Hi,

Have installed a new wired doorbell. (DESA) Heath/Zenith Model #LE-65-B. (Electronic)

I also changed and added a new 16 Volt Xfrmer and a lighted pushbutton and a diode.

After install, all worked fine including the "Lighted" pushbutton.

I checked the bell a few hours later, it stopped working and the pushbutton light was off.

I went to the Xfrmer and checked the voltage with a test light and it was OK.

Then I looked at the push button and it was on again and all worked for a little while,

Then off again.

I took the button apart and disconnected the bulb and all worked:mad: again.

Isn't there a way to wire this with a lighted push button?

Add a resistor perhaps?

Thank you

Just thinking??

Do they make a Double pole door bell push button?

I think that would solve the problem for some.

You could run a separate Xfrm to the push button and light up the button.

Just an idea.

Thanks

Wouldn't use a diode, a resistor may work, I have seen the resistance of the bulb be too low
To open circuit fully, On some things I have had to remove the bulb. You need to see why power is restoring itself.
I would Hook back up, when light goes out, turn off breaker for door bell, wait a minute, then turn back on. See if it comes back, want to be sure no intermittent connection when checking wiring/voltage.
What is the VA of the Transformer, and is that what it requires.

Hi,

Thank you - what size (Ohms) resistor??

You will have to experiment, Too low, it will have same effect, too high, chime won't work.
VA of XFMR?
Why were you losing power? Does transformer reset itself?

Hi,

I'm trying your suggestion - have reinstalled everything, including the diode and all is working, for the last half hour.

I did re-tighten and check all my connections.

My Xformer VAC is 15 and the voltage is 16 volts.

I tried a few resistors and N.G. ohms are too high. As I dumped my resistor supply a few years ago :) suggest a starting point for the OHMS.

I don't want to buy a million resistors to get to the correct ohms...

Where do I start?? 50 Ohms??

Thanks

I am rewriting this as somehow it did not post.
I would get a package of 33 ohm ressistors(5), then try in series, then parallel.
2 in parallel is 16.5 ohms, 4 in parallel is 8.25 ohms.
2 in series is 66 ohms.
I don't think I would use the diode.

Hi,

Just bought some resistors as well as a "Pot"

I just checked the bell and it's off again... Shut the breaker off for 30 Sec. and all
Is working again.

Looks like the wires are OK, no breaks

Will advise.

Thank you

Hi,

By the way, there does not seem to be a thermal couple/breaker within the Xformer

Thanks

Hi,

Just got finisher trying resistors w/o any luck.. Seems that if I go up 10 Ohms it changes from Not working to pulsing..

I disconnected the bulb, added the diode and put it together. We'll see if it keeps going.

I still like my idea of a DPST push button lighted switch with a separate Xformer for the light.

In my case I would need to rewire, as the wire now only has two conductors and it goes

Up into a vaulted ceiling.

My wife wouldn't like me making holes in the ceiling!!

Thanks again.

What you can do is to take a standardlighted doorbell and take it apart.

Inside, add a diode/resistor and LED (probably surface mount). The resistor should be about 24/24e-3 or slightly smaller.

These components are mounted inside the pushbutton. Parts can be ordered from DigiKey Corp. | Electronic Components Distributor | United States Home Page (http://www.digi-key.com) .

I've done it, and it's been working nearly forever.

I don't know what happened to my post.

What you can do is get a lighted push button and disassemble it.

Inside place a surface mount LED, a resistor and a diode all in series, the correct way of course.

The resistor should be about 24/10e-3 ohms or a little less.

Fit this inside the doorbell between the two contacts and it will work nearly forever. That's what I did.

Hi,

Thank you. I clicked on the link and searched for LED's - no luck.

Am I doing something wrong?

Also can you tell me what you mean by 24/10e?? Also adding a resistor - LED and a diode the Correct way... What's the correct way?

How about a diagram, if possible.

I know what 3 ohms means, but not the above.

Thanks again

This will not be the final components, but it will give you an idea of the circuit and you will know if it works by trying it.

What I'd like you to do is to go to Radio Shack and get an LED with Leads. Pick a color. I used green

10e-3 is 1x10-3 or 0.010 amps or 10 milliamps; Typical trive currents are between 10 and 50 mA. I'd use 0.020.

The resistor actually is calculated by( 24-1.2-0.6)/0.020 The 1.2 is the forward drop of the LED and the 0.6 is the drop of the extra diode. That's 1110 ohms. 1000 ohms is a standard value.
You can re-compute I and use below, but it won't make much of a difference.

