AC hum Fender Cyber twin

[Lastnote]

Bill,Enzo,

Thank you both.

Knowledge is power and the more insight I get on this amp the better are my chances of repairing it. Now, to do the hard work-checking solder joints and caps. I keep you all posted.

Respectfully,

Lastnote

[Enzo]

You'll see the large main filter caps inside. With the thing powered and connected to speakers, just push the caps a bit with a wooden chopstick or other insulated thing. Does pushing on them cause the hum to try and stop, even momentarily? If so, then that reinforces solder issues.

[Lastnote]

Thank you Enzo,

that is my next step.

Respectfully,

LastNote

[Lastnote]

Enzo,
Below is a audio of the noise the amp is now making. This is the first time it has the static noise on it. Taping the pots and moving them did not have an effect on the hum and noise.

https://drive.google.com/open?id=0By...m1fNzc0ZGthUm8

Respectfully,

[Enzo]

Still sounds like a loss of filtration to me.

[The Dude]

......Taping the pots and moving them did not have an effect on the hum and noise......

He asked you to tap the caps not the pots. I'm with Enzo here- sounds like a filtering problem. The main caps are soldered into the board from below. What Enzo is getting at is that the solder has likely cracked loose. You can either inspect the joints, or push/pull the caps to see if they might temporarily connect. If you lightly tug on the caps, you might be able to feel that one is loose.

[Lastnote]

I did not try to move the pot, I meant filter caps (cap's was the subject matter/thread of the discussion). I moved the 2 large brown filter caps and the smaller ones, no effect. Anyone know of any pitfalls i should be aware of when taking this amp apart?

LastNote

[Enzo]

Pay attention and take notes. If you have to remove wires, draw a map, tag the wires with tape notes, take photos, do what you have to do to make sure all the wires go back where they belong. I don;t recall, but you may have to demount some smaller assemblies, like maybe a rear jack panel or something to clear room for the big board. I RARELY have to take a board out, usually I free it and flip it over while still wired, or mostly wired. SO I get at the underside. I can't think of a time I pulled a board and took it elsewhere from the amp chassis. The amp relies on the chassis for a heat sink, but if I recall, ther is a large aluminum bar involved. If so, mark it in some way so you know which way to return it. It needs to sit flush against the chassis and the board. I put a little arrow with "rear" on the end of the rods, using a marker.

I seem to recall a stiffening rod was added to the chassis after production.

I find a lot of times screws have to come out in sequence. I have a lot of the plastic tubs that soft cream cheese comes in - little white things that I think are 8 ounce containers. They stack neatly. So if I take off a bunch of screws for a top layer of something, they go into a tube, then I set another tub in the first, and the next level of hardware goes in that tube, and so on. Now I have then stacked in order, and reassembly works down teh stack in reverse order. Some amps use all the same size screws, but others don't, and I don;t want to try and remember machine screw or sheet metal for each spot.

So like the panel: Pull the knobs, set them aside. Are any different? Is one or two made to fit some odd shaft? Separate any like that. Now all the pot nuts come off and jack nuts, and that is the front panel, unless ther are a couple small screws too. Any rear jacks and controls get a separate tub. Etc.

If I plan to set the project aside, like to go to dinner, or to bed, or to order parts, then I dump each tub into a pill bottle or film can or zip baggie or whatever. And I sit them inside the amp.

That is all generic advice.

[Lastnote]

Thank you Enzo,

I will take that good advise to heart. I will let you know as I go along.

Respectfully,

LastNote