1935 GE Model A-53 AM/SW Tombstone Radio

[vortalexfan]

Originally Posted by Electronic M

Just because you paid a lot for a power supply doesn't mean you're not buying a cheap crappy one with a highway robbery markup... Overpriced crap exists in every market.

I'm going to go to the local computer store and see what they have as far as a computer power supplies go.

[vortalexfan]

OK So I managed to pick up at a local computer store a 700W EVGA Branded power supply for $85 and I Installed it in my computer and its dead silent as far as EMI/RFI noise goes.

Unfortunately my housemate's power supply is still as mean, nasty and noisy as ever.

In fact, I took my recently acquired Sony AM only transistor radio around the house and I figured out (and I should of figured it out sooner) that my Housemate's computer power supply is using the whole house's wiring system as a giant antenna (think of those old capacitive coupled FM Antennas from back in the day that used to use the whole house wiring system as a giant FM Dipole Antenna) and so the EMI/RFI noise being emitted by my housemate's computer power supply is being radiated all throughout the house via the house's old ungrounded romex wiring (yes you heard that right UNGROUNDED romex wiring).

The fact that this house is still utilizing its original 90+ year old ungrounded romex wiring that is being concealed with modern grounded outlets (that are actually ungrounded clear back to the breaker box) that is why the my radios are affected by EMI/RFI noise so easily, including battery sets, because the
el cheapo computer power supplies are acting like a small radio transmitter of sorts and radiating a "radio signal" all through out the house with the ungrounded wiring acting as an "antenna" of sorts.

[dieseljeep]

Originally Posted by vortalexfan

OK So I managed to pick up at a local computer store a 700W EVGA Branded power supply for $85 and I Installed it in my computer and its dead silent as far as EMI/RFI noise goes.

Unfortunately my housemate's power supply is still as mean, nasty and noisy as ever.

In fact, I took my recently acquired Sony AM only transistor radio around the house and I figured out (and I should of figured it out sooner) that my Housemate's computer power supply is using the whole house's wiring system as a giant antenna (think of those old capacitive coupled FM Antennas from back in the day that used to use the whole house wiring system as a giant FM Dipole Antenna) and so the EMI/RFI noise being emitted by my housemate's computer power supply is being radiated all throughout the house via the house's old ungrounded romex wiring (yes you heard that right UNGROUNDED romex wiring).

The fact that this house is still utilizing its original 90+ year old ungrounded romex wiring that is being concealed with modern grounded outlets (that are actually ungrounded clear back to the breaker box) that is why the my radios are affected by EMI/RFI noise so easily, including battery sets, because the
el cheapo computer power supplies are acting like a small radio transmitter of sorts and radiating a "radio signal" all through out the house with the ungrounded wiring acting as an "antenna" of sorts.

I don't know if Romex was around 90 years ago. The house might be wired in BX cable. BX has been around since the early 20's. It has a flexible steel armor.
Anyway, it's a code violation to install a grounding receptacle to replace a non grounding receptacle, unless it can be effectively grounded.
Some shady electricians tie the neutral conductor to the ground terminal to appear that the receptacle is grounded.

[vortalexfan]

Originally Posted by dieseljeep

I don't know if Romex was around 90 years ago. The house might be wired in BX cable. BX has been around since the early 20's. It has a flexible steel armor.
Anyway, it's a code violation to install a grounding receptacle to replace a non grounding receptacle, unless it can be effectively grounded.
Some shady electricians tie the neutral conductor to the ground terminal to appear that the receptacle is grounded.

I'm sure its Romex, very early Romex, its got a black cloth outer sheathing and then 2 inner rubber insulated solid copper conductors (black and white respectively for hot and neutral), no grounding conductors present whatsoever.

My guess is that the lack of a grounding conductor at the box and going elsewhere in the house is why there's so much RFI/EMI Noise radiating throughout the house from my housemate's computer power supply.

My landlord when he bought this house for his son (my housemate) he had the house completely gutted supposedly and redone, which when they did that, I'm kind of surprised that he didn't have the place wired up to code, but he didn't I think he just more or less just "put lipstick on the pig" so to speak and called it good enough.

