Yupieru MVT-7100 keys locked

[L3pbru]

I am unable to use any of the direct input keys. The key lock switch makes no difference whether up or down. Pwr/Vol,Squelch,Lamp,Moni all work. I have changed the batteries and pressed the reset button but still unable to use the keys.
Any help much appreciated.
Pete

 

[L3pbru]

Keys locked

Problem solved following advice from JC at Javiation UK. Required removing 8 case screws & 6 on circuit board so that all keys and contact points could be cleaned.