Can anyone identify the terminals on a Friedland 454 chime?

[haggis999]

I inherited the door chime shown in the attached photo from the previous owner of our house. It could be well over 30 years old, but still works perfectly and has the advantage of being louder than a modern electronic chime. It is marked Friedland No. 454 inside the outer cover (it's different from the more recent D454 Warbler).

The recent installation of a new illuminated bell push caused me to investigate the internal connections of these chimes, but I was forced to proceed by trial and error, as the purpose of the terminals marked 0, 1, 2, 3 and 4 is unclear. I've got it working, but as a matter of academic interest I would still like to have a better understanding of the all the wiring options for the Friedland 454.

Can anyone shed some light on the intended purpose of each of the five connections?

 

[winston1]

Two terminals for the solenoid, two terminals for the mercury switch, and one loop terminal for the transformer and bell push.

That's a guess.

 

[haggis999]

I've only just realised that terminals 3 and 4 must be for the two ends of the solenoid. You can see the bare copper wires going from each of these terminals into the body of the solenoid housing. It's slightly difficult to see in the photo, but the mercury switch is connected between terminals 1 and 2. The two wires from the transformer are currently connected to terminals 0 and 3, while the pair of wires from the bell push are connected across terminals 0 and 1 (ignore the single white wire also connected to terminal 1). There is also a jumper wire that goes from terminal 2 to terminal 4.

In the current connection scenario, one end of the solenoid is fed directly from the transformer, while the feed to the other end goes as follows.

Transformer - T0 - bell push - T1 - mercury switch - T2 - jumper wire - T4 (solenoid)
​

As soon as the button is pressed, the solenoid moves to the right and strikes the RH chime. As it does so, the mercury switch opens and cuts power to the solenoid, which retracts and hits the LH chime. Once again the mercury switch makes contact and the cycle then repeats.

So far, so good, but there are more terminals than necessary for such an operation. I'm guessing that they probably allow for the addition of a second bell push (at the back door, say).

 

[bernardgreen]

Beaten by a Haggis

The front door can be repeated ding-dong and the back door single ding-dong

 

[Taylortwocities]

There's a detailed discussion about this very chime at
http://diy.stackexchange.com/questions/80293/purpose-of-mercury-switch-in-old-doorbell

 

[haggis999]

Beaten by a Haggis

The front door can be repeated ding-dong and the back door single ding-dong

Many thanks for your useful drawing, which covered the optional battery connections I had not yet considered. Clarity has now emerged. A quick test has also now proved that I could connect a back door bell push across terminals 0 and 2 (getting a single ding on press and a dong on release).

 

[Taylortwocities]

Couldn't resist

 

[haggis999]

There's a detailed discussion about this very chime at
http://diy.stackexchange.com/questions/80293/purpose-of-mercury-switch-in-old-doorbell

I had actually stumbled across that link a while ago, but was not convinced that its guidance was reliable. Now that I have a proper understanding of exactly how these chimes work, it confirmed my feeling that the recommended wiring in the only detailed reply was incorrect. Under battery operation, this wiring would use only one battery for the front door and both batteries for the back door. The recommendation for use with a transformer is even worse, as pressing either the front or back door button would simply short circuit the transformer!

Thanks for reminding me about that link. I will see if it is still possible for me to post a correction in that forum.

 

[haggis999]

Ah, yes. The wonderful Leslie Phillips. These days, Miss Allcock would sue him for harassment...