You can find P ~ (0.020)^2*1000. That's 0.4 watts, so a 1/2 watt resistor is needed.

Get a 1n4001 or 1n4002 diode. You will notice a band on the diode and you'll notice a cut off flat on the led.

Wire the flats and the band in the same direction.

If that works, I can find you appropriate parts to make a lighted doorbell.

Then try to find a lighted doorbell that you can unassemble and put back together.

This circuit is big, but we can make it smaller.

Hi,

Thanks again.. I'll go tomorrow for the parts.

How are these 3 parts wired in "Parallel" or what?

Thanks

Also,

I have a diode that came with the doorbell will that do?

Thanks

They are wired in series in any order. If the LED doesn't light, reverse the diode.

What is the number on the diode?

If you'd like, I can take pic of mine?

If the above circuit doesn't work, we can make either work with a 24 VAC relay.

The lamps burn out, the LED's do not.

Hi,

Not sure of the diode number, I'll buy the one you selected in your previous post
From Radio Shack as I have to go there anyway.

Thanks

Here is an example surface mount LED. See the dimensions page.
Probably can support it with 1 diode and 1 resistor on either side.

Here is one such modification:

LED DIY Doorbell Modification (http://www.jlightning.com/files/doorbell/index.html)

My button was much smaller. It was one of those recessed into the wall. Only about 5/8" round.

Hi,

Looking at your pictures I do not see the diode, only the two LED's and the resistor.

I know you said put the Resistor,LED and Diode in series, how are two LED's wired into the circuit?

The LED or LED's are used in place of the original bulb?

Please draw a schematic with one, then two, LED's, if possible.

Thank you, sorry to be a pain!

Hi,

Picked up the parts today.. Only thing, I found the LED's are FW Current: 70ma

and FW supply 2.6 Typical and 3.3V max.. These are 4 pin LED's

I'm thinking I might have gotten the wrong LED's?

Will these LED's change the resistance value of the resistor form 1K?

Thank you

What Radio Shack Part number did you get for the LED's?

Did yoy get this? 20mA 4-pin 130° Power LED (White) - RadioShack.com (http://www.radioshack.com/product/index.jsp?productId=3060973&tab=summary)

Of course Radios Shack info isn't there and probably each pair of the pins is connected to Anode(+) or cathode(-). The cathode side of the diode is the side with the band.

So it's something like this:

*---- 1K ******- LED +*****-diode+*******

LED's are a diode, so they rectify. The added diode is protection when operating the LED off AC.

If you were going to use two, you could add an LED in series or make another string like the above, but put it backwards in the circuit. Then you have one led powering from each side of the AC line.

You should also be able to put the LED's back to back in the circuit too if using two.

At this point, all I wanted you to do do, was to get a feel and to see if it could work. We don't know what the input circuit looks like in the bell chime. It's not a coil of wire, so lighted doorbells have a poor chance of working.

Aside:
If you got a 24 VAC relay and wired the doorbell, lighted or other wise, such that when you pushed the button, the relay coil closed you have what it takes to make a lighted doorbell work.

Now, you take the normally open contacts of the relay and put it where the pushbutton was. ---> instant lighted doorbel.

Hi,

Put the parts together on the bench today with an extra Xfrmer and both LED's
Are working together.

Will put the test package onto the push button and test soon, will advise

Thank you.

Hi,

Posted my last before I read yours.. No I didn't get the Radio Shack white ones
Mine are red and FW 70MA..

Is this too much of a draw?

Thanks

Your limiting the brightness by the resistor. The spec for most led's is about 10 mA to about 50 mA with a design goal of about 20 mA. The lower the current, the longer lifetime. The higher the current, the brighter and shorter lifetime.

Kind of an oops, but you can use 16V for the volatage. I think I usd 24 without thinking. The LED's only see a half cycle anyway.

Remember, you don't have to cram everything in. Just externally connect your series combination thingy to the button and see if it works.

You may decide on both; LED button and the relay modification.

Hi,

I just tried both LEDs one for each side of the AC cycle on my test xformer.

I will try the basic (One LED) for real when my wife wakes up from her nap.

I don't want to ring the bell with her asleep!!

Would this type of setup work with a push button for a garage door opener?

I've tried a lighted push button for my garage but it ony worked for a short while
Then had trouble getting it to work. Had to hold and reset the push button.

After cutting out the push button bulb everything worked again.

I haven't checked the voltage for the garage door - don't know if AC or DC?

Thanks

Measure the voltage across the switch contacts and dermine if it is AC or DC?

