GEKLÄRT targets not recognized, please HELP

[Nuvolari]

Good morning to the Community!

I have a problem with one of my Racers which isn't able to see the gymkhana targets. Since I'm new of assembly/disassembly I prefer to ask your instructions before to break something 🙄

BTW I think I see the IR light (through the smartphone camera). 

I read something about the "spring" but before to proceed buying a new one, I would like to check a little bit better:
1) I was thinking to change the spring with another Racer which correctly see the targets and check, but how can I remove it? Should I loosen the screw of the spring until it comes out? Other?
2) If it's still not working (so not a spring issue) may I try to change the "whole rotating system" from a Racer to another? The purpose is to understand which part is not working.
3) Is it possible to change the "whole rotating system" from a Classic to a D1 too? Are they identical or anything is different in the contacts which touch the electronic card?

Any help is greatly appreciated 🙂 

Kind regards,
Nuv

EDIT: I have found to way to remove the spring and unfortunately this is NOT the problem, because it doesn't work also with another spring.
It looks if I change the "whole central unit" (taken from another Racer) it works, so I fear something is damaged in there... 😞 

[MFB29]

As always: check it for dust.

[Nuvolari]

Hi and thank you for reply 🙂 

I fixed it in these couple of days, in the case it may help someone else, the problem (the Racer was reading only the Finish, not any other target) was:
- not the dust
- not the spring
- but "probably" the firmware --> it was already up to date but I received this used car like this, don't know exactly how, but repeating the firmware update fixed it (there is a long post in the DR!FT Community in Facebook about).

Greetings,
Nuv