I share this with my fellow Flexers because I see occasional reports of scratchy audio on the reflector.
Ive had my 5000A for 3 years, and during the past year it has exhibited increasingly scratchy audio only when using headphones plugged into the front panel jack. It was obviously a hardware problem because I could affect the severity by just touching the headphone leads or jack. Initially I suspected the wires, the 1/8 plug to ¼ plug adapter and dirty contacts. After a series of meticulous tests, I ruled out each of these and concluded the problem was internal, probably a defective jack or poor solder connection to the PC board. When my audio noise became worse than my summer QRN on 80m, I couldnt take it anymore, so I reluctantly opened up the case, removed the RX2 and examined the headphone jack. All appeared normal except for a factory add-on to the sleeve/ground contact. This modification consisted of a tiny copper L-bracket soldered to the contact. The bracket was covered with an EMI/RFI gasket material attached by an adhesive backing. The gasket material, which I believe is called a fuzz button, is similar to super-fine steel wool. The resistance between the jack sleeve contact and chassis ground was 12 and 39K ohms respectively with and without the fuzz button contact, so I concluded that the intended purpose is to make contact with the front panel, possibly a fix for FCC or CE type certification. I listened to the audio quality and loudness with and without the sleeve at chassis ground potential and could detect no difference. My fix was to remove the copper L-bracket and gasket material, solder a #24 AWG wire to the sleeve contact on the jack and ground it via a solder lug attached to the stud supporting the PC board. The result is clean, crisp audio all the time. However, I believe the external ground is optional. Ron -N0RR _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
