dcgillespie's Recent Activity

  1. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    It would seem to be showing something. The bottom indices are distinctly different that the top ones. You might check it against another...

    Feb 19, 2018 at 10:56 AM
  2. dcgillespie replied to the thread Another DG-SE1as a first project.

    Very nice clean up! Dave

    Feb 19, 2018 at 10:51 AM
  3. dcgillespie replied to the thread More Fun With Magnavox: The 9300 Series.

    RJ -- Frequency response measurements are standardly made with sine waves at a power output level of 1.0 watt RMS into the rated load,...

    Feb 19, 2018 at 10:49 AM
  4. dcgillespie replied to the thread Next up a PSE Flea powered amp - the Mighty 71-A.

    Very interesting! And a very purdy chassis too....... Dave

    Feb 19, 2018 at 10:34 AM
  5. dcgillespie replied to the thread Fisher's Original Bad Boy: The 50A Power Amplifier.

    New Input Stage Design In the original design of the 50A, V1 serves the dual function of acting as a single stage input preamp, and...

    Feb 19, 2018 at 10:27 AM
  6. dcgillespie replied to the thread Fisher's Original Bad Boy: The 50A Power Amplifier.

    Final Modifications for the 50 Series Amplifiers NFB and HF Stability Circuits So with the performance information digested from all...

    Feb 19, 2018 at 10:25 AM
  7. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    To me, that points to an issue with the 38 kHz oscillator, as in the outputs are not equally balanced to ground on each half cycle. You...

    Feb 16, 2018 at 10:23 AM
  8. dcgillespie replied to the thread 1950's President found.

    Is there any known existence of a service manual for the control unit? Dave

    Feb 16, 2018 at 10:17 AM
  9. dcgillespie replied to the thread 1950's President found.

    The FM tuner, power amps, and phono preamps are pretty standard stuff in the Fisher stable. The AM tuner not nearly so much as I'm aware...

    Feb 16, 2018 at 6:39 AM
  10. dcgillespie replied to the thread Tung-Sol 6550 Type Three now installed in "Harry Gates" Amp.

    Neat amp! I haven't heard of Harry, but his design certainly looks interesting. Like (apparently) Harry, I wouldn't miss the overly...

    Feb 16, 2018 at 6:33 AM
  11. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    Go back to post 418. You proved that the right modulator balances to 6 mV regardless of which way it was connected across the 38 kHz...

    Feb 16, 2018 at 6:05 AM
  12. dcgillespie replied to the thread 1950's President found.

    What a time piece! All in tack and converted to stereo, too! Vendo must have a heavenly connection with Avery......... Beautiful, rare,...

    Feb 15, 2018 at 9:34 PM
  13. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    We're back to something I've always championed: Something you think is true, is not. If: 1. The CT of the 38 kHz transformer is...

    Feb 15, 2018 at 9:14 PM
  14. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    A ring is a ring is a ring -- they're all the same. The ground lead is always grounded. The modulator/demodulator input/output lead...

    Feb 14, 2018 at 6:25 PM
  15. dcgillespie replied to the thread fisher MPX decoder troubleshoot.

    That works great too. I use the 1N459A as well, which like the 1N4148, is a low leakage, hi conductance silicon diode. Dave

    Feb 14, 2018 at 12:13 PM