Help request for troubleshouting Preen fm

[Henk vd Broek]

Last weekend i tried build my Preen fm ,and now  i have some problems with my build
and like to have some help with  troubleshouting it
my problem is that my display stays black so i don,t know were to start
I installed the windows driver so the  microcontroller is working
but that,s all i can tell about it
I hope someone can help me with my problem

[Xavier]

Hi,

Of course we can help 

First check : the jumpers.
Jmp1 & Jm2 must be ON.
Jmp3 must be OFF.

Then check this thread :
http://ixox.fr/forum/index.php?topic=63470.0
I posted a picture with some point you can check voltage.

Then if no success, post some good quality pictures of the 2 sides of your PCB.

Thanks,

Xavier

[Henk vd Broek]

I found the picture ,and measured the points
and it seems that i don,t have 2,5v on pin 16 of both i,c,s
and i can,t measure anything on the resistor 2,5v points
any ideas???

[Henk vd Broek]

another picture of my build

[funkyfli]

What values do you have at those points?  Are they shorted to ground?

[Xavier]

2.5v points are set by the DAC when received relative 0 from the CERB40 board.
Which means, if you don't have 2.5v, your CERB40 is not working or not flashed.
Did you flash your CERB40 correctly ?
http://ixox.fr/preenfm2/build-it/burn-firmware/


Xavier

[Henk vd Broek]

i checked the bootloader   and reinstalled it  using Zadig
but my dislplay stays black ,not even a blink of a led 
 my multimeter says that there is no shortcut to the ground from the 2,5v v points

[Xavier]

First check : the jumpers.
Jmp1 & Jmp2 must be ON.
Jmp3 must be OFF.

Please double check and confirm this.
JMP3 must be open... Seems like i see some soldering near the 2 pins.

Xavier

[Henk vd Broek]

good evening  Xavier ,
still nothing and no jumper problems
i did some reading this afternoon on ghielectrics.com ,and if i read it right
the only thing the m.c normally needs to start is the 3.3 v  v.r 
isn,t it ??

[funkyfli]

If you are getting 3.3 volts at pin 1 and not 2.5 volts at the correct points then the odds are your cerb40 either does not have the preenfm firmware installed or it is in the DFU / Firmware update mode.  This matches with your blank screen.  Jumper 3 does look like it is 'bridged' which would cause the DFU mode - I'd triple check that one .  Also, pins 6 and 7 on the cerb40 look like they might? be bridged which may or may not have any effect...

[Henk vd Broek]

i think my controller isn,t working as is shout be
because i can flash it but nothing on my display no error message ,nothing
the only idea i have is trying another m.c. ,but thats a bit expensive
the only one i could find with the fez cer40 is mouser 25 euro +25 euro shipping
but i found this one for 12 euro

http://www.bitsandparts.eu/showarticles_info/0001STM32F103C8T6_BOARD/1-2/STM32_ARM_development_board_STM32F103C8T6_.html
can you tell me if this one fits in the Preenfm

[Xavier]

I've never seen any not working CERB40 untill now.
I don't know where you bought yours.

The URL you copied is not a CERB40 at all... Doesn't even have the same MCU.
It won't work.

Jumper 3 does look like it is 'bridged' which would cause the DFU mode - I'd triple check that one .

Agreed.... Please check with a multimeter. Or please post a closer picture of JMP3.

Xavier

[Henk vd Broek]

Hi there, it,s me again

 jumper 3 has no shortcut (i checked it with the multimeter)
I installed the bootloader again ,and device manager is recognize  the m.c saying everything is working properly
 so it,s probably not the m.c
then i remove  jumper 3  and power it again
but still no sign of life
it,s making me a bit crazy ,don,t knowing  how to figure it out
I don,t want to sound more stupid than i feel ,but i was thinking
What if i measure the voltages at the pins of the m.c ??
can you do something with that ? check if something is wrong   

[Xavier]

I installed the bootloader again ,and device manager is recognize  the m.c saying everything is working properly

You installed both bootlader AND firmware, right ?
What if you press a key when switching the preenfm2 on ? Does the leds light up ?

It can be a bad soldering point:
. that prevents the CERB40 from runing.
. that prevent the CERB40 from sending any info to the DAC. 
. an OLED problem.
Or a mixture of the aboce.

Does your preenfm make sound ? A small "plop" when you switch it on ? Play sound when you send midi ?
I cannot read the DAC model you have... double check  it's a MCP 4922.