Boston acountic horizon duo, how do I open it, It was connected to a 240 V and after that it stopped working. I thinking of opening it and fixing the power supply component.

If you are lucky, it only went in protection mode and after disconnecting the power for a little while and reconnecting things could come back. But if the system did not have an overload protection, a fuse can be blown, or worse the power supply or power amp can be blown to pieces. There is one thing semiconductors don't like is work over their limit.

You are not alone. Memory cap will be bad on front display board(C137) 0.33F/5.5v. Replacing cap will not fix, micro damaged as well. Probably can't turn off except with remote and display brightness stuck as well. Board NLA.

Needs front display micro or board replaced. No parts available.

In my case the blue LEDs were dead. It is pretty difficult to replace them by new SMD-LEDs but I managed it. Open the front, take out the board from the front part (5 screws). On one side of the LCD-screen you can see a white stripe with 3 resistors 101 (100 ohms). You must free this stripe form the plastic body on the left and right side (eg. by soldering iron). Solder out this stripe, on the other side you will find 3 very small smd-leds. Break them out and solder 3 new leds onto the board (left side = K). For control you can put 3 Volts to the Anode (A=+) and the Kathode (K=-) of this stripeboard before fixing it on the frontboard by soldering.

To perform a "soft reset"(all settings are erased)
Unplug radio
Hold alarm 1 button and plug in radio
Keep holding alarm 1 button until 3 numbers appear.
Release alarm 1 button and unplug radio.
Plug radio in and all will operate normally

Control micro is damaged due to leaky memory cap, .33F/5.5v on display board. Yellow glue used on these units turns brown and becomes both conductive and corrosive to the circuit board traces. built in obsolescence in my opinion to get you to buy new.

May i get the make and model # to help you more.

You can contact the BA. As they will make arrangement to take it back and replace it. BA is a good company and they give consumer feedback as soon as possible. Well, only if you haven't got an answer to your question.

I just received a email from BA re this issue. They were amazingly prompt and friendly. Here is what I was advised to do:

"One thing to try is to let the radio recalibrate itself, this is done by leaving the unit completely unpowered and unplugged for 48 hours to let the cap drain and the unit will recalibrate itself"

To fix: turn on unit, turn volume all the way down to 00, push and hold volume button for 10 seconds until beep then release, then turn volume all the way up to 50 (max) and push and release volume button.