atcomsystems.ca/forum Forums General General Telephone & Systems Information WEAK BELL IN OLD PHONE

matt and texas,

thanks for the pm matt, info was useful. yesterday i went to my gf's mother house, she thought she had an old phone in the shed. i was gonna use that for testing and probably transplant the bell into this one, but the phone was gone:(. i did not test the phone after moving the bias spring to the lower postion, it didnt look like it would function, so i moved in back to hooked postion. gonna move it back to low and test this time! also gonna put volt ohm meter across tip and ring. i used to repair laser high speed printers for a major computer giant, and had less trouble running diagnostics! lol but then, alot of the printers would tell u what was wrong!

Bob, using a DMM in this case can be misleading. Remember that it only takes a 'sample' and may not show the actual voltage if it doesn't sample while the sine wave is at peak. Also, most meters that the average guy has access to only read 60 Htz accurately, and the ringing frequency is/should be 20 Htz, altho as Ed pointed out, the telco's are getting lazy and cheap. It's easier to generate 30 Htz, which doesn't generally change the bell loudness much, but if the bell is marginal to begin with........ There is also the chance that the phone has a party-line bell-set and/or capacitor. Party-line bells ring at different frequencies. 20, 30, 40, 50, 0r 60 Htz is called 'Decimonic'. There is another set of frequencies I believe is 15, 30, 45, and 60 Htz, called 'Harmonic'. For the standard 20 Htz ring frequency, the series capacitor is/was 0.47uf @ 200-400 volts. It is buried in the network and probably has a WE number on it, rather than the value, so don't bother. If Matt's link shows you the schematic, you probably can figure out how to substitute a new capacitor. Just don't have your fingers in there when you test, that ringing voltage won't kill you, but when you 'jump' you could accidentally hurt yourself! Been there, done that! John C.

Lightning -

Yep, it shows a 0.1uf cap; right next to it though is spmething called a 152A condenser. (I think it's a condenser, it's labeled "COND".

PM'd ya the schematic.

condenser is the old term for capacitor.

The ringer capacitor is always terminals A and K on the network.

-Hal

I bet if it's electrolytic, it may be the problem.

...ok. so the cap in question is inside the network, even tho its showm next to the ringer in the schematic? i see a 50 ohm resister above the cap in the schematic also, and these compontents are in the network, correct? its been a long time since i read a schematic, so pls bare with me. so if i put a 300-400v 0.1uf cap across terminals a and k, will this surfice? oh, btw, the network shown in the schematic has the number 4258, the one in my phone is 4228, does this make a diff? bob

Well, it's not so much the .1uf cap I'm thinking, I'm thinking it's the one labeled condeser in the schematic. IOW, I'm guessing it's electrolytic and may have expired.

But I'm way over my head in what types of caps are in there.

Do you know anyone with "normal" phones that you can take it to for a try?

There is no difference with regard to terminals A and K between the networks, Bob. Yes, you can place your own external capacitor across terminals A and K along with the slate and slate/red ringer leads. You may also just connect them to the capacitor independently of these terminals if you want.

ev607797,

ok, where is the cap/condensor physically located in the phone? am i missing something?

bob