The box only has 1 BNC input for the 1 probe, and 1 audio jack as the output to the soundcard/laptop,
I do have meter leads with crock clips and do have a BNC to crock clip lead
O.K. You should still be able to carry out the battery check I suggested. You can, as you suggested, measure the output at the headphone jack using your DMM.
At 1:1
I get 1.402vdc
That is with the positave probe on the base of the audio jack and the negative probe on the second connection point along, the BNC to crock clips have red and black clips, i set red to + and black to --,
I am wondering if i have the connectiong reversed to the phono jack
I think i see the issue here, with another set of headphones the computer sees the mic and lets me select it, with the lead i have cut up it does not!,
Is it possible it has something to do with the small board the MIC is attached to on the headphone lead ?
Could it be that 3 and 4 are exchanged?
When you measure the speaker between 1 and 4, 4 is the ground.
When you measure a high value between 1 and 4, 3 is the ground.
I have just tried reversing the wires, that didnt work either, possibly as i am using a laptop and not a desktop with dedicated MIC input, i dont think i am going to be able to get this to work with what i have,