If you have a current range on your meter, use something like the 300 mA scale and put the meter in series with the button and measure the current.

Open circuit voltage and short circuit current will give us something to go on.

Otherwise, we have to do the relay trick.

Hi,

Just tested the actual door bell but sadly N.G. with 1K in place, wouldn't complete 8 note chime.

Had to reduced the resistance to 10 ohms and now operating OK..

Will let this run for awhile and recheck. When I tried this with just a diode and the regular bulb in place this worked for a few hours then all went out including the chimes.

I believe the 24VAC relay trick would require 4 wires to the push button, correct?

If so mine only has two and would be a mess to rewire. I'm not sure if the wire is stapled
Anywhere in the walls.

Let you know

Thanks

Something seems fishy. You are attaching that resistor/diode/LED network across a switch that doesn't have a bulb in it, correct? I think you put the combination in series with the button. It's supposed to be across the button.

Therefore, the light/resistor/diode gets shorted out when you push the button.

This doesn't work like a normal circuit.
With a bell, which will act like a piece of wire, a bulb and a transformer as long as the light load is small, then the bell can't ring, but the light will light. When the switch shorts out the light, there is enough current o make the bell ring.

You can try reversing the network across the switch too.

You can measure the open circuit voltage and short circuit current as well.

The relay trick should not require anymore than 2 wires to the bell.

Something seems fishy. You are attaching that resistor/diode/LED network across a switch that doesn't have a bulb in it, correct? I think you put the combination in series with the button. It's supposed to be across the button.

Therefore, the light/resistor/diode gets shorted out when you push the button.

This doesn't work like a normal circuit.
With a bell, which will act like a piece of wire, a bulb and a transformer as long as the light load is small, then the bell can't ring, but the light will light. When the switch shorts out the light, there is enough current o make the bell ring.

You can try reversing the network across the switch too.

You can measure the open circuit voltage and short circuit current as well.

The relay trick should not require anymore than 2 wires to the bell.

Hi,

Checked again, the switch is wired correctly.
The LED - Resistor 10 Ohm - and Diode in series across the push button leads.
All works now.

If I increase the Ohms by even 10 ohms the chime only plays a few notes - doesn't complete.. The original bulb is OUT of the switch circuit completely.

Could there be a problem using the 70ma LED?

Radio shack #276-0020

Thanks

My computer is crippled right now, recently had a hard drive crash and not up to speed yet. I'll try to scribble something and scan it because I still think we are on different pages, even based on your last post.

Hi,

Good luck on your computer.

Measure the voltage with the diode in place, then use this calculator:
LED calculator for single LEDs (http://led.linear1.org/1led.wiz)

Munch on this for a while. I didn't pretty print anything. See if it makes any sense.

Hi,

Thanks, I'm LOOKING!!

Hi,

Here's a simple drawing of my start and how it is now. I used the 70MA LED and a 10 Ohm resister with the diode. It has been working for 10 Hours. The LED is bright - may be too much voltage given the lower resistor.

While looking at your drawing I'm not sure I understand it. Most likely me? Could you explain the new relay and xfrm more. Not sure where it all ties in to my set up hense my drawing.

Thank you

Hi,

I didn't draw or pay attention of the polarity while drawing the pictures.

Good Job.
Measure the voltage across each of the diodes.
Same diodes should read the same, Don't know how much Overvoltage will knock out the led's.

Hi,

Thank you. I'm not sure how long the one LED will last because of the voltage. I was thinking of adding another same circuit with another LED in reverse to get the other half of the AC cycle and hope that the added circuit will reduce the voltage a little on the LED's.
Worth a try.

Not sure if they have higher voltage LED's
I'll take a look at the link KISS sent me.
I do have an electronic outlet not too far from me that I use.

Thanks again.

If the voltage is high at Led, Increasing resistor should fix.
Each led will block each others half cycle. They have to be inline(anode of 1 to cathode of the other). They do make bi colored Leds, which when reversing polarity, it lights the other color(red or green), they also make Tri-Colored Led's red with diode 1 direction, green is with the diode reversed, yellow when AC is present(no diode).
You still only need 2 conductors to doorbell switch.

Here is a 24 VAC relay data sheet: http://relays.tycoelectronics.com/datasheets/KHA_DS.pdf

Note that the coil resistance is 160 ohms.

I'm not addressing the easiest, best, cheapest etc. just a "how to".

