Was it a kit with a pre-programmed chip?

Unfortunately, a good way of knowing if the chip is alive is to try talking to it with an AVR programmer. I assume you don’t have one?

The AVR programmer is an USB device to talk to an AVR chip – for reading its memory, or flashing programs onto it. The chip in your kit is programmed ; but to help you identify your problem we need to know if the chip is alive or not ; and to do that, the best way is to try to talk to it with an AVR programmer.

I will make a picture and post it, so you can have a look.
One thing I forgot to mention: I destroyed the encoder by soldering it to the wrong side of the board (don´t ask why i did this!).
I have replaced it with the the following item, to me it is excactly the same as the original one, but maby this is not the case?

http://www.conrad.de/ce/de/product/700708/ENCODER-STEC12E08/SHOP_AREA_17386&promotionareaSearchDetail=005

One thing: if you turn the contrast trimmer to one of its extreme positions, do you get filled squares on the LCD?

Ok… Then it means that the most likely cause of the problem is that the processor just doesn’t boot. Check the soldering of the crystal, check for shorts between adjacent pins of the MCU.

Check the lower pins on the right side of IC2. The third one from the bottom looks a bit funky, maybe it’s just the picture.

How about getting a solder wick in between the display and the CPU and gently trying to remove some of the excess solder?

Some pins could be the same, at least on a very large IC package. You would have to check the data sheet to be sure. However, let’s assume that’s not the case here for this small CPU.

Ouch. The two pins on the bottom left are for the crystal – with them shorted the MCU cannot boot. To confirm – because sometimes it’s hard to probe the tiny pins of the MCU – check that there is no short between the left and right pads of the crystal.

The pins on the top left of the MCU are the LCD enable pin and the MIDI in/out respectively. Shorting them will cause serious problems on both the display and MIDI transmission.

Nope! Just hit it (carefully) with another drop of solder. Don’t overheat it, don’t make a cold solder joint. If that doesn’t help, let’s find the trace where it leads to and carefully solder a thin wire to there.

For repairs try a High Power computer controlled Iron with low temperature, so you can be shure it holds the low temperature no matter what/how long you touch with it. I work at 300° – but i have a rather good 60W Soldering Station….

I think pin 19 an 20 could be shorted as well. You should see my FrankenPal after replacing the whole MCU (the first was dead, still don’t know why) without hot air smd rework tool, there are I wires… With time, a good soldering station, a good wick and good flux one can do amazing things. ;-)

First-thanks to all of you for your help and motivation.
I got a new iron tip, lots of solder wick and flux to fix the shorts at the CPU.
I cleared most of them but remain with a very strange one, see photo.
Strange thing, there must be something behind or under the pins??
Anybody go an idea?

I got the device running for some 30 seconds, but backlight is dead.
Than it crashed again and was dead again.

I doubt very much that I get this thing properly running in the end, anyway thanks for help.

finally-a clear end in the end! smoke signals out of the CPU.
I would say: that was it! we can close the issue.
I think I was not patient enough when I first soldered the CPU-but to be honest, this is not easy.

Any chance to get a new kit without case for reduced price for a second try?

Best regards!

not as bad as in the video!
checked voltage: 3,3 V on the measure points, 9V at power supply.

Probably a good idea to switch to assembled kits. At least for soldering heroes like me!
Please contact me when you are ready to send out the ready made midipals.

Best regards.