Crackling and other noises...

[Tony V]

I know this may be an easy answer to some of you but i wanted to ask anyway. What are the main causes of cracking and whiz pop sounds on old rotary phones. I have several and all but one make one noise or another when i use them. All my phones are loud enough on my end and sound good or better than modern phones to the person on the other end. The noises can be heard always on my end and sometimes on the other end although barely noticable. The line is clear as a bell if i use a modern phone on the line. All of mine appear to have their original handset cords and the line cords are hit and miss. This is the only reason i dont use mine daily although i eventually want to. They are only used as emergency phones for now.
-Tony

[Dan/Panther]

My best guess is, dirt, and lose connections.
Clean it up, and tighten all of the screws.

If I talk for any length, on either of my vintage phones, I've been told that the volume decreases significantly.
I have a friend that says, and I tend to maybe agree a little, that the capacitors in our phones, will break down eventually, and lowered volume, and buzzing CAN be the results.
Very typical for capacitors in audio equipment.

Boy oh Boy I said it now...

D/P

[bingster]

I've often wondered about the cap in a telephone.  We know how problematic they are in radios, and after all, the one in a telephone is nothing more than a multi-section cap can, right?

In addition to cleaning and tightening connections, you might also want to clean the contacts in the switchhook switches, and make sure they're aligned properly.  Also polishing the contacts and element backs in the handset couldn't hurt.  Beyond that, you may also want to check that the handset cords are still in good repair.  You can test the continuity of each conductor with any meter and watch for fluctuations in the readout as you move the cord around.  I've never tested continuity with a meter, but I'm sure one of the radio guys can explain how it's done. 

[BDM]

While never saying never, it's extremely unusual to have a bad cap. This has occurred in older subsets dating back 100 years. But later sets using the 101 network are FAR better sealed, and very low current/voltage. Again, not impossible, but 99% unlikely.

Clean all switched contacts. Including those accessible on the dial. In my experience, switch hook contacts have been the biggest cause by far. I use a soft file pad to clean them.

[Dennis Markham]

I was going to suggest cleaning dial contacts.  I have had low audio that was corrected by cleaning dial contact points.  It seems odd that several phones would have a similar problem which causes me to be suspicious of the telephone line.  Although Tony says that his line is clear while using the modern phones.  In my experiences crackling noises, when not a defective line (I did have a problem with my phone line from the house to the pole that caused static) was a result of old, dry-rotted wires within the handset cord.  Again, it seems odd that multiple phones would go bad at the same time.  The wires I have had that went bad were all mid to late 1950's cords in model 500's and 302's.

I use a Dremmel tool with a small wire wheel to clean all spade tips.  I also remove screws where spade tips attach and wire wheel the the flat side of the screw to ensure good electrical contact.  Usually it is a preventative measure and not a result of a current problem.

[benhutcherson]

From my limited dabbling in Radios, I believe that the capacitors which usually go bad are the electrolytics and paper capacitors.

Bear in mind that there are bunches of different types of capacitors(as I'm sure you radio guys know). I'm not sure what type is typically used in telephones, but I agree that I've never seen one which went bad. I use to go to the trouble of going through and individually checking the ones which were readily accessed, such as in the AE40, but never found one that was anything but its marked value, and so quit bothering.

I've never opened up one of the 425 network blocks as used in 500 sets, but at least the open PC board networks used in ITT and I think some later WE phones had ceramic capacitors. Those almost never go bad.

I agree on cleaning any contact, as well as checking the handset cord.

[Dan/Panther]

I agree that several factors are at work here, and no one will fix all, in radios, we have a problem with rubber coated wire, not unlike that which I found in the handset cord of my WE500, I kept peeling back the covering and was never comfortable with the looks of the insulation, though more flexible, it still felt a little dry so I replaced the cord with a never equivalent. The wire in side the handset cord could be breaking down and shorting.
As far as the capacitors, I think like BDM, he used the words "sealed better" when referring to some caps, I think that's the key, if caps are sealed very well, they will tend  to last longer.
I think that is why epoxy coated caps, at least in my experience are very seldom bad.
Paper tube, and open end electrolytics dry out much quicker.
Phone capacitors seem to be encapsulated and of very high quality.

JMHO
D/P

[Bill Cahill]

Well, I don't agree. It's not only moisture that makes caps go bad. Caps  are oil impregnated paper. The paper is generally "Acid" paper, and, it's often a chemical breakdown.

Further, I have a well made child's phonograph from about 1962 that had alot of paper capacitors, and, a bunch of ceramic disc capacitors.
Three of the ceramic disc capacitors were actually shorted.
This is a three tube  high fidelity manual portable record player.
I doubt that just because they are sealed, it guarantees the phone caps will be any better.