In other words he left the old ungrounded wiring in place and put grounded outlets into place to hide the fact that there was no grounded wiring in place and just went from there.

I'm actually surprised this place passed inspection with as many corners as they cut.

I can get a picture of the old wiring for you so you can see what it is that's in my house.

[Electronic M]

I've only seen 2 conductor Romex in use once. The old family cabin used black plastic 2 wire Romex to connect the outhouse (2 light sockets and an outlet) to the main building....the Romex was strung overhead from tree to tree. This was done sometime in the mid 60s-mid 70's when electricity became available there.

[vortalexfan]

Originally Posted by Electronic M

I've only seen 2 conductor Romex in use once. The old family cabin used black plastic 2 wire Romex to connect the outhouse (2 light sockets and an outlet) to the main building....the Romex was strung overhead from tree to tree. This was done sometime in the mid 60s-mid 70's when electricity became available there.

OK I figured out what is in my house, its first generation Non-Metallic Sheathed Wiring, aka Romex like I was stating before, the stuff in my place uses a rubberized cloth outer sheathing and rubber insulated solid copper conductors, from what I was reading that kind of wiring only had a 25 year life expectancy and should be updated, unfortunately whenever I've pointed that out to my landlord he brushes it off.

Anyways the way this house is currently wired up, they have a mixture of original wirirng and modern wiring (where they spliced modern wiring into old wiring to extend or add to a circuit) and they installed modern grounded outlets and switches without any actual ground wires to speak of to hook to the aforementioned grounded outlets and switches, they even have several 10 amp breakers running 2 rooms worth of outlets which makes it difficult to run anything like a vacuum without popping a breaker.

That's just to give you an idea of what i have to work with in my house, wiring wise, unfortunately its not my place, I'm just a renter so I can't do anything about the wiring in the house.

See pictures below.

[dieseljeep]

Originally Posted by vortalexfan

OK I figured out what is in my house, its first generation Non-Metallic Sheathed Wiring, aka Romex like I was stating before, the stuff in my place uses a rubberized cloth outer sheathing and rubber insulated solid copper conductors, from what I was reading that kind of wiring only had a 25 year life expectancy and should be updated, unfortunately whenever I've pointed that out to my landlord he brushes it off.

Anyways the way this house is currently wired up, they have a mixture of original wirirng and modern wiring (where they spliced modern wiring into old wiring to extend or add to a circuit) and they installed modern grounded outlets and switches without any actual ground wires to speak of to hook to the aforementioned grounded outlets and switches, they even have several 10 amp breakers running 2 rooms worth of outlets which makes it difficult to run anything like a vacuum without popping a breaker.

That's just to give you an idea of what i have to work with in my house, wiring wise, unfortunately its not my place, I'm just a renter so I can't do anything about the wiring in the house.

See pictures below.

Not too much pride in workmanship shown there!
Pex water lines, mixed with rigid plastic lines.
If the owner decides to sell this home later, a home inspector is going to cite all the faults.
Are you sure about the breaker rating? 15 amp is the smallest rating for a #14 wire.

[jr_tech]

Interesting history of wiring practice in the US:

https://wenatcheehomeinspection.com/..._the_USA-1.pdf

From above source:

“Nonmetallic Cable
Although nonmetallic-sheathed cable, or NM for short, was first listed and described in the NEC in 1926, it was actually invented a few years earlier by General Cable at their Rome Wire Division in Rome, NY, and marketed under the trade name “Romex®.” Today many installers still refer generically to NM cable as Romex. Early NM cable had their individual conductors jacket wrapped in a cotton braid that was impregnated with either a varnish or tar-like substance for moisture protection.
Around 1950, synthetic spun rayon was being permitted to replace the cotton thread in the jacket braid. Then in the early 1960’s, thermoplastic began replacing the braided jacket altogether, and by about 1970, most all NM cable had a PVC outer jacket, even though a braid was still permitted until 1984. Also in 1984, NM-B cable was developed and required to have 90°C rated individual conductors, and a 75°C outer jacket (see Fig. 4).
Until the early 1960’s, most NM cable for residential use did not have a grounding conductor. However, changes in the 1962 Code that mandated equipment grounding for all branch circuits popularized the use of NM cable with ground. Earlier versions of NM cable with ground permitted the grounding conductor to be No. 16 AWG for 14 and 12 gauge copper NM, and No. 14 AWG ground for 10 gauge copper NM. In 1969, new requirements no longer permitted an undersized grounding conductor for 14, 12 and 10 gauge NM cable.”

