Finished build, no boot [Solved]

[Eamoex]

Hi Everyone,

just finished my PreenFM2 build (kit bought from VanDaal) and it doesn't boot. I power it from USB. I populated jumpers 1 and 2. USB stick has all files on it.

I did things I'm not sure I should have done:

• put the OLED 22 Ohm resistor (I still don't understand the difference between "OLED" and "OLED Mod"...)
• put a 10K variable resistor in the reserved slot just because I thought it would be cool to be able to dim the screen

Symptoms:

• Preen doesn't register in Win10x64 when connected
• USB stick LED lights up continuous
• LD33CV reg warms up
• LM7805 reg stays cool
• screen remains pitch black
• PCB LEDs won't blink whatever knob I twiddle or switch I push

Any help appreciated!

[Xavier]

Hi,

You can start by reading this thread :
http://ixox.fr/forum/index.php?topic=63509.0
And verify the different points shown of message #6.

[Xavier]

And to answer your questions.

.  Yellow oled screen do need this 22 Ohm resistor, specially if you add an aluminium shield.
. I don't think it's usefull anymore with blue Oled.

. the 10k variable resistor is used by LCD screen to adjust the contrast. It's useless on OLED.

[Eamoex]

Thanks Xavier. I am out right now so I'll make the checks tonight. Just a few more questions before that:

.  Yellow oled screen do need this 22 Ohm resistor, specially if you add an aluminium shield.

This still means I should short these two contacts with a wire or zero Ohm resistor, right?

. the 10k variable resistor is used by LCD screen to adjust the contrast. It's useless on OLED.

Okay. It doesn't matter if I leave the variable resistor there, does it?

And finally: I know which leg is the anode on LEDs, but suppose I soldered them the wrong way, could it be that much of a show stopper?

[Xavier]

.  Yellow oled screen do need this 22 Ohm resistor, specially if you add an aluminium shield.

This still means I should short these two contacts with a wire or zero Ohm resistor, right?

Yes it must be shorted !
0 ohm or 22 ohm but shorted...

You can leave the varaibale resistor, no problem. It's just not used.

Leds wrongly wired does not have any impact on the rest. They just won't light up.

[Eamoex]

Thanks for your help Xavier. I found the problem. The problem is that I'm a moron. LD33CV was mounted the wrong way around... 

The screen is blue and it does look strange. Pixel horizontal lines change intensity individually, relatively fast, giving a shimmering effect. If there's few information on the screen, the shimmering stops, but lines still have various intensities. Weird. Being clueless, I tried to short the 22 Ohm resistor to see if it stopped this behavior, but it doesn't change anything.

EDIT: as per instructions, I have left one of the 68 Ohm resistors unpopulated (the one next to the 10μH inductor). Should I put something here?

[Eamoex]

Okay, shorted the 22 Ohm resistor for good now with a soldered beefy cable and screen is steady. Attached images from my build, showing double shield (grounded sheet from VanDaal + 128-layer aluminium foil taped "cushion", snugged under it).

All working fine. Can't wait to test this bad boy at the jam on Friday!

[Xavier]

All working fine. Can't wait to test this bad boy at the jam on Friday!

Cool 
Thanks for the update !