Problem with volume

Bought recently at ebay Akai MPC1000. Taken, and brought home hooked up to her headphones, the sound is very, very quiet, with some crackle, it could barely be heard and nothing can not make out what's playing in the columns of the same ...
Main volume knob on the volume generally does not affect, may damaged in transit, this control? It turns very easily, while rec gain with some effort must be to twist, or so it should be?
The unit is JJ OS 3.12, which can be configured there is, but I do not know ...

Both record and volumn dials should be the same, ie easily moved so seems REEC GAIN sounds broken. You have to load sounds before it plays a sound. Have you loaded a samlpe??

Yes, i have loaded the sample, the sound is there, but very quiet and with crackle.

I already know that something is broken, but what?

ok, MPC1000 has a few outputs. Try them all as well as headphone out. You must assign the output of the sample though. So make sure sample is playing to right output you have plugged in

I'm having this exact same problem with a 1000 I just purchased. My sounds and programs work fine on my other 1000, but the new one is just making a faint crakling and the volume has no effect. Did you ever solve this problem?

It seems that it is just my headphone out and main outs. The individual outs all work fine. Anyone know what the problem is?