Some years ago, I had an old dial phone that wouldn't ring. I was told to replace the bell capacitor. I checked it first, and, it was bad. I replaced it, and, the bell came back to life.
Yes, do all the above, but, I still suspect capacitors, as well.
Bill Cahill

[Dennis Markham]

We don't know what kind of phone(s) Tony is talking about.  Maybe we are assuming he talking about model 500 type phones.  I don't know anything about collecting or refurbishing old radios but I have probably refurbished a couple hundred model 500 phones.  Any that have had "cracking" sounds were a result of bad cords or dirty contacts,  with one exception.  I have had one 425B network that no matter what cords, dials, ringers I put on it still provided static.  Since I am not electrically inclined I don't know what the problem inside the network block is--maybe there is a capacitor in there, I don't know.  But with hours of discussions I have had with other phone collectors I don't remember anyone talking about capacitor issues in this vintage of telephone, which tells me it isn't a common problem.  To have one "bad" network out of hundreds makes the likelihood of Tony having that problem with "all but one" of "several" seem rare.

I think there is too much missing information to accurately diagnosis Tony's issue.  I think though there have been a some ideas here for him to research.

[TIPandRING]

Well, what I've run across and done;

Crackling:  Bad transmitter capsule (very common in Ericofons), but have run across this in WE and AE phones. If they look nasty and dirty, just replace 'em anyway.

Dirty contacts. Clean the hookswitch contacts AND the dial shunt/pulse contacts. Here's what you do;  Assuming you're at least 21 years of age, go down to the local liquor store. Purchase some EverClear (pure grain alcohol, very strong, and not so cheap!). Soak the end of rolodex card, or other stiff note card with the stuff. Slide it back and forth between all closed contacts. Operate the contacts and repeat. Do this with power disconnected as this is flammable! Also tighten ALL screw connections and wiggle spade connections.

Inspect cords: Dry rot, broken conductors etc. will cause strange crackling.

Humming, whining, other weird noises

Try replacing the receiver element.

Replace the caps in the network (if the network is open and on a circuit board). Did this to my AE 90 (which was made circa 1972).

Just some thoughts.

[BDM]

Well Bill, the facts are, failure of these caps, even in 80 year old subsets is very very uncommon! Especially for W.E. equipment. I wont speak for the independents, but after 25 years of collecting mostly W.E. equipment. Talking with many of the prominent figures in phone collecting. Has lead me to believe failure rates are probably under 1%. Certainly not the first thing I'd be looking at in W.E. equipment.

The quality standard W.E. produced their components under was second to none. That's no exaggeration. Also, these caps operate under very low current, and low voltage. Plus no heat. The cheaper produced caps in radios and the like, suffer a far harsher life. Does this mean they don't fail? Certainly not. But I won't lead people to believe these need attention at any rate approaching those used in our old radios/TVs, etc.

[benhutcherson]

I don't have Dennis's vast level of experience, but in 30+ telephones, I have also never encountered a bad capacitor. The ones I've checked using a multimeter which can measure capacitance have all been well within spec.

I agree, check the handset cord and receiver element if necessary. With that said, however, I've never even needed to replace or even reterminate a handset cord on a 500 or 302, although I have a few that could potentially need it in the future.

[mienaichizu]

usually i also have this crackling noise on my old phones, the usual reason is the handset cord or dirty terminals. I also have this experience, when 1 phone has a crackling noise, it really affects the other phones

[Dan/Panther]

I don't have Dennis's vast level of experience, but in 30+ telephones, I have also never encountered a bad capacitor. The ones I've checked using a multimeter which can measure capacitance have all been well within spec.

I agree, check the handset cord and receiver element if necessary. With that said, however, I've never even needed to replace or even reterminate a handset cord on a 500 or 302, although I have a few that could potentially need it in the future.

I'm surprised at this, being they appear to be rubber coated wires.
When I pulled mine apart for the first time, the rubber coated wire just crumbled btween my fingers. The exact same problem in radios, but the rubber wire in radios has more of a tendency to break off in larger pieces, whereas my 500 just turned to dust, and was the same about 6" up the cord, so I replaced it.
It may not be everyone opinion, but it seems tyo me that deteriortation in Caps, Cords, and the like is in direct proportion to the sames exposure to the elements. The Telephone caps seem to be very well encapsulated, and Im my opinion is why they last, great quality. My AE, has light purple colored capacitors like you would see in high  quality pro, or miltary equipment, or early mainframes etc. Not paper tubes filled with beeswax.

D/P

[bingster]

I've seen far more perfect rubber conductors in my handful of telephones than in all my radios combined.  I don't know if it's lack of heat that keeps them in good condition, or what, but they are very commonly found in perfectly soft, flexible condition.  I do have a few cords that have crumbled, of course, but the majority are fine.