SR-150 PWR Supply
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Hi Folks, Happy New Year, Replacing a garbage 18 gauge AC cord that someone installed in the power supply.? I see the guy wired the neutral side to the fuse. I always thought the hot side went to the fuse, just like in the breaker panel.? In a 110 VAC line,?the "hot" wire should always be connected to the fuse in a device, not the neutral wire;?meaning the fuse should be placed on the side of the line carrying the live current.? Explanation:
Thoughts Welcome, dave wa3gin |
开云体育Dave,? ya… 4 more hours and the year is Gone. ? Back when this stuff was made,? the identity of hot and neutral should have made it to the back of the outlet but there was no such identity at the front so the idea of hot and neutral? did not make it into a radio or anything? using a normal outlet.? Once you/we ?modify the cord and Outlet to be polarized we have a new situation so a fuse can be put in the “hot”? wire. etc ? From: [email protected] [mailto:[email protected]] On Behalf Of Dave Jordan via groups.io
Sent: Tuesday, December 31, 2024 5:49 PM To: [email protected] Subject: [HallicraftersRadios] SR-150 PWR Supply ? ? Hi Folks, Happy New Year, ? Replacing a garbage 18 gauge AC cord that someone installed in the power supply.? I see the guy wired the neutral side to the fuse. I always thought the hot side went to the fuse, just like in the breaker panel.? ? In a 110 VAC line,?the "hot" wire should always be connected to the fuse in a device, not the neutral wire;?meaning the fuse should be placed on the side of the line carrying the live current.? Explanation: ·?????? Safety: Placing the fuse on the hot wire ensures that when a fault occurs and the fuse blows, the appliance is completely de-energized, preventing potential shock hazards if someone touches the device while it's faulty. Thoughts Welcome, dave wa3gin -- don??? va3drl |
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Ok, but for me during my ham years starting in 1963 the smaller of the two socket openings was always hot. The smooth side of the cord was always hot as well.? Funny how time seems to change things…but those standards remain the same even today.? Happy New Year Dave Wa3gin On Tue, Dec 31, 2024 at 8:04?PM don Root via <drootofallevil=[email protected]> wrote:
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开云体育Well Dave. if in 1963 you had? one slot smaller than the other, you were ahead of the game; the house I am in [1956] was all non polarized, except for the Garage, washing machine and outdoor outlets. ? The drawing indicates nothing about any polarity for the PS 150.? if I were putting a new 2 wire polarized plug ?and cord and on one, ?the hot would go to the fuse as you mentioned ?. ? of course the chassis/cabinet will tend to float at ?some ?midway voltage due to the ?two 1400 volt line caps connect to ground also, just as before ? I would have a little dilemma ?if I were putting a ?new 3 wire ?plug ?and cord on one, as where would the ground wire go? Other than the chasses? But then it would connect? Neutral to ground, and that would defeat the intent of the NEC code ?and GFCI on that circuit.? ? ?
enddd From: [email protected] [mailto:[email protected]] On Behalf Of Dave Jordan via groups.io
Sent: Tuesday, December 31, 2024 8:14 PM To: [email protected] Subject: Re: [HallicraftersRadios] SR-150 PWR Supply ? Ok, but for me during my ham years starting in 1963 the smaller of the two socket openings was always hot. The smooth side of the cord was always hot as well.? ? Funny how time seems to change things…but those standards remain the same even today.? ? Happy New Year Dave Wa3gin ?
