"The phone is a remarkably complex, simple device, and very rarely ever needs repairs, once you fix them." - Dan/Panther
Started by Fennec, March 31, 2018, 08:43:42 PM
Quote from: andy1702 on April 02, 2018, 07:46:45 AMThere shouldn't be any requirement to put any additional capacitors inside a UK phone or bell box. The rectifier 205 is the correct modification and was commonly used on later 700 series phones. The 3.3k resistor is part of the conversion for UK plug and socket use. Anyone outside the UK using a traditional 2 wire system probably shouldn't need that either.
Quote from: dsk on April 02, 2018, 08:35:57 AMI mainly agree, the extra resistor/capacitor will only be there to limit the pretty high ringer load, often wanted when the phone is used together with others on the same line, or when the ATA gets problems with such loads. Different 1 kilo-ohms ringers has different impedance, and I have one telephone with a 1 kil-ohm ringer and 2 uF capacitor drawing so high ring current that my old sxs believes it goes off hook, but with another phone with the same values it works great.The UK conversions with use of a resistor is by my opinion a cheap and not so good solution, but it has been a tradition in the UK. A resistor limits the load and has a considerable loss ending up in heating the resistor, but a capacitor adjusted to let the ringer circuit have the same impedance will have almost no loss of energy. Of course this is much more complicated to adjust, and you may not have any standard values to put in.dsk