Mid twentieth century wiring - relays

I know of 2 houses in the area that use the relay system. Both owners have replaced relays over the years. They both had to remove the current one,take it to an electrical contractor and have them look it up either online or in a catalog

Apparently they are still available but I have no idea what they cost
 
The only relay system I ever saw used a common panel to hold several relays. I think it was in the back of a closet. Are the relay noises coming from different locations for different fixtures, or from a common direction? Any chance someone covered over a panel?
 
If you use the low voltage tone generator to locate wires make sure the power is off. They work good to locate wires.
 
A standard circuit tracer would get you to either the relay or the transformer. If the former, you're done. If the latter, you probably will need access to the secondary anyway so you can inject a signal into the secondary circuit.

Here's another thought. You know what lights aren't working so inject the signal into the other side. Use one of those screw-in AC outlet thingies for that.
 
homebrewed said:
A standard circuit tracer would get you to either the relay or the transformer. If the former, you're done. If the latter, you probably will need access to the secondary anyway so you can inject a signal into the secondary circuit.

Here's another thought. You know what lights aren't working so inject the signal into the other side. Use one of those screw-in AC outlet thingies for that.
Click to expand...
Got a picture of said thingy? You mean a two prong outlet screw in adapter to an Edison bulb socket? Might have one of those somewhere in my house. Still need one of those injector gizmos. Need to get more serious about this - I want to get rid of the house before it drives me into the poorhouse. The taxes and insurance are ridiculously high.
 
This. Or its equivalent.

A sine-wave generator and a coupling cap to keep 110VAC @60Hz at bay could serve to inject the signal. The receiver would be the issue. But I bet there's a DIY version out there.

Just living up to my handle :big grin:
 
I found this youtube that shows a very simple 3-transistor circuit for tracing AC lines in walls. The video starts out about as basic as you can get, just skip past the dumb stuff to the schematic and showing its operation. Basically a capacitively-coupled 3-transistor Darlington running an LED. So this one is passive, in that it's just listening for 60Hz. That would be OK for the circuit that drives the relay coil (or up to the transformer, if there IS one). Tracing the circuit on the other side of the relay with this would require running some live AC up to that screw-in adapter, but runs the risk of connecting the hot side to the local ground.

Another approach I found used a simple AM-band oscillator modulated at around 350Hz with a 555 astable oscillator, here. That way you can use an off-the-shelf AM receiver. It uses some parts your average machinist won't have, but, knowing you, you may....or something equivalent. A simple ring oscillator built with CMOS or TTL inverters would do the job, and probably would be the first thing I'd try. Probably not too stable w/respect to temperature or supply voltage but for down & dirty...

Finally, off-the-shelf circuit tracers seem to be pretty cheap, enough so that they likely can be found in one of those big-box stores. It all depends on how much time you want to spend vs. money you want to spend.
 
homebrewed said:
This. Or its equivalent.

A sine-wave generator and a coupling cap to keep 110VAC @60Hz at bay could serve to inject the signal. The receiver would be the issue. But I bet there's a DIY version out there.

Just living up to my handle :big grin:
Click to expand...
I have to laugh at the link. That ground is guaranteed to be no good. There's no guaranteed ground at normal bulbs, only hot and neutral. Neutral should be connected to ground but it's not an earth connection.

Some AM signal might be good. Then I could use an old AM radio - that's if I can get it in band.
 
homebrewed said:
I found this youtube that shows a very simple 3-transistor circuit for tracing AC lines in walls. The video starts out about as basic as you can get, just skip past the dumb stuff to the schematic and showing its operation. Basically a capacitively-coupled 3-transistor Darlington running an LED. So this one is passive, in that it's just listening for 60Hz. That would be OK for the circuit that drives the relay coil (or up to the transformer, if there IS one). Tracing the circuit on the other side of the relay with this would require running some live AC up to that screw-in adapter, but runs the risk of connecting the hot side to the local ground.

Another approach I found used a simple AM-band oscillator modulated at around 350Hz with a 555 astable oscillator, here. That way you can use an off-the-shelf AM receiver. It uses some parts your average machinist won't have, but, knowing you, you may....or something equivalent. A simple ring oscillator built with CMOS or TTL inverters would do the job, and probably would be the first thing I'd try. Probably not too stable w/respect to temperature or supply voltage but for down & dirty...

Finally, off-the-shelf circuit tracers seem to be pretty cheap, enough so that they likely can be found in one of those big-box stores. It all depends on how much time you want to spend vs. money you want to spend.
Click to expand...
Good ideas. Maybe I can cobble something up. Been a while since I've played with stuff like that.

Jeepers, I just got another teardown offer for the house, makes me sad. Cash, but well under FMV. Damn speculators.
 
If that's what the market is offering then maybe it makes more sense to tear it down yourself and let the speculators bid up the land.

It's hard to see something that was such a big part of your life just torn down and replaced, but if you are responsible to the estate you will need to do what makes the best return in the time allowed.

Where I live it's almost a given that anything built in that time period will be torn down, things were very different back then and what buyers are demanding now won't cut it.

If I were in your position I'd have a very frank discussion with a realtor about the actual chances of getting more for the house intact vs. your current offers. If the value of a custom home in the area is high enough, and you have the stomach for it, working with a developer to build for the current market might be the best return. Those speculators probably aren't guessing that there's a profit to be made and if they can do it you could too.

I have a guy that works for me recently sell his property to a speculator, it tore him up as it was where he and his late wife lived for 20+ years. The house was severely damaged by a tree falling on it and repairs to current code would be excessive. At the end of the day though he didn't have the will, or the cash to see a rebuild through and selling it as is was the best call.

Chances are the lighting issue you're trying to address is just one item on a long list that any potential buyer would want addressed if they were going to live there. It's tearing my wife up to see our Michigan home being torn apart by the new owners, 1882 brick Victorian that had original windows, but ultimately it's theirs now so they can do what they want.

Go to a few open houses in the neighborhood and you'll know if yours would ever be more than a tear down....

john
 
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