-- don??? va3drl |
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Haha, I wondered about both and not worried about it!?I hate GFIs and all the other?rip-offs EATON?and HomeDespot have devised to extract my money from my pocket.? I'm trying to adapt to having pink cerromax in the ham shack! ? Ungrounded two-prong outlets are typically only found in older homes.?Since 1962, the National Electric Code (NEC) has prohibited them in new construction?to minimize the risk of electric shock and electrical equipment damage.? I'd bet Hallicrafters had the design for the SR-150 on the drawing board long before 1962.? Best, dave wa3gin On Tue, Dec 31, 2024 at 9:56?PM don Root via <drootofallevil=[email protected]> wrote:
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开云体育Hi dave? ya it seems the Sr-150 was made from 1961? to 63? so designed just before polarized outlets were required. I have used GFCIs for years especially for power tools and especially outdoors or in the basement. Once I thought a GFCI on an “extension cord ”? was tripping with a kettle as a load and thought the GFCI was bad, so I plugged the kettle directly into the wall and it blew a big hole in the enamel of the stove.? The wire in the kettle was running along the bottom and had melted the insulation. Ohh I recall in 1966 we used lots of cheaters in the plant when all the [new] scopes suddenly came with 3 prong plugs, and the plant was old. ? From: [email protected] [mailto:[email protected]] On Behalf Of Dave Jordan via groups.io
Sent: Tuesday, December 31, 2024 10:35 PM To: [email protected] Subject: Re: [HallicraftersRadios] SR-150 PWR Supply ? Haha, I wondered about both and not worried about it!?I hate GFIs and all the other?rip-offs EATON?and HomeDespot have devised to extract my money from my pocket.? I'm trying to adapt to having pink cerromax in the ham shack! ? Ungrounded two-prong outlets are typically only found in older homes.?Since 1962, the National Electric Code (NEC) has prohibited them in new construction?to minimize the risk of electric shock and electrical equipment damage.? ? I'd bet Hallicrafters had the design for the SR-150 on the drawing board long before 1962.? ? Best, dave wa3gin ? ? ?
-- don??? va3drl |
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Thanks, I can make the power supply the common point ground or run a ground from both radio?and power supply to the operating table ground buss. I don't expect to have 60hz AC and if so I'll rework the mic audio circuit, not the chassis earth ground.? The breaker panel is less than 4ft away and the operating position ground buss bar is tied to the breaker panel ground whose ground rod is less than 6ft away.? In the SR-2000 the mic audio is a straight run to the audio tube. Not sure if the shielded mic line is grounded at the mic jack or not but hum is easy enough to remedy if it pops up... Lots of fun in 2025. 73 dave wa3gin On Wed, Jan 1, 2025 at 11:30?AM Jack Brabham - KZ5A via <kz5a.jack=[email protected]> wrote:
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Jack I seem to have missed the comment by Walter Cates on 60 cycle hum on TX.? Can you tell me the message date or message number so that I can refresh my memory? If the GFCI is tripping then there is an imbalance of current between the common and hot leads of the line cord.? The GFCI is doing it's job in detecting this imbalance.? There is a leakage path there, possibly through the station ground? Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Wednesday, January 1, 2025 at 10:30:56 AM CST, Jack Brabham - KZ5A via groups.io <kz5a.jack@...> wrote:
I just finished a complete rebuild on my? PS 150-120.? I choose to stay with a 2 prong polarized power cord mostly due to Walter Cates recommendation to avoid 60hz hum on the TX.? ?Didn't see why at first but I think I've codgertated it out.? ?The TRX? and PS were designed together and? the TX is intended to be the common signal ground point for both.? With? a 2? prong polarized plug and cord this works fine but will not support a GFI.? ?
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If you add? a? 3 prong? cord to? the PS the 60hz current passed? by C201 and C202 appears on the electrical Ground and can be passed to the electrical Common via the main AC breaker box? where the 2 are terminated to the same buss.? ?This can appear as a 60hz potential between a station RF ground and the electrical Common which apparently can find it's way into the TX audio.
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This is no doubt highly situational depending? on house and station wiring.? ?If you use a 3 prong AC cord and encounter the hum, deleting C201 and C202 might fix it.? Also the 60hz current passed onto the electrical Ground by the capacitors? could? trip a GFI considering that is the current they are intended to sense.??