24 VAC is standard in the AC world, but it's possible that many other voltages can work. You can even get a 24 VAC wall transformer or a transformer that mounts in a 4 x 4 outlet box.
Sometimes these transformers are designed as "energy limiting" so that the do not require fusing. A shoort will not damage them. So 24 VAC is a common voltage and parts are available for that voltage.

Using DC voltages can meke things more expensive because of contact protection. 24 DC is used in industries because of the ability to back up with simple 12 V batteries in series.

That out of the way.

You will note that you have two wires going over the wall and the "meat" of your doorbell is accessible.

If you cut the wires over the ceiling, this is where the "new circuit" splices in place.

The right pair going to the switch goes to a 24 VAC transformer and the relay coil wired in series. The value of R get's adjusted. 1K is a good place to start.

With just that connected, when you press the button the relay changes state. When the relay is off 24 VAC is supplied through the coil resistance of 160 ohms, the diode, the xtra resstance, the LED and the LED should light. Relays picked correctly, will not have enough current ot "pull in" when the LED is on.

Shorting out the extra resistance with the button will "pull in" the relay".

Pick two terminals of the relay that are open when the pushbutton is off and closed when on and connect it to the left side where your circuit was cut. This is like a switch and therefore the chime rings.

The same system can be extrapolated to work on your garage door.

Hi again,

Just back from my doctors - Lower back pain.. I could be resting for a few days!

Thanks for your help Stratmando and Kiss...

I'll be experminting with this and looking at your diagram, will advise.

By the way - just checked the button lite and bell - all still OK - for now

Thanks

Hope you feel better.

Just to re-iterate again:

You'd be making a simple circuit to close a relay when a push button is pressed. 24 VAC relays are common and 16 VAC ones are not likely to exist. The light across the push button is similar to a "bown fuse indicator". Neon lamps with 100K or so resistors have been used for 120 VAC circuits for a long time.
The relay more close resembles what a bell might look like, a low resistance wire.

So, you'd be replacing the button loop with one of a different voltage (namely 24 VAC).

The doorbell or garage door opener will see an actual switch just like it always did. No new wires are necessary.

Some ways to proceed:
A socketed relay mounted in a case and a 24 VAC wall-wart.

A socketed relay, a 24 VAC xformer, fuse, LED pilot lamp mounted in a case is another. Use either a plug in connector or a couple of terminal strips.

Can also put a 24 CAV xfomer mounted on a 4 x 4 plate (common in AC systems), put a relay in another junction box.

The Cadillac (may be another term now) is of course a NEMA enclosure, DIN rail, DIN rail transformer, DIN rail mounted relay with indicator and check button.

Still a DIN or screw terminal base for a relay would be nice.

All sorts of options.

A "check button" is available with some industrial relays. It allows activation with a momentary mechanical button.

An "indicator light" is just that, an indicator wired in the relay housing.

Again, there are also special purpose relays that can have an AC/DC coil combination. Rare, but useful, but not likely for this application.

Hi,

Thanks aagin for the help.. I'am feeling better. Seems when you get near a doctor everything clears up, just like a car going to a mechanic.

For now I have the new circuit on the project board and remounted on the push button.

One LED - One 10 Ohm resistor and one diode. I did stop back to Radio Shack and
Bought a couple of Green 20ma LED's, made no difference needed 10 ohms.

I'am using one LED now and all working.

I'am still looking at the diagram for the 24VAC system.

Thanks again

I like simple, you have a good solution, if it burns out, slowly increase the resistance.
The bi color led(red and green) can be easily switched from green to red, and back by reversing the diode. If you want to add a DPDT switch with the diode, you can select by the flip of a switch.
It did give me a good Idea to use with the alarm panel, the color of the door bell light will indicate, alarm condition(armed, dissarmed, alarm conditions). This just requires a dpdt relay in alarm panel.

Do me a quick favor and measure the resistance with your ohmmeter.

I'm wondering if your reading the color code of a 5 band resistor.

black brown brown black = 1000 ohms

and

black brown red is 1K when 3 bands

Take a look here at the relays and then click on the socket.

Search Results (http://www.factorymation.com/s.nl?sc=2&category=&search=relay%20sockets)

This would be a typical way to mount an industrial relay. The socket mounts on a DIN rail or via screws. Some of the relays have the indicator and check buttons. Look at the DPDT ones for 24 VAC.

DIN rail is like an erector set for process control stuff. You can nearly plop anything electrical on it. Power supplies, relays, circuit cards, terminals, conectors etc. and re-use them. Everything is wired with screw terminals.

