AKG 240s — busted cable or phones?

[Lotus 7]

The easiest way is to get an ohmmeter to check the continuity of the removable cable.

There are at least (6) versions of the K-240 with the latest being the K-240 Studio and Studio-II.

Set the ohmmeter to a low resistance range (usually marked X1) and check for a low reading (1 ohm or less for these connections)

3-pin headphone connector ----> 1/4 inch TRS plug
Pin 1 ----------------------------> Shield
Pin 2 ----------------------------> Ring (R)
Pin 3 ----------------------------> Tip (L)

Then check for any shorts between the three parts of the TRS plug. With the headphone-end disconnected from the phones, you should have an open circuit between all parts of the TRS plug. (No connections between the shield to tip, shield to ring and ring to tip)

If the (3) connections are good, and there are no shorts, the cable is OK and you will have to check the phones themselves for proper internal connections and for voice coil resistance.

To check the individual phone voice coils, again set the ohmmeter to its low range. Connect one ohmmeter probe to pin 1 on the headphone connector, and then touch the other probe to pin 2. The ohmmeter should read between 25 and 55 ohms, and you should hear a "click" from the right phone. This will confirm the proper operation of the right phone and the crossover wires in the headband.

Keep the first probe on pin 1 and touch the other probe to pin 3. The ohmmeter should again read between 25 and 55 ohms. You should hear a "click" from the left phone. This confirms the proper operation of the left phone.

A schematic of the K-240 Studio, Studio-II is attached below.

Hope this helps.

[mahler007]

Thanks so much, Lotus 7!

Cheers,
Andrew