Thanks yutech and Enzo,

I put a cable to the send and return loop and the problem goes away. And I finally get around to open the amp and cleans all the jacks tonight. The amp is working fine now.

I find if I leave the cable on the send and return loop (a 19 feet cable I have spare), it sounds a litter cleaner which I like, so I leave the cable there at the mean time. Is this possible?

Thanks a lot for the replies. I almost went out to get a Tech 21 TM60 out of frustraction, but the Laney is working fine now, and I like it because I can plug an acoustic or a electric to it. It is really geart for a 10 year old amp.

I am looking for help on troubleshotting my Laney GC 60A solid state amp. If I plug my guitar to the front panel (with the amp buildin tone and volume controls etc..), the sound will cutoff sometime. If I turn the amp off and on again, it will get back to normal.

This never happens if I use the return loop with padels. The amp will not cut-off this case.

What is the potential causes of this and how can I fix it? Thanks.