Sphero spiderman - Wifi/bluetooth

[Marcel84]

Hi everyone,

I hope someone can help me further with my repair project. Relatively new to it so its a learning curve for me. I'm trying to repair a spiderman bot made by Sphero. If i turn it on, the music plays (so it does something) but it requires wifi/bluetooth to continue and that is where it stops in the app. It gets stuck as in nothing happens and remains trying to find a signal. Hence my guess was a faulty realtek chip (RTL8723CS which are not easy to find) or the antenna. Replacing the antenna did not work unfortunately.

Sadly, after replacing the chip with a new one the problem also remained the same and just to be sure with yet another chip still the same problem. So i looks like its not the chip or just very unlucky?

What I have noticed and don't understand is the following (see the attachment).

• At A. The pin at the chip at A (the RFIO) is grounded. I measure continuity between that pin and groundpin. I have checked it for shorts (none) and also measured it using another but same chip that is not mounted on the pcb. Just directly on the chip itself and got the same result. Its shorted on the chip itself (by design since multiple chips indicate the same?) but i don't understand it. Is that normal for a RFIO?
• At A. Because the pin (chipside) at A is grounded the capacitor is shorted at both sides. Its a 2.2pf capacitor.
• At B. I think its a kind of coil. Looks like a capacitor but has a bar in it. The datasheet it is mentioned as a coil with value 2n2H. Am I correct to assume that?
• At C. Shorted because of the pin at A. It should be a 1.8pf capacitor.   
• At D. I dont measure ground at either side. Replaced the capacitor with a known working one. Same result. Its a 22pf capacitor. 

If i measure continuity from pin A it only goes to D. Not further. If i measure continuity from the antenna it also stops at D. Replacing the capacitor did not had any affect unfortunately. 

Hence I'm lost. Is it normal that the RFIO is shorted to ground? Has anyone an idea how i can approach this problem further or is it unrepairable?

Hope someone can advice me to try something new or share a new thought.

Regards,

Marcel