Latest, hopefully last update. I called Carvin about a month ago and reached a real person in their tech department. Since I was still in the 1 year warranty they told me to remove the power amp from the cabinet and send it to them and they would fix it. So I did that. When I took the amp out I was surprised to see great gobs of silicone RTV deposited like some kind of random incontinent rubber bug got loose in there. You can see pics
here, post #31
I packaged up my amp along with a long letter explaining the symptoms I outlined above. I also stated that since the problem is temperature-sensitive, and RTV is a good thermal as well as electrical insulator, I was concerned about the non-workmanlike manner in which it was so liberally applied. I contacted the guy I spoke with and asked him directly what he thought of it.
Never did get an answer, but last week (about 2-1/2 weeks after I sent it to them) I received an email saying they fixed my amp and were sending it back. I replied with a thanks and also asked if they could tell me what the cause of the problem was and how I can prevent it from recurring. They answered "gee we don't know, I don't have the tech's notes, but we fixed it and you're all set." The amp arrived today, looking like they gobbed a bunch more RTV on it. More pics at
same cafe post.
So I re-installed the amp and tested it out. Works fine, sounds just as good as ever, but I won't know until next summer if it really is fixed as our 90 F days are over here. So I give Carvin a medium-high (7 out of 10) rating for customer service - they were responsive over the phone, they kept me informed on the repair status, shipped back to me no charge. But they weren't able to tell me what the problem was and as a former nuclear submarine electronics tech I hate to see such sloppy work, and I wonder about the silent treatment when I called them on it.