Hi,

Sorry but I bought packs of 5 each resistors and even if I couldn't read the color
Code it was stamped on the packages..

Bad-Boys-Rape-Our-Young-Girls-But-Violet-gives-willingly

Do you recall that sentence??

I was an electronics Tech. while in the Army.. I have a 10 Ohm resistor in place..

Thanks

OK, sorry. 10 ohms just doesn't seem right, but I/we don't have the schematic of the bell.

FYI: Here is a DIN rail mount transformer (not in US):

Legrand | Transformers | Transformers | Din-Rail, Panel, Wall Mounting Transformers | 12 and 24 Vac Din-Rail (http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=2019157)

Hi,

Thanks for the link.. Perhaps there's a high resistance in the input circuit of the electronic Bell.

I did write to the bell makers concerning a lighted push button but no response as yet.

Thank you

You may not even need the resistor?

You can actually measure indirectly what the input impedance is of the bell by getting an "appropriate" variable resistor. Put the resistor at it's highest value and adjust so that the voltage is half of the transformer voltage. Take the pot out of circuit an measure R. That's the internal R of the chime.

Hi,

Tried the 10 ohm reisitor, diode and a 20MA LED.. That lasted about 7 house and the LED blew out. I now have a 10 ohm resistor - diode and a 70MA Led in place and testing again.

I also added a 20ma LED and a 1K resistor across my garage push button and am testing this as well.

The garage button has approx 20 VDC - no need for the diode.

Will advise

We used the Bad boys as well for the resistor color code, even knew Women Tech's who used the same saying? Funny hearing them say it. As you try different resistances, measure voltage across LED. Too high, increase resistance.

I eventually used "Black" for "Bad" because it was easy to confuse black with brown. I also learned it as "Virginia" rather than "Violet".

Hi,

My test of the completed LED w/10 - Ohms worked fine for about 8 hours then all shut down. No Led and no chime. Took an off/on of the xfrmer circuit breaker to restore. Then all back on.

Seems that the Bell electronics shuts everything down with the LED setup in place.

Here's what I think I know so far.

The system works fine with only a diode across the button, all notes are played.

The system MUST have a diode across the button to complete all 8 notes of the chime.

Putting the LED system across the button lites and works for about 7 hours.

Putting the relay in series will add 160 Ohms of reistance and I think it will stop the chimes from playing all 8 notes. I couldn't even add 10more ohms to the LED system

If I used the 24 volt relay on my 16 Volt system I don't think the 16 volts will energize
The relay. Need 85% of the required voltage

Even if I found a way to energize the relay then I must have a diode across the button to complete the chimes.

I was thiking about a separate 24 VAC Xfrmer to energize the relay and using the contacts to switch the LED and diode in place across the switch and feed the Bell Electronics.

Any ideas?

I was thiking about a seperate 24 VAC Xfrmer to energize the relay and using the contacts to switch the LED and diode in place across the switch and feed the Bell Electronics.


This is a little confusing, but it was essentially what I said.

Your new circuit consists o a transformer, the switch/led/resistor/diode) combination and a relay with a 24 VAC coil.

A set of normally open contacts interface with the doorbell to the wires leftover.

No new wires need to be pulled.

DC could be used as well. Remove the diode in the bell and put it across the relay reverse biased, to absorb coil collapse spikes.

Check All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices (http://www.allelectronics.com) for some surplus parts.

Hi,

Back to square one! As I reported I decided to sleep on things for awhile and installed the button the way the manufacture requested. Just the diode across the button.

I checked the bell chime and all worked fine overnight. Today it's off, no chime.

Had to switch the circuit breaker on/off to reset.

Now of course I don't know if it was the chime all along! I'm leaving everything as is over night and if it's out again I'll exchange it at Lowe's.

My only thought is was it really defective out of the box or did the LED - Diode - Resistor cause a problem within the chime??

Won't know till tomorrow or perhaps the next day. If I exchange it I'll test it for a full day.

I purchased a resistor substitution box today, thought that might be better then swapping resistors by hand while building a project!

Thanks again

When you say a diode across, do you mean diode or led? I know the led is a diode. With just a diode you will be shunting during the half cycle, loading transformer down.
A diode, led and resistor should work, be sure when all is in place, the LED see the required voltage.

I did some online searching because the "diode" thing was interesting. What I learned was that without the diode across the button, the chime will supposedly only ring for as long as your holding the button. It is only required on the front doorbel and not the rear.

Based on that information, I do think your only recourse is to use a second 24 VAC circuit and to put the diode across the contacts of the new relay.

