Translate this page:

Want to share: Have downloaded the schematics from this forum to help repair the amplifier of a friend. Turned out that Sony decided to route the earth through the chassis, even the earth between the various supplies. When one takes the main board out of the chassis and switches the amp on, there are up to 20 volts difference between the eart (and hence reference) of the pre-amps and the main amps. Luckily the amp goes into protection but from a design point of view it is not nice to rely on screws and aluminum face plates to conduct up to 0.2 amps of current from one supply to another. What I did is solder wires to every eart point and connected them on the main board to make it stand alone and not rely on conducting current through the chassis anymore. Bad design, simple repair but took some digging in the schematics to find out what exactly was going on!

hi, i tried twice but both files are corrupted. would appreciate a correction. thanks

Hi,

Mine sony amplifier TA-F444ES needs a (alphs) balance potentiometer pn 1-228-905-00 res,var,carbon 50k/50k with center detent.
Anyone who knows a reliable source ? shaft 6mm length shaft 2cm diameter potmeter 16mm

Sziasztok. Volna itt a fent említett autórádió ami a nagyszüleimé. Olyan gondja volna amit nem tudom mitől van, hogy hol szól a rádió hol nem. Ha nem szól akkor egyszerűen nem fog semmit. Olyan mintha az autóantennával volna gondd, de nem azzal van. Valami nem stimmel az autórádión az antennarésznél szerintem. Az volna a kérdésem hogy mi lehet ez, vagy hol tudok elindulni a probléma felkutatásában?? Előre is köszi a segítséget. Üdv, Zoli