New TL-922 Owner

Discussion in 'Amateur Radio Amplifiers' started by G3YRO, Dec 14, 2016.

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  1. G3YRO

    G3YRO Ham Member QRZ Page

    Well, to be on the safe side, I turn the Amp ON and OFF using the mains switch on the wall (as it's right next to the Amp) . . . so the on/off switch on the Amp is never used.

    But turning it ON via my Manual Soft Start switch I guess saves the Valve Filaments, Transformer and the Capacitors.

    Well mine had NO mods whatsoever either . . .

    After reading ALL the web pages I could find, some suggesting Modifications, others saying those Mods were stupid, the only thing I decided to do was directly ground the grids to chassis.

    This is very straightforward, just remove the bottom panel, and you get rid of lots of components.

    Adding Soft Start is certainly desirable to prolong the life of the items mentioned . . . but rather than build a Soft Start circuit into the amp, I just have an external 22 ohm resistor in the Mains Lead with a switch across it . . . I turn the Amp on then throw the switch 1 second later.

    I use a footswitch on CW, so have no desire to add any Break-in fast switching relays.

    However . . . you'll probably get ten different opinions on here !

    Roger G3YRO
  2. WA7PRC

    WA7PRC Ham Member QRZ Page

    @W8SPM: email sent
  3. W4JFA

    W4JFA Ham Member QRZ Page

    I have this...
    When you get to the web site click "download the manual" It has great detailed instructions and hi res photos. Worth every penny!
    I'm not affiliated with them, just a happy customer.
  4. W4JFA

    W4JFA Ham Member QRZ Page

    Roger, What wattage resistor are you using?
  5. G3YRO

    G3YRO Ham Member QRZ Page

    A 10 watt one (running on 240V) . . . this style:

  6. WA7PRC

    WA7PRC Ham Member QRZ Page

    $400 is a lot of pennies. The W7RY setup costs a lot less. You also get continuously variable operating bias.
    The square "sand" resistors are notorious for not liking yuuuge inrush current, and failing. I used Dale encapsulated resistors in my step-start circuit around 1980:
    They're still good. Vitreous enamel resistors are also a good choice.
  7. G3YRO

    G3YRO Ham Member QRZ Page

    Possibly . . . but mine has never failed ! And you can buy them up the road in my local Maplin.

    Roger G3YRO
  8. WA7PRC

    WA7PRC Ham Member QRZ Page

    Aside from use in ham stuff, a friend worked for several decades as a TV service tech. He has also said they're awful.
    Maplin is convenient (for you) but, convenience isn't in itself a reason to buy something.
  9. G3YRO

    G3YRO Ham Member QRZ Page

    Well the point is it hasn't failed yet . . .

    And if it DOES it would take 2 minutes to replace it . . . so no big deal !

    (I also notice that some of the commercially available Soft Start Boards use resistors like that too . . . so they can't be that bad)

    Roger G3YRO
  10. WA7PRC

    WA7PRC Ham Member QRZ Page

    That's ONE (so far).

    The goal is to not need to replace parts, even if it takes only 2 minutes (not including the time it takes to procure the replacement).
    ! <-- matching exclamation mark added for equal emotional emphasis.

    I notice that those using sand resistors in a step start circuit are the ones that have a high failure rate. This follows what my TV service tech friend experienced over several decades. They used them 'cuz they were cheap, and needed to last only past the warranty.

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