I have a broken input lead (microjack end, can I

On the Sony MDR-NC20 model the head phone lead is fixed and cannot be replaced. If the lead is broken it is a lot easier to just replace the entire headphones.

There is a broken wire in the lead. You can replace the cord or locate the broken wire/s break the lead at this point and rejoin the wires. Make sure the joins do not short against each other. This joint may look a bit untidy.

Without a schematic you can still trace the circuit to locate the fault.

Put a music source or sound source into the bad channel and a good channel, and with an oscilloscope or with a pair of high impedance headphones with test leads on the ends- you can set up a low z headphone with an impedance match trasformer, make sure you have test prod ends on one of the leads. The other can go to a chassis ground. Start at the input and work your way forward comparing the signal between the good channel and the faulty channel. When you lose the signal or you encounter severe distortion, you are in the vicinity of the defective part.

Common failures are a Deffective 4558 or TL072/TL071/TL074 IC chip. You may have a faulty electrolytic capacitor, or even a faulty bypass caoacitor in general. Bad solder connections, even a broken fim resistor.

With the IC chips, the usual power pins for an 8 pin plastic or ceamic DIP are pins 4 and 8. usual outputs for the 8 pin are 1 and 7 the remaining pins are the inverting and noninverting inputs. 2 and 3 and 5 and 6.

Also check switches and especially those with interupts on the input and output jacks- they can get dirty.

Take it into an electronics store, a technician will be able to connect another 3.5mm jack to the headphones.

Take care!
damnor01

there will be 2 wires in different colors inside the cable,

these wires are enamel coated and sennheiser has best quality coating over the wires, so soldering this could be a bit messy - this is the procedure to do so

first take out these wire leads out for about a centimeter from both the ends, try to loosen the leads and yo will find small clustered strands of fiber wound between the leads try to remove those fibers (only the visible ones) completely from both the ends of the exposed leads.
take a blade and try to wipe out the enamel coatings from the wires (make sure that the 2 leads does not touch each other after removing the enamel) now connect (solder) both the ends of the wire with their respective leads (eg. red with red or green with green as applicable) now you should be good to go

Please understand this is a delicate job and require atmost attention use cello tapes wherever applicable and tie knots at correct places to avoid further damages

See my tip on replacing dodgy/cables plugs on headphones

All you need to do is solder a new plug on to the end of the remains of the cable coming out of the headphones, then buy an extension lead. It will be much easier than replacing the entire lead, as getting into headphones is a very tricky thing to do.

You need a 3.5mm mini jack coupler lead with phono plugs on end plug one end into your headphone output on ipod and phonos into your amp lead must be stereo

All you need is a 3.5mm mini jack to 3.5mm mini jack stereo lead, plug one end into the "portable in" input on the denon receiver and the other into the headphone input on your ipod. Et viola.

Hi evtan

The only thing I can suggest you do is to swap the right and left inputs to the transmitter base over whilst wearing the headphones. If the fault transfers to the other channel, then you have a faulty interconnect lead that needs to be replaced. If it stays with the same channel, then the headphones or the base staion will be faulty. Best bet then is to return it to the place you purchased it from and request a replacement unit,. Thanks for using FixYa....a FixYa rating is a great reward from you to me for helping out :) Cheers

regards
robotek