Following on from HDs comments:
I do not have the expertise to diagnose the exact reason for intermittent loss of reception, however I do know that when it happens, slight pressure on the base of the aerial fixes it. I tend to use a BNC connected to external aerial so there is no movement of the set thus it behaves perfectly. It seems to happen when the long straight aerial is connected and it puts a bit of sideways pressure on the connector. Better brains than I will probably diagnose this...
I did manage to open up the set to modify the circuitry to use the lock button as a backlight on/off, which involved a little soldering and adding wires etc, amazingly it worked even though I am ham fisted. I did run some solder onto aerial internal connector which seemed to fix the reception for a while, but it probably worked loose again.
As for the set it is very clean and no wear on keyboard which is what Mike was asking for originally. Apart from the intermittent reception problem it is excellent. Hope this is helpful.