Sony CMT-CP11 Hi Fi
Review:
This little set was installed in our kitchen. The speakers were installed above the kitchen cabinets, covered in cling-film to protect them from the grease and dust which collects up there - this did not seem to affect their performance. We bought a Sony as a previous Hi Fi is still running fine after more than 20 years.
Plus side: the audio quality is excellent; the FM tuner is excellent (isn't ANALOGUE wonderful!).
Minus side: it does not switch on immediately, preferring to display an irritating welcome message first (Share & Enjoy!). It loses all its channel settings after a few days disconnected from the mains. The remote is a typical tecchy, unfriendly digital interface.
Problem:
After a few months fault-free performance, it went dead, with no evidence of power to the device. Coincidentally, the mains circuit-breaker tripped out, isolating the kitchen (including the fridge-freezer!). The fuse in the mains lead to the CMT-CP11 was intact.
On returning the unit to the dealer, they replaced an internal fuse at no charge.
About 6 months later the same happened. This time the dealer replaced the unit.
Some months later the same thing happened. Again, the internal fuse was replaced.
Analysis:
I would guess this unit has a switch-mode power supply. Perhaps occasionally a mains spike causes a temporary overload and blows the fuse. The CMT-CP11 requires to be connected to the mains all the time - if it is disconnected, it looses all its channel settings after a few days (we have never bothered setting the clock!).
No other equipment in the house exhibits this sort of problem.
Perhaps the mains filtering/voltage limiting is rather poor in this design? Perhaps the power supply is rather close-tolerance?
A unit which requires to be connected to the mains all the time aught to be particularly tolerant of dirty mains.
Moan:
There is a tendency for new devices not to allow the user to disconnect them from the mains supply without inconvenience. (However our old Grundig VCR had battery backup for its memory - so why cannot other manufacturers do this). There is a good safety case for disconnecting devices from the mains when not in use. There must be a few power stations kept busy powering domestic devices which are in effect switched off!