Ad Widget

Collapse

Announcement

Collapse
No announcement yet.

Orange AD140 HTC low output

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Orange AD140 HTC low output

    i have an '02 orange AD140 HTC here. fizzy output sound, VERY quiet. tubes test OK. have tried other tubes.
    using a probe, i find the signal is strong coming out of the preamp and into pin 5 of the power tubes, seems to be behaving normally. i'm using this schematic: http://elektrotanya.com/PREVIEWS/634..._amp.pdf_1.png
    i try to get a signal to the probe off of pin 3 from the power tubes and i find that same fizzy sound that makes it to the speaker. i did a diode test from pin 3 to ground to see about D1 and D2, and it came back to me as a voltage drop of 1v. normal diode is supposed to test at around .5v.
    D1 and D2 are in parallel to ground, but testing 2x known-good diodes in parallel doesn't read 1v. the meter still reads .5v.
    the board is a pain to get out of the chassis, i'm hoping someone here has some input about what the problem might be. i'm wondering if something is going on w/ D1 or D2 or if my 1v reading is normal?

  • #2
    update: there ISN'T a D1 or D2. unless maybe they were placed elsewhere on the board.

    Comment


    • #3
      really need some help on this. stuck. probe on output of preamp tubes to listening amp sounds totally fine. probe on pin 5 of poweramp tubes to listening amp sounds totally fine and amp behaves normal.
      something in the power amp is not doing what it's supposed to and it's either so simple i overlooked it or it's just something i've never seen before and it's just over my head until i it's explained to me.
      help!

      Comment


      • #4
        The plates of the 6L6 tubes get there voltage from the B+ through the OT winding.
        If all the voltages are present & there is not any undue ripple on the B+ nodes, the next step is to sub another output transformer.

        Comment

        Working...
        X