Repair of a Pioneer SX-450 that puts a hum on the speakers

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  • Опубликовано: 21 дек 2024

Комментарии • 8

  • @dannyboy6114
    @dannyboy6114 Год назад

    Hi my speakers make a loud pop when switching on the amp and crackle when turning the volume and lose sound in one speaker sometimes when doing this. Anyone else had this problem. Is it an easy fix. I seen someone put resistors in speaker connectors but I don't want to be doing this.

    • @orangevalleysystems
      @orangevalleysystems  Год назад +1

      It looks like that receiver doesn't have a speaker protection relay fitted that normally connects the speakers to the amp a few seconds after switch on. If you connect the speakers to the B output you can then switch it on by putting the switch to the speaker A or speaker Off position then after a few seconds move it to the speaker B position. The crackle and loss of sound can often be fixed by spraying some contact cleaner into the volume control pot.

  • @hokman1
    @hokman1 2 года назад

    Hi there, sorry I am located in HK. I got the loud100hz hum that isn't volume dependent with this, was that the problem you have encountered?? I have replaced the 2 main power caps with no avail.

    • @hokman1
      @hokman1 2 года назад

      after inspecting the schematic, are they c109/c110 caps for the left and right tone controls? 0.33uf/35v|
      thanks

    • @orangevalleysystems
      @orangevalleysystems  2 года назад

      @@hokman1 Hi, the failed capacitor I had was C305, a 220uF 50v. The capacitor for that supply powers the tone controls and the turntable preamp. My notes show that the 36.5v rail with the failed capacitor measured 30v on a multimeter although it's easier to see how bad it is on an oscilloscope if you have one.
      I guess the level of hum and measured voltage will be dependent on how failed the capacitor is.

    • @hokman1
      @hokman1 2 года назад

      @@orangevalleysystems It worked, thanks very much sir! serious problem solved with a cheap part

    • @yanng3790
      @yanng3790 2 года назад +1

      @@orangevalleysystems Hi it's exactly true what you say I am currently repairing this amp the capacitor c305 220uf/50 volts is defective, I will replace the 2 soon I only have sound on the left channel and no sound on the right channel with background hum on both channels

    • @drewmckellar8603
      @drewmckellar8603 Год назад

      @@yanng3790 I have that same problem. So far I noticed a 150 ohm resistor next to the output transistors completely burned up. And that transistor it is with also tested bad