Re: SX-28A Hum
¿ªÔÆÌåÓýThanks Jacques, well that seems to pour cold water on the magnetic coupling theory. If the trace I copied is typical {I don¡¯t know}¡ ie; assuming? that hum is 60 cps with third harmonics at /I n /close to the choke, there can be electrostatic coupling by close parallel wires from AC incoming wires being too close to the? choke ??wires. ??? Moving stuff might mean moving wires and coupling. I worry more about long wires running to the switch. ?Another long shot.? ¡ but the old stories of just moving stuff raises its head. I¡¯m dried out. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jacques_VE2JFE via groups.io
Sent: Wednesday, February 19, 2025 3:04 PM To: [email protected] Subject: Re: [HallicraftersRadios] SX-28A Hum ? In a SX-28A, the CH2 is as far as it can be from the power transformer: ? ? ? The black ¡°core¡± at the left is the CH2. You can see the bottom of the power transformer and the filtering choke at right. The closest transformer to the CH2 is the audio output. ? ? 73, Jacques, VE2JFE in Montreal ? De?: [email protected] <[email protected]> De la part de don Root ? Tom and/or anybody still tuned in. Still looking for what really failed and how. For anyone wondering about the details and possible source, I copied a bit of your first Video so I could take a closer look. I see 60 Hz and strong third harmonics, and no visible high harmonics. It reminds me of core saturation. Power transformer magnetics and primary is the only source I can think of. Any comments?
_._,_._,_ -- don??? va3drl |
don Root