first time poster here. I'm seeking advice on how to fix my melzi boards. I have 2 melzi 2.0_v5 boards from a 3d printer that I'm trying to fix. I'll try to give as much info as i could.
Melzi 1 -- can upload bootloader but cant upload sketches. I can upload the repetier firmware directly via usbasp clone and it runs standalone. Firmware hangs when PC connects to it. It also hangs when I press the reset button it becomes unresponsive. Need to power cycle to get it to work again. I can print via sd card though. Used to work with the same firmware but after some time the LCD becomes all white. Reflashing the same firmware restores it back to working condition until this happens.
Melzi 2 -- comes in with firmware for a different printer, cant upload sketch so I figured I flash a bootloader. failed during bootloader flash. cannot upload anymore
avrdude: set SCK frequency to 93750 Hz
avrdude: warning: cannot set sck period. please check for usbasp firmware update.
avrdude: error: program enable: target doesn't answer. 1
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.
Any advise on what to do to fix board #1?
Can I use the ISP with external clock method to fix board #2? Do I need to desolder the chip from the board or can I just connect to xtal1 and use the icsp?
I only have a multimeter, Uno, mega2560, usbasp and hot air soldering station to use. No oscilloscope
Any wiring diagrams I should follow is greatly appreciated.
I attached the picture of the board. Both boards are identical
It would be nice to get these boards running normally again.. Thank you in advance.
Thanks for clearly pointing out what MCU is that – that really helps to help You....
I will assume it's 328p...
Melzi 1 – it looks like 328p is fine in this one, I think it's problem with FTDI circuit. If You use external FTDI it will probably work fine.
Melzi 2 – specify Your method of flashing bootloader.
Please go where there is more light and take close up pictures of connectors and MCU, write all silkscreen next to connectors pins, link those board manufacturer page – do some work damit...
Your first 2 links doesn't wok.
You did not write out silkscreen.
Leave those poor MCUs alone, they're fine.
sampinon:
The MCU is 1284p for both boards. Both uses CH340G instead of FTDI.
they do same task.
If it works with SD card (SPI) that means MCU is fine, it's problem with serial to USB communication – CH340G chip purpose. Find TX and RX pins, connect external CH340G "FTDI" to them and try to communicate thru it with board via PC as usual. If it works – my theory confirmed.