Help! STRANGE problem with my walkman - Electronic Circuits Projects Diagrams Free

varun · 14th February 2004, 09:29 AM

Hi!
I have a walkman and i have managed to repair it somehow but there is a problem with it in the AM and FM band.In the AM band there is so much noise that it is difficult to listen any recption while tuning it but when a station is tuned properly the reception is clear when it is connected to my AC Adaptor this problem persists but it works properly when operated by two AA size cell,i am unable to remove the HUM of the AC Adaptor.I have replaced the filter capacitor with higher value(upto 1000uf/16V & 1000uf/50V) and used an inductor indeed but nothing works and the problem with the FM band is that it is picking up so many new stations(like CHINA RADIO INTERNATIONAL,CHANNELS OF ARABIC LANGUAGE i guess probably from pakistan or Afganistan but i am not sure about that etc.) which i never heard before while using it before i repaird it,sometimes these channels are also heard on the AM band and
sometimes don't.Well it is also picking up some cable channels like STAR MOVIES as there is a cable amplifier installed about 30-40 meter away from my room.The make of the walkman is CASIO.please help me why this is happenning and how i can rectify these problems?

mozikluv · 14th February 2004, 11:18 AM

hi,

usually this ac adaptors that you have now is not a good source to power your walkman. you are on right track to increase the capacitance value to reduce the equivalent series resistance of your cap. but you have to regulate the output. you will just have to spend more by using LM78l05 - TO-92, a transistor like a 2n3904, a zener diode- 3.6v, 2 pcs of mylar capacitor 0.47uf 50v. is your walkman operating at 3v? using those i suggested will give you a voltage of 2.8v to 2.9v regulated.

any problem pls. feel free to email me.

Sebi · 14th February 2004, 11:40 AM

Try out this circuit.The two 4n7 capacitors very important against cross-modulation.

varun · 28th February 2004, 05:32 AM

Hi! MOZIKLUV
thank you very much for the help.well i was busy thats why i couldnt reply early.welli'll trouble once again in future,i hope u'nt mind.i'll try to implement that power supply ckt soon and tell the results but the problem of receiving other stations exists if possible please tell me about that also.tell me if i can use FM DXing in the same ckt for clear reception of all the distant channels.
bye

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14th February 2004, 09:29 AM	(permalink)
varun	Help! STRANGE problem with my walkman Hi! I have a walkman and i have managed to repair it somehow but there is a problem with it in the AM and FM band.In the AM band there is so much noise that it is difficult to listen any recption while tuning it but when a station is tuned properly the reception is clear when it is connected to my AC Adaptor this problem persists but it works properly when operated by two AA size cell,i am unable to remove the HUM of the AC Adaptor.I have replaced the filter capacitor with higher value(upto 1000uf/16V & 1000uf/50V) and used an inductor indeed but nothing works and the problem with the FM band is that it is picking up so many new stations(like CHINA RADIO INTERNATIONAL,CHANNELS OF ARABIC LANGUAGE i guess probably from pakistan or Afganistan but i am not sure about that etc.) which i never heard before while using it before i repaird it,sometimes these channels are also heard on the AM band and sometimes don't.Well it is also picking up some cable channels like STAR MOVIES as there is a cable amplifier installed about 30-40 meter away from my room.The make of the walkman is CASIO.please help me why this is happenning and how i can rectify these problems? __________________ varun pratap singh

14th February 2004, 11:18 AM	(permalink)
mozikluv	power supply hi, usually this ac adaptors that you have now is not a good source to power your walkman. you are on right track to increase the capacitance value to reduce the equivalent series resistance of your cap. but you have to regulate the output. you will just have to spend more by using LM78l05 - TO-92, a transistor like a 2n3904, a zener diode- 3.6v, 2 pcs of mylar capacitor 0.47uf 50v. is your walkman operating at 3v? using those i suggested will give you a voltage of 2.8v to 2.9v regulated. any problem pls. feel free to email me. __________________ \"NONE BUT THE BRAVE DESERVES THE FAIR\" ~Shakespeare~

28th February 2004, 05:32 AM	(permalink)
varun	thanks for the help Hi! MOZIKLUV thank you very much for the help.well i was busy thats why i couldnt reply early.welli'll trouble once again in future,i hope u'nt mind.i'll try to implement that power supply ckt soon and tell the results but the problem of receiving other stations exists if possible please tell me about that also.tell me if i can use FM DXing in the same ckt for clear reception of all the distant channels. bye __________________ varun pratap singh