Hi folks, My name is Allen, and I'm new to this forum, although I have used it for many things. Lots of great info and helpful folks. I was going to post my thoughts and questions on the amp that I want to fix. I did a lot of research, however I need other peoples opinions about this as well. It can sort of get confusing, and frustrating when trying to get info on vintage amps. I bought this amp used about a year ago. It is a Fender Twin Reverb Silverface amp. This amp was gigged pretty heavily I believe. I got a great deal on it. This amp was working great for me for the longest time until recently. I turned the power onto the amp, at this point the standby switch to turn on the amplifier was turned off. As soon as I flicked the standby switch to on, then all I heard was a popping sound. So it turned out that the fuse had blown, which sort of surprised me, but this fuse could have been in there a while. So I finally tracked down and ordered online, some 3A 250V slow blow fuses to replace the fuse of the same rating that was in the amp previously. However, again it powered on fine, but when I turned the standby switch to on, there was a loud hum sound and a large glow of light out the back of the amp. The fuse itself didn’t blow, but I am pretty sure that one of the power tubes on the input is gone, because the glass on the side of it is black. I am not sure as to what caused this, but I am hoping to fix this amp back to operating condition. Something must have finally failed in it. It still has all the old caps in it, which will have to be replaced. Just trying to figure out what it was. I have tried to date the thing, and the closest that I can get is that it was made in 1967. This is based off of the transformer number and cross referencing it to the fender database. (there are three transformers I could only get a number off of two of them though EIA-606-634 and EIA-606-701) http://www.fender.com/en-CA/support/articles/amplifier-product-dating/ I know that you can use the tube chart that is posted on the inside of the amp housing, but I couldn’t find anything on what these numbers mean. However I can also find the date from the serial number that is punched into the metal chasis (A627164). This dates suggests a date of 1973. http://www.superiormusic.com/page195.htm I am still in the process of figuring out what circuit this thing used. I am finding it a bit tricky, because I am still not 100% sure that this amp is dated correctly. Even though the number on this suggests 1967, it could possibly be later. This amp might be just on the border of production dates. The circuit diagrams that I have found do not show a master volume on them, even though this silver face does come with a master volume switch. I believe that I am dealing with either the AA270 or the AA769 circuit. Have to find the differences between the two, they seem pretty similar. Since I have everything apart, I am going to blackface it switching it over to use the AB763 circuit.