[FIXED] pfm2 Eurorack : DIY help, frozen screen

[zmberber]

I just finished building my preenfm2.  I have the Eurorack version by Van Daal Electronics, but I do still hope you can help me with my problems.  See here https://vandaal-electronics.com/product/preenfm-eurorack-module-diy-kit/

Btw I have read the FAQ.

When I first turned on the module, I got the greeting screen, I got to the edit screen or something (i don't remember, but it looked like in the videos etc), and then it froze, and then it said "!STM32F4 USB DFU!" on the screen.

Whenever I reboot, I usually get a fully lit screen.  So I tried booting up again while holding a button to open the boot menu.  That works fine, but as soon as I boot or something, it starts freezing.  I reformatted the stick and copied the pfm2 folder onto it again, but still it is no better.  I also tried flashing the firmware etc, I still get either a blank fully lit screen, or when I do get to the normal edit menu etc it freezes.

Does someone know what could be wrong?  what should I try doing?  I do think I paid attention that all the soldering was done correctly, but should I check every soldering point again?  Can I do some measurements somewhere?  I hope you can help.

[Xavier]

Hi,

It's a bit confusing.

"!STM32F4 USB DFU!" is only reachable from the bootloader. And it's normal it's frozen at this point, the MCU is waiting to be update through USB (DFU mode).

If the preenfm2 is frozen on a fully lit screen, it's very often a problem with the USB key.
Did you keep the "pfm2/" folder on the key ? It must be there.

Do you have another USB key to try (after copying the pfm2 folder on it) ?

[zmberber]

Ok then I guess I have it wrong in memory, or it glitched, I thought that once it suddenly got from the normal preenfm2 edit mode to the USB DFU screen.

I copied the pfm2 folder to my computer, formatted the stick (vfat), and then i copied it to the root directory again.  same behaviour.

i have other usb sticks, but they all have way over 4GB.  Does that make a difference?

Thanks for the help!

[Xavier]

i have other usb sticks, but they all have way over 4GB.  Does that make a difference?

No i have some 32Gb key working fine.
http://ixox.fr/preenfm2/preenfm/usb-drive/

So you can give them a try.

[zmberber]

Okay, I tried with multiple sticks.  one was a 128 GB, and one was a 4GB.

I got the following behaviour:  The 128GB didn't work at all, just like before (btw the stick I used before was actually 64 GB).  I tried the 4GB stick.  It booted, I was able to do stuff in edit mode for a few seconds, and then it suddenly froze.  And then, as soon as I rebooted, it gave me the fully lit blank screen again.  And this happens over and over everytime I reboot.  think if I wait for a longer time and I power on the module again, I can get to the edit menu again for a few seconds, but then it will freeze again (Or maybe I am just imagining stuff).  Could it be that some capacitor is wrong or faulty?  Is my USB reader broken or something?

Btw thanks again for your quick responses and thanks for your engaged help!

[Xavier]

It booted, I was able to do stuff in edit mode for a few seconds, and then it suddenly froze.  And then, as soon as I rebooted, it gave me the fully lit blank screen again.  And this happens over and over everytime I reboot.  think if I wait for a longer time and I power on the module again, I can get to the edit menu again for a few seconds, but then it will freeze again (Or maybe I am just imagining stuff).  Could it be that some capacitor is wrong or faulty?  Is my USB reader broken or something?

When you say "it suddenly froze", is it when you access browse or load presets ? or at any moment ?

Could it be that some capacitor is wrong or faulty?  Is my USB reader broken or something?

No i don't think so (for both question).
That's weird.
Could be a bad connection of the preenf405. Double check the DIP40 soldering and push a little more the preenf405 inside.

Ardi from Van Daal Electronics follows this forum, but you can try to contact him directly to see if he has an idea.

[zmberber]

I just think posting stuff in the forum is good because others might have similar problems so they can see how I fix my problems (that's what forums are for, right? ).


