I have an original Fender Blues Deluxe that I bought new in 1994. I've always kept it at home and never gigged it. I've probably never turned it up past 3. I've never had to have it serviced, but recently it starts dropping out and coming back in. Especially when I put any gain on it. After it warms up for about 15 mins it doesn't do it as much. Almost sounds like when a cord starts cutting in and out. I still have the original tubes. Does it probably just need a tube change, or do I need to get it serviced? If I'm going to get it serviced or change the tubes are there any suggestions for the replacement tubes? Maybe something not quite as dark. Maybe a speaker change suggestion. I like the sound, but if I'm going to get it serviced was thinking of some changes that could be made, or should I just leave it stock. This the is the original MIA version that doesn't have the biasing switch. Doesn't have a scratch on it.