6G2 Brown face Princeton issue

[dogburn]

I'm going to re-think the grounding once I get a 100 watt heavy duty soldering iron so that I can solder directly to the chassis. I'm going to make sure the cap can is grounded better for one thing.

You don't have to do much to test whether the B+ wire is interfering with the copper bus bar - just push that yellow B+ wire from the cap can away from the copper wire.

[gtrmac]

I was not happy with the grounding so I re-worked that part of the wiring. I bought a 100 watt Weller iron and soldered ground nodes directly to the chassis. It was necessary to rough up the locations with some sandpaper but now the ground points are solid. I was also able to solder the tabs of the cap can to the chassis this way.

The Tremolo Foot Switch still doesn't work properly. When the wire going to to switch is connected to chassis ground there is a buzzing in the output.

I think I'll go have dinner and drink a couple beers.

[sluckey]

I feel your pain. I have one last suggestion. Temporarily ground the speed pot lug that has a yellow wire attached. Does that kill the tremolo without any buzz? If so, then connect your F/S jack to the speed pot.

My next level is to replace that black board with one of Hoffman's green fiberglass boards. Not necessarily saying the black board is the issue, but the process of replacing it will likely fix whatever is causing the issue.

[pdf64]

I suggest to try a grid stopper at V2 pin2, in the range 10k to 100k, properly mounted at the socket lug.

[tubeswell]

I bought a 100 watt Weller iron and soldered ground nodes directly to the chassis.

Works even better if you use solder flux paste.


And a powerful flat tip iron. Fender's factory ladies had big old clunky flat tip irons that were on all day


And you really need to get the chassis to immense heat for this to work - if you don't have lots of heat and solder flux, you won't get good connections - and in doing this you risk melting film caps etc.


A better method is to use a common ground buss wire that is attached to the chassis at the input jack. Much easier to solder ground return wires to this.

[Sonny ReVerb]

Look for a vintage American Beauty soldering iron. You can usually find one for $40-50. I bought one that's 200W, if I recall. I only use 'Big Bertha' for soldering to the chassis in vintage amps. The chassis acts like a heat sink. That big hunk of iron stores thermal energy so the chassis can't wick all the heat away. I use a copper ground buss wire in new amps.

[Helmholtz]

A steel chassis is not a very good conductor (so adds resistance) and it's ferromagnetic (so adds inductance).
It should not be used for any signal or power supply currents.
Multiple chassis grounds invite ground hum and can cause unwanted coupling effects.
Single chassis ground and a copper ground bus is a way better solution.
I like a 1.5mm dia silver plated copper wire.

[sluckey]

Did you try the suggestion in reply #52 for the trem f/s issue?