= = = = = = =
Xavier EDITED : Sorry i made a bad action with this message and remove 80% of it 
But i totally agree with what you wrote 

[zmberber]

Hm, I pressed on the chip, and then I was able to play around in edit mode a bit longer than before, but then as soon as I pressed "menu", it froze and then I saw the blank screen again.

I tried again, I wiggled around the chip (i put it in and out of the socket), tried again, but this time, i hardly did anything, and then it froze.

i am not sure if pressing "menu" was the reason, i think it was just random.

EDIT: yes indeed, it is random, i again had the situation that i got a blank screen just suddenly (i scrolled through algos).  it really seems to be random, because this time it happened after i did nothing.

EDIT 2:  And this time, I did the following: It booted, I was able to do stuff, then I did nothing, then I waited, and then I just tapped the module (the whole thing, I just tapped the chassis), and then it gave me the blank screen.  So apparently there is some faulty connection of the (or a) chip.

[Xavier]

EDIT 2:  And this time, I did the following: It booted, I was able to do stuff, then I did nothing, then I waited, and then I just tapped the module (the whole thing, I just tapped the chassis), and then it gave me the blank screen.  So apparently there is some faulty connection of the (or a) chip.

That could explain.

Just in case : there's a display problem with 2.20beta firmware when screensaver is activated.
Mais sure that's not what you have.... Stick with 2.12_cv version for the eurorack for the moment.

[zmberber]

i have p2_cv_2.12.bin, so that should be the correct version.

so apparently i need to check out the chip...  damnit... maybe i should check the soldering points of the socket for the chip?  or i should desolder and solder a new socket??  i hope i can work it out...

[lokki]

i would definitely start by just reheating all the preenf405 socket connections. remove the preenf405 first then reheat all the connections on the sockets, make sure they make good clean solder blops. do you have a multimeter?

did you solder the preenf405 headers on your own? this would be my next guess for failure.

[served]

Hello.

Preenf405 is assembled by me and tested and run and confimed to be working.
I hand soldered the Pinstrips. You can have a look at it, but I am sure they look good, as I am very strict on the soldering quality.
So I would think its something else. Look over the 20pin sockets where the preenf405 is sitting.
Look over the USB Drive connector, make sure there is no excess stress on it.

The USB stick with that patch is not cheap chineese crap that brakes. So I am sure that the stick is good.
The stick has been formated from 64GB to 1GB and FAT32 so that PreenFM can read it.
Dont change it.

Is your 5V coming from your eurorack bus or from the onboard regulator?

Remove the screen and make visual inspection on all solder points. Make sure there are no shorts.

[zmberber]

i would definitely start by just reheating all the preenf405 socket connections. remove the preenf405 first then reheat all the connections on the sockets, make sure they make good clean solder blops. do you have a multimeter?

yes i have a multimeter.  i thought i did have clean solder blops, i thought i paid attention but i will do as you say and try that.

did you solder the preenf405 headers on your own? this would be my next guess for failure.

no i didn't, the headers were presoldered by van daal electronics.  i don't know if they test it there (solder headers, then check with a socket of a working module etc EDIT: yes they do, see message by served).  but i did think about that too.

[zmberber]

Look over the USB Drive connector, make sure there is no excess stress on it.

It is angled slightly upwards, as you suggested in your instructions, and you are right, it won't fit otherwise.  What do you mean by stress?  It seems like the connectors are soldered well, and the drive connector is stable, but I can still check that.

The stick has been formated from 64GB to 1GB and FAT32 so that PreenFM can read it.
Dont change it.

Hm... I didn't change the partitioning, I just reformated the (only existent) partition itself (vfat) and copied the pfm2 folder onto the root directory again.  So there should be no problems there.  Also, it did read the stick, it just froze again.

Is your 5V coming from your eurorack bus or from the onboard regulator?

The 5V is coming from the Eurorack bus, which I selected via the jumper.

[served]

Great!

Remove all the IC-s from the sockets.
Keep the preenf405 and USB stick in place and try to boot. See what happens.