GK MB500

[mojobass]

Anyone had any issues with the GK MB500 head?? Last gig I noticed mine was dropping volume a few times!? 

[msb]

The fan in my MB200 somehow got gunked up and stopped working. Then came the pink ring of doom. I do know a qualified repair guy and the fan was fixed , but other damage was done , the power module had to be replaced , and some little things got burned up. 
Today the amp works perfectly.
 

And I’m reassured when I hear a fan kick in. 

[King Tut]

I had to have my XLR socket replaced under warranty, other than that it's been faultless and well travelled. Try cleaning the FX send / return sockets and/or putting a patch cable between them.

[rOB]

No issues with mine. Had it for years.

[cetera]

Put a short patch lead between the send/return inputs on the fx loop. Sometimes an oxidisation build up has this effect (pun) on a GK amp.