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S-38C Question

Howard All Messages By This Member #31422 Hey guys, was just about to replace the power supply filter in my S-38C.? opened it up and found a blown up bumblee capacitor.?? The cap in question is C-27? a .02uF @600v? which goes from one side of the line to the common ground ( NOT chassis ground). ? My question is, can this be replaced with a .047 uF "safety" capacitor, or is the value of .02uF critical? ? Please let me know as I do want to keep the old beast running. ? Thank you. ? ? Howard
Bob Kirkeby All Messages By This Member #31423 The value is not critical. The .047 safety cap should be fine. 73 Bob "Kirk" W?HNV toggle quoted message Show quoted text On Mon, Dec 30, 2024 at 12:20?AM Howard via <n9ktw=[email protected]> wrote: Hey guys, was just about to replace the power supply filter in my S-38C.? opened it up and found a blown up bumblee capacitor.?? The cap in question is C-27? a .02uF @600v? which goes from one side of the line to the common ground ( NOT chassis ground). ? My question is, can this be replaced with a .047 uF "safety" capacitor, or is the value of .02uF critical? ? Please let me know as I do want to keep the old beast running. ? Thank you. ? ? Howard
Michael McCarthy, W1NR All Messages By This Member #31424 Value is not critical, but voltage rating needs attention. I would use a 250v A.C. rated disc ceramic, or else one with a rating greater than 1000v D.C. I would also check (or replace) the resistor R22 and capacitor C24 as these have probably aged as well. Next, be sure it has a polarized plug with hot going to the switch. Even though it is not considered a "hot chassis" radio, hot side should be switched for maximum safety. toggle quoted message Show quoted text On 12/30/2024 1:20 AM, Howard wrote: Hey guys, was just about to replace the power supply filter in my S-38C.? opened it up and found a blown up bumblee capacitor.?? The cap in question is C-27? a .02uF @600v? which goes from one side of the line to the common ground ( NOT chassis ground). My question is, can this be replaced with a .047 uF "safety" capacitor, or is the value of .02uF critical? Please let me know as I do want to keep the old beast running. Thank you. Howard _._,_._,_ -- 73 de Mike, W1NR THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming! - Ruk -
Michael McCarthy, W1NR All Messages By This Member #31425 I should have added that changing to a polarized plug requires re-wiring the on/off switch. Not needed if the chassis passes the "hot" test. See toggle quoted message Show quoted text On 12/30/2024 9:17 AM, Michael McCarthy, W1NR via groups.io wrote: Value is not critical, but voltage rating needs attention. I would use a 250v A.C. rated disc ceramic, or else one with a rating greater than 1000v D.C. I would also check (or replace) the resistor R22 and capacitor C24 as these have probably aged as well. Next, be sure it has a polarized plug with hot going to the switch. Even though it is not considered a "hot chassis" radio, hot side should be switched for maximum safety. -- 73 de Mike, W1NR THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming! - Ruk -
Jim Whartenby All Messages By This Member #31426 If the neutral side of the line is directly connected to the chassis and the hot side is now connected to the ON/OFF switch, what is to be done if the AC hum or other noise picked up from the AC line is now worse?? The idea behind the original wiring was to keep the high side of the AC line away from the high impedance and gain of the audio amplifier circuit since the ON/OFF switch is located on the volume control. I do not believe that the NEC controls how a manufacturer connects to the AC line, that is the responsibility of the Underwriters Laboratory.? At the time the AA5s were made, they received the U/L sticker.? If one is concerned about a shock hazard form an AA5 radio, one can always connect it to a GFCI outlet.? It will trip when the current imbalance between the hot and neutral is greater then 15 mA. My workshop is in the basement.? All of the outlets in the basement are GFCI protected because of the concrete floor. HNY,? Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy On Monday, December 30, 2024 at 08:41:00 AM CST, Michael McCarthy, W1NR via groups.io <lists@...> wrote: I should have added that changing to a polarized plug requires re-wiring the on/off switch. Not needed if the chassis passes the "hot" test. See toggle quoted message Show quoted text On 12/30/2024 9:17 AM, Michael McCarthy, W1NR via groups.io wrote: Value is not critical, but voltage rating needs attention. I would use a 250v A.C. rated disc ceramic, or else one with a rating greater than 1000v D.C. I would also check (or replace) the resistor R22 and capacitor C24 as these have probably aged as well. Next, be sure it has a polarized plug with hot going to the switch. Even though it is not considered a "hot chassis" radio, hot side should be switched for maximum safety. -- 73 de Mike, W1NR THAT was the equation. EXISTENCE!... SURVIVAL... must cancel out... programming! - Ruk -

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