Title: Johnson 500 Arcking inside PS Post by: rich on April 13, 2006, 09:26:04 AM Hi
I fixed the problem arcking on the HV pin on rear of power supply. Now the only problem seems to be when I unkey it I will get a loud arck like fire cracker noise in power supply. Not everytime I unkey, It could do it the first Time I unkey or hours later. Usually once or twice during a few hours use. It does'nt seem to do it when talking, Just when I unkey. Like I said not all the time, just once or twice within a few hours use. I think I saw it come from the static bleeder in power supply. Thanks for reading and any help would be great. Rich Title: Re: Johnson 500 Arcking inside PS Post by: WV Hoopie on April 13, 2006, 11:45:00 AM Hello Rich,
Check out page 28 of the operation manual. Under Arc Gap Adjustments: "When the high voltage is turned on and off there may be a brief arc." I don't like loud arcs! I lost my mod transformer a few days ago and don't have a warm fuzzy feeling about arcing today. So, I'm waiting for the circuit description/modification from Skip, K7YOO. We might have a relay sequencing issue, on unkeying the "500" in the AM mode, RY303 must open first - then RY302. Both have DC coils energized by the bias supply. Looking at the schematic there is NO capacitor across the coil of RY302. RY302 should be a slow release relay. I don't know how this is achieved, mechanical friction and or electrical design? Not a good answer, just food for thought. 73's wd8kdg Craig Title: Re: Johnson 500 Arcking inside PS Post by: rich on April 13, 2006, 01:21:19 PM Hi Craig
But it does'nt do it everytime I unkey, Just once or so in a few hours use? You still think that may be it? Thanks..Rich Hello Rich, Check out page 28 of the operation manual. Under Arc Gap Adjustments: "When the high voltage is turned on and off there may be a brief arc." I don't like loud arcs! I lost my mod transformer a few days ago and don't have a warm fuzzy feeling about arcing today. So, I'm waiting for the circuit description/modification from Skip, K7YOO. We might have a relay sequencing issue, on unkeying the "500" in the AM mode, RY303 must open first - then RY302. Both have DC coils energized by the bias supply. Looking at the schematic there is NO capacitor across the coil of RY302. RY302 should be a slow release relay. I don't know how this is achieved, mechanical friction and or electrical design? Not a good answer, just food for thought. 73's wd8kdg Craig Title: Re: Johnson 500 Arcking inside PS Post by: WV Hoopie on April 13, 2006, 05:27:32 PM Clue-less on this end. Mine would arc at GAP301 once in a blue moon, only on unkeying. :-\ I think the gap, GAP101, in the RF deck zapped once in a year and a half, now that was impressive, loud. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Need someone with relay experience to chime-in and tell all there is to know about RY302 in the Junkston "500". wd8kdg craig |