Help Losing reception on my device

[semus]

Hey there,
im using a galaxy s4 gti9505 for about 5 months now,
i bought it refurbished, but i've never had any problems with it.
around a month ago it started losing reception, to the point where i dont get any service 75% of the day..
i had a couple of times where it worked perfectly fine again for 2-3 days in a row, but then it lost reception again.
i was on cyanogenmod, switched to aokp, when that didnt help i switched a provider, which helped for a couple of days.

my next guess is to send my phone for repairs, but i was thinking you guys might suggest something before that?

Thanks alot.

 

[Mr. Lucky]

Are you using a metal phone case? If so, try it without the case and see if the situation improves (depending on design, metal case can block signal). Barring that, then yes, repair or replacement is probably called for.

 

[semus]

Thanks for the tip, but I do not use any case.

But earlier today i used a preasurized air gun to clean my phone and everything works smoothly since... hope it stays this way.