two crystals on Synthex's PCB - one for PIC18F2550 and another for Atmega32. Do you have both?
The thing that PC recognized MegaDrum as USB device only means that PIC18F2550 is working. It doesn't mean everything else is working. In your case Atmega32 appears to be not working.

[EricSinger]

I went to my high school this afternoon and I use an oscilloscope for measure the wave of the 20Mhz crystal and shows a DC +1v. The other crystal seems state OK because the wave is Sinousidal and the frequency is 12Mhz.

Me and my teacher replace the crystal of 20Mhz and happend the same think.

We think the Atmega is death because there aren't a sinousidal wave in crystal and I should replace them for new Atmega. Do you think this or other thing?

Thanks for all for your answer!! and excuse my bad english.

The megadrum NEVER work and my PC detect it because the PIC running OK

[dmitri]

1. What is the voltage on pin 10 of Atmega?
2. What is the voltage on pin 9 of Atmega?

Disconnect MegaDrum from a PC/power.

3. What is the resistance between pin 12 of Atmega and ground?
4. What is the resistance between pin 13 of Atmega and ground?
5. What is the resistance between pins 12 and 13 of Atmega?
6. What are exact markings on C1 and C2 capacitors (which are near the 20MHz crystal)?