Messages

1

preenfm2 and preenfm3 / Re: Help with new build - OLED not working

« on: September 16, 2020, 03:31:35 AM »

Hi,

I ordered and installed a new OLED display and the unit is now working fine.  So, it appears that the OLED itself was the issue.  I can only explain it by something I did when jumpering the two pins with the R5d resistor in place must have damaged the OLED somehow.

The spec sheet I was referring to was for the New Haven Display: https://www.mouser.com/datasheet/2/291/NHD-0420DZW-AB5-247046.pdf.

Thanks for your patience troubleshooting my problem.  Thanks also for creating and supporting the PreenFM.  I'm looking forward to playing with it.

2

preenfm2 and preenfm3 / Re: Help with new build - OLED not working

« on: September 10, 2020, 02:49:22 AM »

Hi,

Thank you - this helps.  I get continuity between all of the points in the schema OLED-DIP40. 

I noticed that by putting the jumper in, I was feeding the 4.6V from pin 2 to 15.  It's labeled 'no connect' in the spec sheet, but could that have an effect?

3

preenfm2 and preenfm3 / Re: Help with new build - OLED not working

« on: September 09, 2020, 03:32:13 AM »

Sadly, I see the same behavior in bootloader mode.  I see the bootloader screen for less than a second and then it goes blank. 

I was wondering if it would help to flash the STM32F405 the hard way again? Or, do you think it could be something is wrong with the gpio itself?

I did check continuity between the PreenF405 and the display pins.  Numbering the display from left to right 1-16 and the DIP40 socket from left to right 1-20 top (t) and bottom (b) in the last image I uploaded, I see the following:

display / preen
pin 1 - pin 19 (b)
pin 5 - pin 19 (b)
pin 7 - pin 19 (b)
pin 8 - pin 19 (b)
pin 9 - pin 19 (b)
pin 10 - pin 19 (b)
pin 11 - pin 8 (t)
pin 12 - pin 9 (t)
pin 13 - pin 10 (t)
pin 14 - pin 11 (t)

4

preenfm2 and preenfm3 / Re: Help with new build - OLED not working

« on: September 08, 2020, 02:20:40 AM »

Hi,

Thanks - appreciate the help where to focus.  Attached is a photo of the PreenF405 DIP40 socket.  What pins on the PreenF405 should I check for continuity against which pins on the OLED?

Is there any chance the PreenF405 is corrupted somehow or would need to be reflashed?

5

preenfm2 and preenfm3 / Re: Help with new build - OLED not working

« on: September 07, 2020, 12:03:22 AM »

Here's the back of the board.  I had difficulty with attachments on the first post.  Thanks again.

6

preenfm2 and preenfm3 / Help with new build - OLED not working

« on: September 07, 2020, 12:01:29 AM »

Hi,

I'm having trouble getting my PreenFM2 up and running.  It's a kit from Van Daal Electronics that I built over the weekend.

I followed all of the instructions, including the Yellow OLED high frequency solution (http://ixox.fr/forum/index.php?topic=69159.0), clipping the pin and adding the jumper. I added the 22 Ohm resistor at the spot in the upper right of the board indicated.  Unfortunately, I didn't realize I had the R5d version of the board.

When I started it for the first time, the OLED display flickered, was dim in places and there was high frequency noise.  But, I could navigate the menus, generate random patches, and play notes via MIDI.  The encoders, volume, and LEDs were all functional.

I thought no problem, I'll remove the accidental fix and I should be set.  I desoldered the jumper and replaced the clipped pin.  But then the loading screen would appear briefly (<1 sec) and then go blank.  By pressing the MENU button, I could get something to appear. The display did not flicker, but the text was completely garbled. 

I've checked all of the points in the troubleshooting thread (http://ixox.fr/forum/index.php?topic=63509.0) and the values are all the same, with the exception of the marked display pin, which is 4.6V. (Pin 4 is 3.3V). 

I thought it might be an issue with either the header on the board or the OLED.  I delsoldered and replaced the header on the board.  I desoldered/resoldered the header on the OLED.  There didn't appear to be a short between adjacent pins.

I tried to reflash via bootloader, but the behavior is the same, which makes it difficult to navigate.  The bootloader screen appears for <1 sec and disappears to a blank screen.

Any thoughts what might be happening or what else I could try to solve the problem?  For the few minutes I had it up and running, it was nice.  I'm looking forward to spending more time playing with it.

Thanks in advance for your help.