Thx for tip on CMD resistor. Replaced it and now everything works, currently dumping emmc.
Replacing it weren't that bad. With a microscope and some flux it went pretty fast. First time doing 0201 though.
MM I actually soldered one side of the resistor to a lab board to be able to measure it better, if I measured it on the underside I got a 4.8k reading sometimes but not when putting probes on the sides or top. So my guess is that I perhaps burnt...
Thx,
tried reflowing the resistor with hot air but still 1.1M ohm.
WIll have to find some 0201 4.7k ohm resistors somewhere.
I guess 0201 is not so bad but this one sits in an awkward spot.
EDIT: removed resistor from board and meassured I...
Ah ok, it's a 0201 size?
It gets tinier and tinier :)
May I ask the reason why it needs to be replaced?
What is the supposed stock value? I meassured it inline and get 1.1M Ohm
Replaced dat0 resistor to 133 ohm.
Tested to boot into OFW but get purple screen, I guess I should replace 47 ohm CMD resistor aswell then.
Hard to replace resistors on this chip they are so tiny and sit so close to each other :)
Well it makes more sense if the resistor is burnt, usually we get "slow emmc" when resistance is low, that's why we started using 100ohm instead of 47ohm which was used originally and if yours is damaged you might be getting 0ohms.
Both rp2040...
Get 47 ohm readings on the other resistors. Only dat0(C point) resitor which is no reading. Does not look burnt so my guess it was like this from factory.
Ordering a few 0402 100 ohms resistor.
Can I just disconnect rp2040 chip to boot to ofw...
Thx didn't know.
I remembered incorrectly I did this mod on a switch lite to train soldering and that one had 250ohm when I measured. (On that board it actually worked.)
Measured on this OLED board and actually seems that the resistor is broken...
So was happy getting splash screen on my OLED but that turned sour pretty quickly when going to backup emmc.
Anyone have any idea what could be the problem?
Could it be "ribbon" cable below emmc? Although I got good diode reading.
I belive emmc...