Hi,

You are correct about the diode. Hold the button and all works fine. Diode needed.

My question and problem is that even with a relay I'm having difficulty putting the diode across the button when the button is released via a relay. You will always have the led diode and resistor across the button. Adding the new relay the added coil resistance will knock out the chimes if put in series.

You can use the relay to add the diode but when you de-energize the relay there goes the diode. When used the diode is circumventing the Led/Diode - I think??

Can you draw a sketch, please

I could add a separate 24AC Xfrmer and use the button to energize the 24VAC relay and control the 16VAC to the chime through the 24 VAC relay.

My supply and the bell chime are only 16 VAC.. I don't think that's enough to energize the relay.

I still like my Double connector switch.. two SPST (DPST) but I'd need to add some witing to the switch.. Going to dust off my hammer and drill for the walls, just in case.

Thanks

Hi,

Would you know if they make "Time delay" relays that energize w/o delay but de-energize with a set delay..

I know they have time delay relays but I think it energizing??

If there is then perhaps you could delay the circuit when you release the button and keep the chimes going..

Just a thought

Thanks

I think I have a way to make this a lot simpler.

Pick up a 5V relay 275-240 at radio shack and a small full wave bridge rectifier. The relay has a coil resistance of about 55 ohms.

For now get a 20 mA LED and a 50 ohm resistor, probably 1/2 watt resistor of two 100 ohm 1/4 watts in parallel.

You'll also need a doorbell diode , but let's leave this out for now.

Take the bridge and connect it to the 16 VAC transformer

Connect the doorbell switch (S1) in series with the relay and the output of the bridge rectifier. The DC voltage should be about 7V from the bridge. Don't bother using a capacitor for filtering.

Test. The relay should engage when you push the button. So far, so good.

Now add a diode across the relay coil reverse biased. Plus of diode to (-) of relay. (+) of diode to the negative supply. This is transient suppression.

Now take the 50 ohm resistor and the LED and place across the doorbell button.

Test.

Light should go out when the button is depressed.

You should be able to do this on your bench, if I remember right.

No chime or final connections at this point.

If all works out, you can upgrade the LED and reduce the 50 ohm resistor and test.

Hi,

I'll p/u the parts soon.. Here's a schematic I drew... What do you think?

I realize it has a relay, another transformer and an extra diode.

Will this do it? As you can see the extra diode runs through the NC contacts of the relay putting it across the switch when released.

Thanks

That's essentially the original design I was contemplating, but I didn't know about the diode across the button thing.

It's correct EXCEPT, the diode has to go across the (C) and (NO) contacts in the correct order.

The 5V DC design looses the transformer.

Hi,

If the diode is moved as you suggest, wouldn't that take it out of the circuit when the button is released, and the chime would stop?

Pushing the button gets it going, and after the relay de-energizes the diode on the NC connects it across the switch. The LED/Diode is only to lite the switch.

Am I missing something.. I toyed with it's placement and did start with the NO side.

Thanks

Hi,

Very strange. The bell is still working

I think it will work the way you've drawn it, but it's now how the mfr intended. They want the diode across the switch and then the switch shorts it out when pressed. Your circuit doesn't operate that way.

Part II

There is a non-destructive phenomenon with CMOS chips where charge gets moved inside the IC and alters the behavior. Eventually the charge leaks out and the device works again. I had a co-worker who slid a bike with a bike speedometer across the car rug. System broke. Took battery out. Shorted battery terminals. System fixed. I have other stories too.

Hi,

Like I said, I toyed with it's placement. I do know that when I had it across the switch with the LED, and the resistance was too high it didn't work, as if the diode wasn't there.

Actually, while writing this I was looking at the drawing and I believe you are correct.

Putting the diode on between the C and NO puts the diode into the "Front" chime as they designed.

Pushing the button energizes the relay connecting the C to the NO, shorting the diode, releasing again puts the diode back in series with the chime.

I hope!

Hope my bell still works in the AM - just tried it and it's still working.

Thanks

Hi,

Here's what might be the completed schematic w/16Volts. A little down hill drawing but I know electronics can go up hill!

I haven't tried the bell chime yet - too early here.

Thanks

Hi,

I believe I have an error in my bridge set up..

Back soon.

This is basically what I was thinking of. If I remember my formulas right you'll get about 7 VDC or so. As long as the voltage can cause the relay to pull in you should be fine, otherwise the overvoltage is only going to last for the length of the press.

Hi,

Good news first: The chime works as the mfg suggested - all OK with only the diode in place, no need to exchange.

