Hi guys,I have been working on a power supply of an Audio Measuring Set,the make is ESD and model# is AMS872-1.The problem is that upon switching on the frequency and every thing else operates normally except the level display.The level display shows a one which indicates an overload.Now I've seen a similar problem like this with another AMS and the fault was a short on the power supply,but this is not the case.The unit was working correctly before,the only thing that I've changed was a FET N channel(part no.SiVN 10k) I took that out to repair another unit.Now i'm not sure if the FET I've replaced is the correct one cause the orignal FET(part no. SiVN 10k) was not available so I've used a similar one.Anyone with Knowledge on Audio Measuring Sets can you please help me.Thanks