Recent content by gerryt

  1. gerryt

    Help Reading a Schematic

    Thanks for your reply, I have attached the schematics. I am wanting to know how to connect a different pre amp board (picture attached) into the power amplifier. (J1)
  2. gerryt

    Help Reading a Schematic

    I am working on the pre amp/power amp board connections for a Mackie SRM150 personal monitor. Is there someone who might be willing to help me read the schematic? I am still learning about how to do this better. I need to put a different pre amp into the power amp as replacement boards for...
  3. gerryt

    Electro Voice SXA Powered PA Cabinet - Baffling Loud Hiss/Static

    Solder side of PCB is attached. Here is the brochure link: https://products.electrovoice.com/binary/SxA-Series-Flier.pdf And thanks for the reminder to be gentle.
  4. gerryt

    Electro Voice SXA Powered PA Cabinet - Baffling Loud Hiss/Static

    I have an Electro Voice SXA 100+ powered PA speaker with a peculiar problem. At times i get a loud fuzzy hiss/static through the tweeter. There is no hiss with the woofer speaker. I tested the tweeter horn driver by connecting it to another amplifier and it works fine. My research online...
  5. gerryt

    Preamp output very weak

    Yes, I agree, I was not very clear about what I did, so I will attempt to describe with greater clarity. Played music from my CD player headphone output using a TRS 1/4" input into JB7 (return) Sound that resulted was loud and clear. Plugged same cable with same CD player source into JB3 and...
  6. gerryt

    Preamp output very weak

    I am attempting to repair a Yorkville KW100 (schematic attached). When I plug a music source into the return input which goes directly to the power amplifer section of the unit I get a clear loud musical output from the speaker. However when I plug the same music source into input channel one...
  7. gerryt

    Input Hum - Yorkville Amplifier

    I am now starting to work on the second amp, it is exactly the same, a Yorkville 100KW. But this one has a different problem. Channel two has very low gain even at full volume. If I use the return input, there is lots of volume, so the power amp is working fine. Any thoughts as to what might...
  8. gerryt

    Input Hum - Yorkville Amplifier

    The op amp was not socketed, pin mount to the board, I looked at all the contacts carefully and they seemed to be ok.
  9. gerryt

    Input Hum - Yorkville Amplifier

    Thanks everyone for your help on this problem. I replaced the op amp and the problem is resolved.
  10. gerryt

    Input Hum - Yorkville Amplifier

    After running the various tests that you so kindly suggested I replaced the op amp. (U2) Problem solved!
  11. gerryt

    Input Hum - Yorkville Amplifier

    Thanks for the lead about turning a laptop into a scope. I have an older spare laptop, I will give this a try. I tested the op amp on diode mode with my multimeter and it seems to be working fine. I also tested for other ground faults. The tip and ring tabs on my 1/4 input, and in the XLR...
  12. gerryt

    Input Hum - Yorkville Amplifier

    I found C34 on the schematic, attached and circled.
  13. gerryt

    Input Hum - Yorkville Amplifier

    The traces are all connected. I cannot find C34 on the schematic (weird) but it does show up on the schematic with all of the traces shown. (see attached). I do not have a scope to test the signal path. I cleaned the pot, but I am thinking I will replace it just to be sure it is not the...
  14. gerryt

    Input Hum - Yorkville Amplifier

    I replaced C6, no change. Channel Two is clean and Channel One hums, even with nothing plugged in to the inputs. I checked all of the ground circuits with a meter. Can't find or see any faults. Wondering if the op amp (U2) in channel one is the problem. Here are the pictures of the Input...
  15. gerryt

    Input Hum - Yorkville Amplifier

    I replaced with C6 with a new capacitor, the problem remains. Wondering if it could be the op amp - U2 on the schematic?
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