I bench tested the bridge and got 16VDC out of the Bridge. Is this the over voltage you spoke about? Can't it be reduced to the 7VDC?

I believe I made a wiring error after looking at your sketch.. I put my resistor substitution box together today. I wanted to get something working!

My previous sketch had the bridge wired incorrectly, which I saw before I actually wired it.

I'll give your sketch a try tomorrow.

Thanks for the sketch and help

Hi,

I'll re-measure the voltage after I rewire it correctly.

Thanks

When you say diode, I take you mean Led, is it a 7 volt Led?
The resistor you add should bring the voltage down to LED Voltage.
Since you have 16 Volts DC, To find the resistor, divide the LED current into 16 minus the LED voltage.

I would try the full wave bridge at the door bell, Parallel the ac in on bridge with door bell contacts, then take the DC out, through resistor, then to LED, other lead goes to bridge Minus.
If the full wave bridge is too big to fit in the hole, make a bridge out of 4 diodes, then you can assemble so the hole needs to be big enough for 2 diodes side by side, inline with the other 2 diodes side by side.

Hi,

No, it isn't the LED it's a chime diode. The system is working as it came out of the box.

If you recall I had the normal system stop working after 7 -8 hours that's why I'm testing it as the manfg. Suggested, in case I had a bad chime.

The circuit I'm testing ( Relay - LED - Bridge ) is on the bench.

Thanks again. I'll be at it tomorrow, I think

Hi,

Thanks.. I have enough room at the Chime for most things. There's an empty outlet
Box, that could be made into a duplex box, that I ran the bell/Xfrmer wires through.

If that didn't work I can easily get to the Xfrm in the basement as well as have an easy
Way to add any wiring I need from the xfrer to to chime box.

Hi,

My doorbell sw. is like the one in KISS's pictures, recessed. Plenty of room in the switch for the LED - Resistor and diode.

I would be able to mount the extra diode - Bridge and Relay at the chime works.

I don't see why you need anything at the chime, just the parts on my last post, all done at doorbell.

Hi,

I'll try getting it working on the bench then look at it again.. You may be right but I seem too be focused on the bench.

Radio Shack has a 5.1 and a 12 V zener diode. If you get about 7V from the bridge, you can put the Zener reverse biased across the relay coil. This would regulate the voltage there, but I don't think you need it.

If 70V gets you 100, the 16 might get you 22. In which case a 24 VDC relay would work.

Based on this design guide:

http://www.hammondmfg.com/pdf/5c007.pdf

A 12-15 volt relay should work. If you'd like, put a 12 V zenier revered biased across the relay and a normal diode reversed biased across the relay.

Then your resistor should be Rtotal = (14.4-2.1)/20mA

Total R should be: (Rtotal) - (Relay Coil Resistance)

Hi,

Thanks again... I'm looking

Hi,

Follow up:

I have the complete circuit and chime on bench with the Chime and LED working.

I used a 33K 1/2 watt resistor in series with the 20MA LED.

I have 16V at the Bridge when the button is open and 15v when pushed.

I have 2.6V across the LED.

I will let this run and advise.

I'm thinking that if this works out OK, I'll mount everything on a PC board and mount this to the Single gang box that's directly behind the chime, with the parts facing into the box not outward. I can drill a hole on the top and bottom of the PC board to screw the PC board to the box and drill a larger hole for the wires to run through.

Thanks again, will let you know.

Why not mount the PC board on standoffs on the cover of the single gang box, board facing in?

You may be able to bring wires out the cover with grommets and the wires tied with an Underwriter's Knot.

PS:
Why was the sudden interest in lighted buttons?

Hi,

That's an idea.

When I bought this house 4 years ago they had a wireless chime that was hard to hear through the house. An inexpensive one at that.

He also cut the pushbutton wires off at the button. He did leave the button wire and the xfrmr wire sticking out of the wall behine the wireless chime.

I added the single gang box for the wires but kept the old chime.

I was doing some electrical work for a friend and replaced her chime, w/o a lighted button and all worked fine.

I liked the sound of her door chime and bought one for myself but I alway's liked a lighted button and here we are.

All still working on the bench, let you know.

Hi,

Get your computer hard drive fixed?

I set up a dual boot Win.XP 64 Bit with Win.XP 32 bit.

Been thinking of adding another boot, Windows 7-- 64 bit too fool with...

The bridge should be 0 when shorted with the pushbutton.

Hi,

The really resistance is in series with the bridge with the button pushed.

