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  1. J

    Strange old capacitor

    Wow, very instructive, i've made a leap foward !:) I am still curious why different symbols are used on the very same drawing ? They should have different meaning... Thanks again !
  2. J

    Pioneer LX-424 - Need Help

    When the contacts are oxidised black the cleaning is more complex. The contact board before buffing and after, plus the whole assembly. The perimeter contacts must be buffed with a small eraser via the free spaces by rotating the inner star tab wheel. *** Do not forget to put...
  3. J

    Pioneer LX-424 - Need Help

    If the contacts are copper looking, contact cleaner should do. But if the contacts are black or dark grey, it may be silver contacts... As encountered in some Samsui and Marrantz sets. These must be disassembled cleaned/buffed and treated with Deoxit. They come back to shiny silver state for...
  4. J

    Strange old capacitor

    I've just encounter another 3 lead capacitor. This time it's in a Phillips CM50A from 1948 this time. The shematic show two discrete capacitors C39 & C40. But this is the cap really in place an Aerovox Hi-Farad Dry Electrolytic Capacitor type PRS. 20 - 20 uF 450v Polarised. Someone change...
  5. J

    Strange old capacitor

    I will proceed with the replacement of all the capacitors and the out of specs resistor. Some have burning signs. May take a few weeks...
  6. J

    Strange old capacitor

    Fine, i just complete the localisation of all capacitors and resistors and their possible replacements. I've seen a few instances of capacitors labelled as "non inductive"... Where and when this is mandatory ? From what i've read, about anything will replace and be better that a "paper"...
  7. J

    Help Identify PJ742K chip

    This is not a "CHIP". This is a capacitor, inductor or a resistance... Just check if it have a reading of around 740kohm with a multimeter. If so it's a good resistor.
  8. J

    Pioneer LX-424 - Need Help

    Hi, it look like the pream is OK since the headphone have both channels. The emitter of Q17 is at 0.5 ohms (R77) from ground, that may be direct enough to trigger a continuty signal from some multimeter. But it didn't look like a problem, unless it's really measuring less than 0.5 ohms on the...
  9. J

    Strange old capacitor

    Yes, helped by a night of sleep and a morning coffe, i just understand. This cap is not related to the antenna, it's just physicaly tapping ground there for C12 capacitor. C12 is a 0.1 uf 200v cap from 6A8G pin 4 to the ground. So this schematic is OK !
  10. J

    Strange old capacitor

    Hi, while i was beginning the grocery list, i ran into a problem. There must be several version of the model 59... Because the schematic is not reflecting the circuit... There is no capacitor directly on the antenna connector on the schematic. But in the radio, there is a 0.1 uF 200 vdc...
  11. J

    Strange old capacitor

    Thank you very much for the info. So let's say the negative leads of the 3 electrolytics replacement caps will be common from the transformer and the positives will supply the 3 individual circuits. As long as these values are available, this is not a problem. Are they really electrolytics ...
  12. J

    Strange old capacitor

    Hi thank you very much for the lead as they also have tubes... I am not aware if such 1938 capacitor can still be OK or if i have to replace them all ? I figure that if i want to test them, i need to desolder at least one leg.
  13. J

    Strange old capacitor

    If there is no interaction between each one, i figure that 3 in paralllel may work. But these values are not available in electrolythics, what is the modern version of these parafin wrapped condenser ? It doesn't look polarised...
  14. J

    Strange old capacitor

    Hi, i am trying to recondition an old tube radio from 1938... There is this strange 4 leads capacitor wich i dont know how to verify and/or replace... It's operating at a pretty high voltage. Any idea ? Thanks.
  15. J

    Replace power MOSFET in subwoofer plate amp, Sledge STA-1000D

    I am also searching for this elusive IC101... If the pin#1 (still see a dot) is the one nearest to D103, then it have a ground at pin#4, conducting to the (-) of BR101 or TP5. So a suitable SOP-8 device may be the FA8C71N from Fuji Electric ? A guess to be confirmed...
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