RPM gauge not working
 

My classic sti RPM gauge/tacho is not working properly, i put white dials in and since then the needle starts at 5000rpm and only works above that. ive changed the rpm unit a couple of times but still doesnt work properly

what can i do, id rather not touch it myself because of the headache ive had while trying to fit the speedo converter/dials etc

i live in east london, any recommendations? please?