Thanks

Sorry - Relay

Strat:

Lay off the alcohol. The bridge is the power supply, basically because a 16 VAC relay is hard to come by. There is no way 0 Volts will activate a relay. Without a cap and probably not measuring the voltage with a true RMS meter, all sorts of odd voltages result. There is also no regulation.

A varistor on the mains or the 16V would enhance the design.

Hi,

I was trying to be kind..

Strat knows better than that.

The circuit is weird enough as it is. It's easy to make the circuit complicated and it's hard to simplify.

Hi,

Yes you're correct, the circuit is working, no need for a filter system etc.

Thanks

You are Missunderstanding, When the doorbell is pushes, there is ZERO volts across door button, that is where I woud have the Bridge.It WILL go to zero if wired like my post dated( Jul 18, 2009, 05:23 PM), maybe in your designs?
I wouldn't worry about regulating or filtering.
I wasn't thinking about a relay.


Only the Led, resistor, and full wave brige rectifier at door button, Nothing added at the chime box, no extra wires, no added relays.
What is the final drawing that works?

Here are a few interesting thread


http://www.thathomesite.com/forums/load/wiring/msg0700072921211.html?2

Here is some info from Zeneth's website. Stupid answere, essentially.

DESA Customer Care Center (http://www.desatech.com/commonquestions.cgi?products=Wired%20Doorbells)

This link, probably the one I trust the most:

http://www.nutone.com/PDF/InstallGuides/LA164ins86527.pdf

Suggests that the diode is there so that the chime receives power at all times. It looks like they are suggesting that a lighted pushbutton (assume incadesent) can be used as long as the diode is still used. Why the 40% reduction in brightness, I don't know.

Strat:

Now I see what you're trying to do. Power the light via a bridge. The problem, I think, is it depends on what the "load" of the doorbell looks like.

So, I might agree, that the diode allows the chime to have power all the time. The chime detects the change from pullsating AC to AC and activates the chime. The LED/resistor combination, just doesn't give enough power to the chime. An incadescent light just never allows the chime to see the difference between pulsating AC and AC.

Based on that inferred information a diode in series with an incadescent lamp may work because the pulaing AC to AC would be detected. The chimes internal resistance would determine the brightness of the lamp.

The drawback would be the incadescent lamp burns out.

The design does satisfy:
1. No new wires
2. long life of lamp. LED just gets dimmer over time
3. Small size: LED/Resisor/relay/bridge
4. Three additional parts can be used to increase reliability.
... a) coil back emf supression (diode)
... b) Coil voltage clamping (12 V zenier). You'd have to hold the button till your finger got tired to cause issues.
... c) ZNR clamp on mains or transformer. Not a bad idea to protect the chime and the LED.

SO, I'm going to hypoteisize that the diode allows the chime to be powered at all times and front doorbell presses are detected by looking for a change from pulsating AC to AC.

The back doorbel doesn't require it because that oncepowered, it can be detected conventionally.

The doorbell switch across an incadescent lamp and a diode will work with a reduction in brightness of the lamp. A lihted doorbel would have to be modified to work this way. Nutone claims theirs will work with a lighted doorbell with reduced brightness.

Now the conventional system with the diode across the button and a bridge across that like I think Strat is suggesting, may indeed work, but with more parts in the button. 5 single diodes, resisor and an LED. 4 of the diodes could be replaced by a bridge. The design might have merit. Eliminating relays would be a good thing. Interesting?

I HATE IT WHENMANUFACTURER'S DON'T PROVIDE EQULIVELENT CIRCUITS OF WHAT THE WORLD SEES TO THEIR DEVICES.

Hi,

If you recall, my problem began by setting the chime up just the way Zenith suggested.

The wired chime did NOT come with a push button so I bought a Lighted one.

The set up - lighted incadescent button and diode worked fine for about 7 hours then everything went dead. I had to shut off my circuit breaker to the transformer to get it working again.

So, either my eyes and ears are wrong or Zenith isn't correct.

The setup with the LED has been on the bench overnight, some 24 hours and all is working.

Too bad Zenith didn't bother answering my Email about this, perhaps it could have helped THEM.

Here's the working circuit.

I'll be picking up the P.C. board tonight and put it together.

Thanks

Here's the manual if you don't have:
http://heath-zenith.hcents.com/data/manuals/598-1113-05.pdf.
Personally If not working yet, I would try the LED, Bridge, and resistor at doorbell with the mentioned diode across the button.

Hi,

Thanks for the link... All working fine

What is the final design?

The latest FINAL design was posted at post #100.