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A ferrite on the power cord can functionally? replace? the caps.
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73 Jack KZ5A
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If the GFCI disconnects a radio or similar appliance from the AC line voltage then there is a problem with a leakage current that is forming an alternate path for the line current.? A properly working GFCI will trip when there is approximately a 5 mA difference between the current carried in the "hot" conductor and the current carried in the "neutral" conductor.?? Any capacitor connected between either the hot, common or both to the chassis in the radio should be sized so that the maximum current allowed to flow is below the 5 mA trip point of the GFCI.? In every radio I have worked on that tripped a GFCI, I found a faulty AC line bypass capacitor.? I suppose a faulty power transformer would also do the same thing but I guess I have been lucky in that the leakage was always caused by a faulty AC line to chassis bypass capacitor. In and earlier post I said that the GFCI trip current was 15 mA but my memory was in error, it is actually around 5 mA.? It seems that 1 mA is the tingle threshold of feeling the flow of current for the average person.? Above 5 mA is a painful feeling and above 25 mA is the loss of muscle control.? Above 50 mA there is a real problem.? See:?? My understanding of the NEC is that the third conductor, ground, is not supposed to carry any current so there is no voltage drop in this wire.? The neutral conductor and the ground conductor are bonded together at the distribution panel.? As to where the NEC code ends, some professional electricians say at the outlet, others say beyond and into the equipment plugged into the outlet.? The answer to this is beyond my understanding if the professionals cannot agree!?? But I do think that the Underwriters Laboratory (UL) is the agency that issues the requirements and does the testing for appliances plugged into an outlet.? If the radio has received the UL label, then it has met the UL requirements at the time it was tested.? Of course I understand that those requirements have changed over time.?? I do not know if the UL has changed it's position on switching the neutral line as was done in AA5 radios.? AFAIK the AA5 was designed as an insulated appliance with the outside cabinet shielding anyone from contact with a hot chassis.? Any shock that one gets from touching an antenna or other terminal is caused by the AC line to chassis bypass capacitor.? Below 5 mA is a nuisance but not lethal as is suggested by at least one sensationally done YouTube video. Using a polarized plug will guarantee that the AA5 chassis will be at or near ground potential, assuming that the outlet was properly installed.? In researching this note, I found that AI is mistaken when it mentions the date of 1962 for when the polarized plug was developed.? Per????The following was found: "Many of the safety requirements for extension cords predate the existence of the CPSC, (Consumer Product Safety Commission).? For example, CPSC staff believes that UL incorporated requirements for polarized (and grounded) plugs and receptacles on cord sets around 1962.? A search by CPSC staff found that grounded plugs were developed as early as 1911, and polarized plugs became available in 1914.? The National Electrical Code (“NEC”) adopted requirements for polarized electrical outlets in 1948 and for grounded 120-volt receptacles in 1962.? Since 1987, UL 817 has addressed the identified, readily observable characteristics that are included in the rule (minimum wire size, sufficient strain relief, proper polarization, proper continuity, outlet covers for indoor cords, and jacketed cords for outdoor extension cords). Just another opinion, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Tuesday, December 31, 2024 at 09:35:36 PM CST, Dave Jordan via groups.io <wa3gin@...> wrote:
Haha, I wondered about both and not worried about it!?I hate GFIs and all the other?rip-offs EATON?and HomeDespot have devised to extract my money from my pocket.? I'm trying to adapt to having pink cerromax in the ham shack! ? Ungrounded two-prong outlets are typically only found in older homes.?Since 1962, the National Electric Code (NEC) has prohibited them in new construction?to minimize the risk of electric shock and electrical equipment damage.? I'd bet Hallicrafters had the design for the SR-150 on the drawing board long before 1962.? Best, dave wa3gin On Tue, Dec 31, 2024 at 9:56?PM don Root via <drootofallevil=[email protected]> wrote:
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Dave Jordan
don Root
Jim Whartenby