jr

[dieseljeep]

Originally Posted by jr_tech

Interesting history of wiring practice in the US:

https://wenatcheehomeinspection.com/..._the_USA-1.pdf

From above source:

“Nonmetallic Cable
Although nonmetallic-sheathed cable, or NM for short, was first listed and described in the NEC in 1926, it was actually invented a few years earlier by General Cable at their Rome Wire Division in Rome, NY, and marketed under the trade name “Romex®.” Today many installers still refer generically to NM cable as Romex. Early NM cable had their individual conductors jacket wrapped in a cotton braid that was impregnated with either a varnish or tar-like substance for moisture protection.
Around 1950, synthetic spun rayon was being permitted to replace the cotton thread in the jacket braid. Then in the early 1960’s, thermoplastic began replacing the braided jacket altogether, and by about 1970, most all NM cable had a PVC outer jacket, even though a braid was still permitted until 1984. Also in 1984, NM-B cable was developed and required to have 90°C rated individual conductors, and a 75°C outer jacket (see Fig. 4).
Until the early 1960’s, most NM cable for residential use did not have a grounding conductor. However, changes in the 1962 Code that mandated equipment grounding for all branch circuits popularized the use of NM cable with ground. Earlier versions of NM cable with ground permitted the grounding conductor to be No. 16 AWG for 14 and 12 gauge copper NM, and No. 14 AWG ground for 10 gauge copper NM. In 1969, new requirements no longer permitted an undersized grounding conductor for 14, 12 and 10 gauge NM cable.”

jr

It's a very informative website!
I not that familiar with Romex wiring after living in Milwaukee, county Wisconsin for 58 years. Romex was not allowed until the mid 70's.
I lived in three different old houses that were wired for electricity many years after they were built. They were wired in the mid 20's and it was all BX cable.
It was my understanding that the Electric Company subsidized the installation.

[vortalexfan]

Originally Posted by dieseljeep

Not too much pride in workmanship shown there!
Pex water lines, mixed with rigid plastic lines.
If the owner decides to sell this home later, a home inspector is going to cite all the faults.
Are you sure about the breaker rating? 15 amp is the smallest rating for a #14 wire.

Yes, I'm sure, I know what I saw.

I was running some space heaters (oil filled radiators) one winter because my side of the house which used to be the garage that the previous owners of the place had converted it into additional living space, and so when they did it, they didn't do it correctly including the HVAC runs and insulation.

So my side of the house even with the heat cranked up wouldn't get above 55 degrees in the winter without the use of a space heater or two.

Unfortunately the breaker blew whenever I had the spaceheater(s) set on high and when I looked at the breaker that controlled the outlets that were in my office and bedroom (one half of my bedroom and one half of my office) I saw that the breaker was only rated for 10 amps.

When I pointed it out to my landlord he had an electrician come over and the electrician said that the 10 amp breaker was all that could be used on that circuit because of the size of wire that was being used (18AWG) which is the size of wire you would normally use to wire up a table lamp or an old radio but not to wire up several sets of outlets...

The odd thing is that the rest of the breakers in the house that are associated with several runs of outlets are 20 amp breakers.

Also another odd thing is that the only place where there's GFCI Outlets are in the bathrooms, they don't have any GFCIs in the Kitchen anywhere, which AFAIK NEC calls for GFCIs wherever you have outlets near a water source (e.g. a sink) that includes the kitchen.

So unfortunately there were lots of corners cut in this house, and part of the reason for that is because my landlord (my housemate's dad) is a cheapskate and always tries to get things done as cheaply as possible even if it means using repair guys that have questionable credentials in order to save a few bucks.

