FM radio & MP3 player

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Category: Misc
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     Using one like this radio & MP3 player and PC speakers a kitchen sound system is done. The potensiometers had problems and was taken off. Also a pair of resistors in series with incoming audio was removed increasing the produced audio. The bass potensiometer was also removed replacing it with 2*2 proper resistors simulating the desired adjustment. The power switch was also sort circuited. The speakers had an internal 12V power supply that has removed. I plan to use the 220 V cable but I discover that I can put a power connector to the PCB. I use 13.8 V power supply with battery backup to power first the FM & MP3 player. I steal the voltage tha drives the power LED to drive a BC547 and a relay to switch the power to the speakers. So I do need to switch ON&OFF also the speakers. 

Note !!!     

     The internal 78M05 do not have at 12 V a capacitor and it self oscillates !!! You must add a capacitor, I use a 100uF/25V directly connected at the power connector. The circuit has no protecting diode for reverse polarity and you can safe put one in series as the 12 V is far away than the required 8 V that 78M05 need.

An MXQ TV BOX from eBay was added. It is a classic Android box that requires 5V that was supplied from a 12V to 5V 3A from eBay. Audio output is inserted at monitor. The LCD monitor is a repaired 17'' which had a bad electrolytic capacitor. The monitor has a DVI input but it can not work with 1024*720 @ 60Hz that produce the MXQ using a digital DVI to HDMI adapter. A HDMI to VGA adapter is used instead that works.

     This is the project of my friend.