Possible Faults On Handset; Mobile Unit Faulty Due To Humidity - Siemens Gigaset 4010 Micro Service Manual

5.1.6 Possible faults on handset

5.1.6.1 Mobile unit faulty due to humidity

Note: Most humidity damages on the front side under the keypad. Look at all
electronic components on the back side.
Remaining flux on the component side could look similar to a humidity damage
(white deposits) but it will disappear when heating it up with a hot air blower.
Recommendation:
When you are not sure whether deposit is humidity or flux, heat the area concerned
with a hot air blower and scrap the unit only when deposit doesn't disappear.
The pictures below are taken from G2000 and 3000 handsets.
Humidity
--> scrap
R
Scrap
No scrap
Flux