Trouble with my 25hz harmonic ringer in my North Electric 7H8 wall phone

[davidbholcomb]

I have a North Electric 7H8 wall phone. It works great both on my house line and with my Panasonic Easa-Phone. One small problem, it does not ring. It wants to, the harmonic ringer moves but the best I can get out of it is a really small ring by placing the bells really close. I have spent most of today reading just about everything that I can find on this site about it as well as discovering Paul-F.com's site where I discovered that my ringer is a H-224-E, 25hz, standard impedance ringer. Basically I have come to the conclusion that I have to change out the ringer for it to work or live with it, since the harmonic ringers need a frequency that is not provided for by POTS or my Panasonic Easa-Phone. My question is this, is there something that can be made to send 25hz down my phones line(if it is isolated and off line from everything else) to make it ring and hear the old sound of the bells?

[Phonesrfun]

Other than some dramatic trial and error modifications to the harmonic reed, which is the stiff flat metal piece that holds the clapper arm to the armature, there is little that can be done.  Normal POTS ringing current is 20 Hz, but the harmonic ringers are designed to be VERY selective, sometimes to within a cycle or two.

Some on this forum have had reasonable success at modifications, and you can do a search and find those threads.

For me, I normally have a great deal of patience in some selected areas, but I just don't have the patience to mess with harmonic ringers. 

Good luck

[Phonesrfun]

PS

The only other way I know of to get 25 Hz in these days is to get an ATA for Voip that has a programmable ringing current.  They do make such ATAs but don't remeber which makes have that feature.  If you do get such an ATA, you can join C*Net and talk to other collectors all over the world.

[twocvbloke]

The only other way I know of to get 25 Hz in these days is to get an ATA for Voip that has a programmable ringing current.

Or maybe send it to a country where 25hz is the default ringer frequency...

[dsk]

......
Or maybe send it to a country where 25hz is the default ringer frequency...

Yes! We use 25 Hz ringing here in Norway   (and I don't have any North telephones)

On the other hand, the 25Hz ringer is tuned to definitely not ring at 20Hz. I'm far away from an expert, but since 25hz makes the clapper move faster than at 20Hz.  So moving the clapper/hammer out as far as practical possible, or in other ways increase the load would be a good idea. (Lead weight for use on a fishing line??)  The spring is probably fixed in a way making modifications hard.This page tells something about this: http://www.paul-f.com/NorthRingers.html

The picture under is "stolen" from this page. The red arrows points at the little air gap to the moving part. The smaller this is, the stronger the force from the ringer motor.

dsk