Today we have what I consider to be one of the best values on the marketplace today: a good ol' Fender '65 Deluxe Reverb reissue. Classic design, perfect club amp for those who like the black panel Fender sound. 22 watts of power through a pair of 6V6 tubes. There was a time when if I had a dozen original ones in my store they would be gone in a month. Everyone seemed to want one about 15 years ago. Now the watts war is in reverse and that honor goes to the Princeton Reverb. Those sell effortlessly enough that Fender made a re-issue of those as well. I prefer the Deluxe myself.
So hopefully my headline got your attention. These are great amps but there are a few things about modern construction that just bum me out. This one was dead, no big deal, just had a burnt 6V6 tube. The fuse didn't pop so the 470 ohm 1 watt screen grid resistor burned up. Again, no big deal.
In the old amps Fender put the 470 ohm screen resistors on the tube sockets along with the 1.5k grid stop resistors. To cut cost they put these on the circuit board. When one burns up, and it is a dramatic burn, it makes a mess. Here is the socket:
And here are the burnt resistors on the board:
So first step is to cut those resistors out and clean up the board with sandpaper and compressed air. Get as much of that carbon out as you can.
Next I bypass where the old resistors were. I also bypass R60 & R61, the grid stops. I will be moving those to the sockets as well. Why? They should be on the sockets. They don't always work when they aren't. Why risk that? I've seen it happen before, having them on the board doesn't prevent oscillation at high volumes. Simple fix.
Now admittedly, I'm cutting a corner here too. The proper way to do this is to remove the board and remove the resistors, then replace them with a solid piece of wire. Do as I say, not as I do. This does add time to the job but we are on a budget and this works just fine.
Here are the re-wired sockets:
Notice I moved the orange from pin 4 to 6 and put the 470 ohm, now 2 watt resistor between 4 and 6. I also moved the green wire from 5 to 1 and put nice sounding carbon composition 1.5k 1/2 watt resistors between 1 and 5. This is how they did it in the glory days of amp building.
Now if a tube blows again, there is less mess to clean. I feel better about the whole thing. Not to mention, if we were to put those screen resistors back there they were, the next time they burn, they will burn a whole through the board most likely, then we'll have a real mess! Prevention is easy on these amps. Do this and save yourself trouble down the road!