I have been using the H4N for a few years without incident. On a recent shoot the left external mic input seemed to stop working. I swapped the left and right mics between the two input sockets to determine that it was the Zoom unit at fault rather than one of the mics. I had to make do with the internal mics and the right channel for that shoot, which is causing some headaches in post.... BUT testing the unit at my desk now I find that the left channel does work but not as well as the right. If I hold the two lavaliers together and speak or blow into them the right one will pick up much more than the left (and again I can swap the inputs and it will still be the left one that has the problem, so it is definitely not a mic issue). Can anyone shed any light on what might be going on here?
Input levels on the H4n's external ports can be set independently. Make sure that when testing, both external inputs are set to the same gain level by pressing the Input button (1 or 2) on the left hand side while adjusting the Record level up or down.
If all gain settings are the same, you're not set to Mono Record mode,your input source is the same, and you're still having the problem, then there is most likely something wrong internally.
The XLR inputs are a seperate PCB assembly from the H4n's motherboard, and often times replacing that part will fix problems like you are describing.
Many thanks for the speedy response Michael! I was worried that that was the issue. I checked with zoom and they only replace product (which makes sense, and is pretty good value @ $145)so I am probably going to go for a Tascam DR60 (=$200)and keep the Zoom for use as a back up.