ARPIE Troubleshooting

OK I built it - so what now? How do I know if its working?

If you wish to run on a PP3 battery: Insert the battery and ensure nothing is connected to the DC input socket.

If you wish to run on a DC suppy: Ensure the supply is a centre-positive 2.1mm barrel with a voltage of between 7 and 24V

Switch on power using the slide switch on the left edge of the lower board. Slide the switch towards the back to switch on.

If all the above tests work, things are looking pretty good! Now we just need to check out the MIDI side of things…

All good? Excellent. The one last test is of the MIDI synch input (the DIN socket below the CLK LED)

If all the above works - congratulate yourself - you just built your own MIDI arpeggiator!

No activity. Power LED (beside the power switch) does not come on

Power LED is on but nothing is working

No blue LEDs on

Individual Blue LED does not come on/comes on dim

Blue LEDs flicker

All Blue LEDs are on brightly all the time and don’t react to changes in menu selection

This can be the surprising effect of a single LED being soldered in the wrong way around. Carefully check all the LEDs are oriented correctly. This might also result if an LED is failing short circuit (but in this case the faulty LED would not light up, so should be easy to locate and replace)

“Unlit” LEDs illuminate dimly/occasionally flicker dimly when they should be off.

(This might get worse if you lick a fingertip and press it to the exposed tips of the pin header to the lower right of the board). This issue showed up with a particular batch of blue LEDs and it took me a while to get to the bottom of it… the LEDs were sometimes illuminating when their low side was “floating”, perhaps due to current leakage through the transistor or other LEDs. The solution is to add an additional pull up resistor between the low side of the LEDs (The STR/strobe pin on the header) and +5V (VCC). img/FlickerFix.JPG shows how I soldered this. A resistor value of 1.5k seemed to resolve the issue. I found the issue before I used this batch of LEDs in kits and I am not aware of anyone noticing the issue with kits containing LEDs from other batches. However if you notice this with your ARPIE, please let me know. The resistor will be added as standard to the PCB design for future kit runs (from Rev4)

Additional Top Board Diagnostics

If the top (control) board is not working correctly, or at all, here are some diagnostics to try and isolate the problem:
* If you press the HOLD button does the HOLD light come on? The HOLD feature and the other 3 red LEDs are wired independently of the shift register IC’s on the back of the control surface PCB. If none of the red LEDs are coming on but the bottom board is healthy then this suggests one of the following (a) The long pin connector is not fitted, soldered, or oriented correctly or pins need cleaning (b) The LEDs are oriented incorrectly (c) There is a break in the ground connection. To test for case (c) use an ohm meter to measure the resistance between the GND pins on the header and the (-) terminal of the battery (make sure there is not a plug in the DC socket since that disconnects the GND side of the battery).
* There should be a low resistance (no more than a couple of ohms) between the GND pins and the battery (-) terminal when the boards are connected together. If there is a very high resistance or open circuit, check for damage between the GND pins and the PCB “ground plane” on both PCBs. * If there is continuity between the pin header and the battery, check between the GND pins and the switch legs to the lower right side of the HOLD button - these should be connected. An open circuit here would isolate the issue to the ground plane on the upper board. Check for PCB damage below the header.
* Here are some tips to check the red LEDs: (a) The HOLD LED should come on when you press the HOLD button (b) The CLK LED should blink when you are using internal synch (c) The RX and TX LEDs should blink when you connect a MIDI keyboard to MIDI IN and play notes
* The blue LEDs and the buttons (other than HOLD) are driven by the two small shift register components on the back of the board. If the blue LEDs are not working, it is difficult to know if the buttons are working or not, but this is important to help us isolate the issue. Here is a test we can do to see if the keyboard is working even when the blue LEDs are not: Assuming the SYNCH LED is blinking, press the SYNCH button once then press the small switch below the first blue LED. This should stop the SYNC LED blinking (as we switch off the internal synch). Repeating the same should start the SYNCH LED blinking again. You can also try changing tempo when the LED is blinking by pressing SYNC then one of the middle LEDs. If these tests work then it suggests (a) The shift registers are OK (b) The problem is with the low side of the blue LEDs, which pass through the STR pin on the header to transistor TR1 on the main board. Check PCB tracks and solder joints, including transistor TR1, Resistor R18, Resistor R11, IC socket connection for IC1.
* Another test you can carefully do is to briefly short the STR pin to the GND pin below it, using the blade of a screwdriver. If all the blue LEDs come on brightly then this suggests the shift registers are working and the issue is either the connector or the base board (do not light the LEDs too long this way since there is no series resistor to limit the current, so the LEDs could possibly be damaged)
* If the above tests fail then the shift registers, or the connections to them, could be damaged. These components are pre-soldered and tested before being placed into kits, so this should be less likely than issues with other components or joints. However it is worth checking that no solder debris has got attached to the legs of the shift register ICs causing shorts, and that no damage (scratches etc) has occurred to the tracks.
* The following shows the layout of the top side of the header pins (lower right corner of control surface) as they are exposed when the boards are connected together
CLK, DAT, KS1, LD1, LD2, LD3, LD4, STR, SW1, KS2
VCC, VCC, GND, GND, GND, GND, GND, GND, UN1, UN2

Device does not receive MIDI notes/external synch

Device does not send MIDI notes

Cannot upload new firmare

##############################################################
atmega328.name=Arduino Duemilanove w/ ATmega328
atmega328.upload.protocol=stk500
atmega328.upload.maximum_size=30720
atmega328.upload.speed=57600
atmega328.bootloader.low_fuses=0xFF
atmega328.bootloader.high_fuses=0xDA
atmega328.bootloader.extended_fuses=0x05
atmega328.bootloader.path=atmega
atmega328.bootloader.file=ATmegaBOOT_168_atmega328.hex
atmega328.bootloader.unlock_bits=0x3F
atmega328.bootloader.lock_bits=0x0F
atmega328.build.mcu=atmega328p
atmega328.build.f_cpu=16000000L
atmega328.build.core=arduino
atmega328.build.variant=standard

In this block, if your setting of atmega328.upload.protocol is set to arduino try changing to stk500. Save the file and restarted the Arduino environment.