ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
So I bought this amplifier/tuner (220V supply version) with the seller claiming it to sometimes switch on standby out of nowhere. This seems a lot more than sometimes.
After plugging it in and leaving it alone for about 10 seconds, it starts to select FM2 and then toggles back and forth to standby randomly. If I hold my finger on the tape select for example, it stays there and toggles the standby a little less frequently. I also kept my phone away to rule out that sort of interference.
I recon the touch controls have gone bad but does anybody have an idea what might be causing it?
I'm an electric engineering student so i'm going to open it up to see what I can find, but I don't know how to service these controls.
*edit* I opened it up and found an impressive construction that makes it difficult to get to certain parts. I did find some easily accessible trim pots under the bottom cover plate so I'm hoping I can trim one these to fix the touch control. Maybe the problem is in a couple of caps, considering the time it takes to malfunction? I didn't take the time to get to the circuit under the 'sensi-touch' panel so i'm not certain what's going on in there. I'll await your answers until I start taking it apart completely. Incidentally it's the first B&O thing I've ever owned but i'll spare the design praise of these systems. Thanks for reading.
*another edit* After leaving it plugged in for a good while (at least 30 minutes) there is no change in the behavior except that the controls become completely unresponsive most of the time. The only things that always seems to work are the volume control and volume store functions.
Most likely ripple and/or jitter of some kind from the power supply unless the Beomaster has been placedright next to something that emits radio noise.Put a scope on the power rail to the sensor circuits and take a look.
Martin