Hey there - bummer!
let's see if we can get you up and running...
bryansbizaar wrote:
Hi there. I need some technical help to fix my Tweed Royal. Last night, I switched the amp on and didn't get any signal. The jewel light was on, but no sound. After looking around, I realized that one of my speaker wires became accidentally disconnected. Unfortunately, it seems to have fried a lug on my rotary 4pol/3pos standby switch.
The loose speaker wire is probably a red herring (but maybe not). I've heard of output transformers melting down when a speaker is not connected for a long time, but have not heard a of bias resistor melting down because of this.
bryansbizaar wrote:
I hooked the amp up with a voltage regulator and confirmed there was a short. It sparks at this point that I mentioned where the wire and the 470 ohm resistor connect to the switch. The lug appears quite loose. Along with the spark, there was a burning smell. It appears that this point became overheated and I suspect this has created the short in the signal. The fuse did not blow and there does not appear to be any other obvious visual signs of damage.
Replacing the switch appears like an obvious first step. Before I just order this part, is there anything else I can check in case I need to replace something else as well?
Need to figure out what burnt. Are there any scorch marks on anything at all? If it were me, I'd replace the 2 470r resistors and the 25uf cap too, since they are not expensive items and all connect to that point. I also would try both 6V6 tubes in another amp to see if they work. A bad 6V6 could take out the bias resistor like that.