Author Topic: Improving transmitter volume  (Read 6750 times)

Offline GG

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Re: Improving transmitter volume
« Reply #15 on: October 07, 2011, 07:53:15 AM »

I differ slightly about rapping the transmitter on the table.  IMHO that can cause subtle damage if done with excessive force.   If you're going to do something like that, do it gently:  use a larger number of gentle taps, rather than a smaller number of stronger taps.   If you tap the transmitter on its edge, rotate it a quarter turn every few taps, so you don't just end up packing all the carbon in a different position.

Once you've got the carbon granules loosened up, you can keep them that way by occasionally shaking the receiver before or during a conversation.  If you do it while talking with someone, it will send a "sssh-ssh-sssh!" sound to the person you're speaking with. 

If a transmitter makes a squealing frying sound, it is likely that the line voltage and current are too high for it, and you need to fix that ASAP because the transmitter will fry under those conditions (the carbon granules will get burned) and the problem will become permanent.  The fix is a resistor in series and/or in parallel with the transmitter, to drop the DC current flow through the transmitter to 20 - 40 milliamps and in no case higher than 60 milliamps.  (Yes you should have a volt-ohm meter (VOM) on your desk, ideally with an analog meter, for making tests while repairing telephones.)

If you can't make the squealing/frying sound go away, the carbon in the transmitter is fried.  Keep it as a spare anyway; some day it may be possible to replace the fried carbon granules in it. 

Do Not replace fried carbon granules with gunpowder, just because they look alike.  Otherwise when you hook it up it will go Bang! and might hurt you:-)