[vortalexfan]

OK so a little update on this Radio, I think I may have figured out where the hum is coming from in this radio... The original speaker is where the hum is coming from, because the guy I bought this radio originally had a second radio just like this that he gave me to use for parts to get the one I bought from him up and running, and when I used the speaker from the parts unit on the radio, there was no hum to be heard, but as soon as I hooked it back up to the speaker, the hum came back!

So I'm wondering if the filter choke (L15) which is the coil that is in the back of the speaker assembly (see picture below) is bad?

Would a bad filter choke cause the kind of hum that I've been describing that I've been having issues with on this radio?

[Electronic M]

It's possible. If you have swapped a second identical speaker and observed normal hum free opperation (which is what I think I read in your post) then you have confirmed something is not right with the first speaker.

What I would be looking at is the HUM BUCKING coil in the problem speaker. A large portion of electrodynamic (field coil type) speakers place a hum bucking coil in series with a lead of the voice coil. The hum bucking coil is typically a few turns on the same coil form as the field coil. The hum bucking coil acts like a secondary winding on a transformer formed by it and the field coil. The hum bucking coil picks up the AC hum in the field coil and feeds it into the voice coil 180 degrees out of phase. Ideally if the hum bucking has correct phase and amplitude it will perfectly cancell out any hum from the field coil so it doesn't produce audible sound.

If the hum bucking coil is connected with reverse phasing (read that polarity) instead of cancelling the hum it will double the hum (double the hum that would be there if you shorted the hum bucking coil or removed it from circuit which it's self would be worse hum than if the coil was working properly).

Also if the hum bucking coil, the voice coil or the audio output transformer secondary short to ground or B+ it could mess with hum bucking coil opperation.

[vortalexfan]

Originally Posted by Electronic M

It's possible. If you have swapped a second identical speaker and observed normal hum free opperation (which is what I think I read in your post) then you have confirmed something is not right with the first speaker.

What I would be looking at is the HUM BUCKING coil in the problem speaker. A large portion of electrodynamic (field coil type) speakers place a hum bucking coil in series with a lead of the voice coil. The hum bucking coil is typically a few turns on the same coil form as the field coil. The hum bucking coil acts like a secondary winding on a transformer formed by it and the field coil. The hum bucking coil picks up the AC hum in the field coil and feeds it into the voice coil 180 degrees out of phase. Ideally if the hum bucking has correct phase and amplitude it will perfectly cancell out any hum from the field coil so it doesn't produce audible sound.

If the hum bucking coil is connected with reverse phasing (read that polarity) instead of cancelling the hum it will double the hum (double the hum that would be there if you shorted the hum bucking coil or removed it from circuit which it's self would be worse hum than if the coil was working properly).

Also if the hum bucking coil, the voice coil or the audio output transformer secondary short to ground or B+ it could mess with hum bucking coil opperation.

Could it be possible for the speaker to be hooked up incorrectly?

The reason I ask is that the connection plug on the speaker where the speaker plug from the radio chassis plugs into doesn't really have any keying so the plug can go in any way you want (it's a 5 pin plug but only 4 of the pins are actually used) and there really aren't any markings to show which wires are what, and also the color of the wires are faded so badly that you can't tell which color is which on the wires.

[Electronic M]

If it uses the same 30s 5-pin socket/base as a type 76 tube (common speaker plug into the octal era) then it is in a way keyed such that it only plugs in one way. There's 4 pins closely clustered and a 5th pin off a ways....pin spacing is not symmetrical in both axes so it will only plug in one way (unless you break it).

[vortalexfan]

Originally Posted by Electronic M

If it uses the same 30s 5-pin socket/base as a type 76 tube (common speaker plug into the octal era) then it is in a way keyed such that it only plugs in one way. There's 4 pins closely clustered and a 5th pin off a ways....pin spacing is not symmetrical in both axes so it will only plug in one way (unless you break it).

Well that's the thing the plug coming out of the radio itself is broken, it's broken on one of the sides that has the close together pins.

But I think though that more than likely it's the hum bucking coil, that's bad, like I already suggested, I was just throwing that out there as an alternative idea.