Chuck wrote:




The light dimmer was putting an enormous amount of hash on the mains;
somehow it was getting into the microprocessor circuitry. I had seen
this before on much cheaper items so I had a hunch that this was the
problem.



** Wall dimmers put large voltage spikes on the wiring going to the lamp/s concerned - two spikes per cycle at up to the peak AC voltage. This radiates as buzzing noise across the audio and also AM radio bands.

Well shielded, low impedance gear is not affected but anything high impedance and not well shielded picks it up. Electric guitars and some keyboards are particularly susceptible.

Seems your Tandberg was too and that is **** poor design.


..... Phil