Hey guys, this is driving me nuts.

I have a client that has 1 Doorbell button, 2 (10 song) chimes.

Model of Doorbell kit is the Heath Zenith Harmony - HE-2319-OF
He just ordered an additional Chime of the same model family.

The Transformer I provided is the MGT598 16V/30Va

I also installed a diode at the button so the entire song would play, otherwise, it only plays a second or two.

One Chime (main floor) works perfectly! Once the other chime (basement) is added, the main floor chime still works perfect, but the basement chime only plays the first note or two.

I have the Chimes paralleled per manufacturers instructions. Do I need a different value diode at the button? Or perhaps the transformer needs to be larger? Any help is appreciated.

Odd indeed.

A diode allows current to flow in one direction only; if it's doing that for one doorbell and you add a second doorbell, the diode should function for both or malfunction for both. These things also draw very little current so a larger transformer does not seem to be indicated.

Try reversing the plus and minus at the second doorbell. This is just a stab in the dark but worth trying.

Try drawing up a schematic so we can see how the thing is connected, or give us a URL to a manual on line, showing us which connection scheme you're using.

I think you are in totally unique territory here. Take a look at the manual...

[Link: heath-zenith.com]

Note there is no info on how to make two chimes work. I'm guessing that by installing two chimes in parallel, that you've created some sneak current path, or have damaged one chime or the other.

I think you are in uncharted territory, and without knowing how the circuitry in the doorbell works, you can't make the assumption that paralleling them will work.

Note there is also on page 7 both a website and phone number for tech assistance. I think that is your best bet.

These devices are electronic, not just a buzzer that sounds when current flows. So just paralleling them may not work.

Link is weird. Doesn't open the pdf, but instead opens a Save To window!

Everything he says is true.

However, upon further reflection:
You could use the doorbell transformer and the doorbell buttons to close a two-pole relay. Each pole of the relay would be wired like a push-button per the instructions, complete with its own diode across its terminals. This way the two chime units would not be wired together as each would be switched on separately. They can have a common power supply; it's the common button that doesn't work.

Now the challenge is to find a relay that works at 16VDC. It might be easy but that's an unusual AC voltage for anything but doorbells. If the relay coil requires a small enough current that the transformer can close it as well as run both chimes, you're in business.  Perhaps a 12VDC relay might work, or it might chatter like a buzzer.  If you can't find a 16VAC relay you'll have to try this.

If you can't find a relay that doesn't chatter, you could convert the 16VAC to DC; regulate it to 12VDC, and have a good supply for a 12V relay.  I'm now going off the deep end: once you have DC, you could have the doorbell buttons turn on a transistor to trip that relay.  You could even have the buttons start a 555 timer that would close the relay for a short period of time, starting the cycle for both chimes.  This now brings us to the ultimate---

First, a question about how these work: If you don't use the diode on the chime unit, and you hold down the button, does the chime play as long as you hold down the button?  If so,  make a system that emulates holding down the button for X amount of time.  Simply wire the two chimes in parallel, using a relay to close the buttons, not using the diodes, powering the chimes with AC per the instructions; also convert the 16VAC to 12VDC and have the buttons initiate a 555 set up as a one-shot to keep the relay closed long enough for a complete tune to play.

Are these chimes near enough to one another that you hear them both at any locations?  If so, they'll drive the client nuts because sooner or later they won't play the same thing or be totally in sync.  Now, if you can wire the chimes to multiple locations, you have wires between the units that could instead parallel off of one chime's speaker; get a small Radio Shack amp powered by DC derived from the 16VAC, and use the existing wire to put an additional speaker in the second location where you're trying to get a chime to work.

For an amp, you could use this.  It's made to work off a nine volt battery and you could easily make that regulated voltage be 9 volts with the proper voltage regulator IC:



Or even this, if you hate the client (it could happen!):



Edit: just to cover my bases here, I have tried to provide the simplest solutions I can come up with; the most elegant; and at least one using active electronics. Something of this should work for you.

I apologize for using the word "simply," as I believe once people use that word, a lot of details are usually left out. So I left them out.

I've done this same thing on several jobs by wiring from chime #1 to chime #2 (using the same model chimes) and connecting the Trans & Front the same on both.

Things to check:
1. If chime #1 works fine, take chime #2 to chime #1's location, connect it and test that it also works and is not a failed unit.
2. If it works fine, check to make sure you have the right melody selected (10 tone, not 2, etc).
3. Check the power specs on the chimes that 16vac and 30va is sufficient to power both chimes.
4. Make sure your trans and front wires are wired to the correct terminals on both chimes.
5. If both chimes work, everything is set right and you still get a 2-tone on chime #2, try switching the chimes

Good luck.