repurposing a power supply

Discussion in 'Homebrew and Kit Projects' started by KJ7VAB, Aug 23, 2021.

ad: L-HROutlet
ad: l-rl
ad: HRDLLC-2
ad: Left-3
ad: Left-2
ad: L-Geochron
ad: abrind-2
ad: MessiPaoloni-1
ad: L-MFJ
  1. WA9SVD

    WA9SVD Ham Member QRZ Page

    I've run across some "ATX" supplies that DO require a load, but as you say, they may be "older" types, and not be built according to the latest standards. If the OP uses an LM338 type regulator, most of the manufacturers DO say that additional capacitance (1µF t0 1000 µF) on the OUTPUT will improve transient response.(Surprise?:confused:) I would suspect the same for most any power supply. I can USUALLY tell just by weight alone if a "wall-wart" is a switcher or a transformer/rectifier (linear?) supply, and I haven't run across any transformer-type wall-wart or laptop supply that is rated for much more than 1 Ampere, making such "wall-wart" or laptop supplies unsuitable for the OP's use or needs.
  2. KJ7VAB

    KJ7VAB Ham Member QRZ Page

    I have a 20v 11A "laptop" power supply from a Boxx Technologies mobile workstation. Has a workstation motherboard in a massive 20lb 17" case.
    Has some weird 4 pin plug.
    Seems like an easier project than the ATX. I used an old mother board today as a "dummy load". Plugged one of the 12v outputs into the 818nd and it was just as noisy as the wall wart that shipped with the 818.
    So then I pulled my APC UPS apart and stole a bunch of the ferrite torroids and wound the wall wart and antenna through and around them as many times as I could. Now 80meters is quiet with the wall wort plugged in. 160 isn't, though.

    Reading through a bunch of the articles posted here. Thanks for all of the info!


Share This Page