British royalty help

[Toastman]

Hello, everyone, I finished the British royalty overdrive today. Bought from musikding with all the parts needed.
Unfortunately it doesn't work...
Led is working and bypass too.

Anyone could spot what could be wrong? I checked for shorts or touching parts, reflow all the solder...

The orientation of the transistors should be alright, the transformer I suppose too.

 

[Toastman]

I had accidentally reversed the polarity of the DC jack, fixed it now.
Now when engaged there is hum that is controlled by the gain knob, volume and tone does nothing.

 

[mybud]

Have you biased the JFETs? Try adjusting the trimmers one at a time. Measure the drain voltage by connecting your DMM's black terminal to ground and use the other probe to measure the voltage on the drain of each JFET. A good starting point is 4.5V.

If you don't have a DMM, you can do this by ear. At some point you should get signal.

 

[Toastman]

I tried it already by ear, no guitar sound only hum. I'll try it with measuring
The gain knob affects the hum...

 

[mybud]

I tried it already by ear, no guitar sound only hum. I'll try it with measuring
The gain knob affects the hum...

Might also be worth reflowing the A10k pot joints, which look slightly funky.

 

[darwin999]

Might also be worth reflowing the A10k pot joints, which look slightly funky.

Agreed. And the same applies to the ground wire on the PCB (the one going to the stompswitch), plus some of the solder connections on the stompswitch itself.
Some other thoughts:

Definitely check J201 biases with a voltmeter, make sure those are properly connected and working ok.​

Have you double-checked the resistor values?​

Any chance the body of the A10K is touching/shorting connections on the underside of the PCB?​

​

 

[jwin615]

Also check D100 and the DC input cap.
Since you reversed polarity, they could be fried

 

[HamishR]

I think you need a better soldering iron. (Not being funny!) It looks like you either don't have a hot enough iron and/or the tip isn't clean or pointy enough. I suspect that will be a major part of your problem. I was having trouble getting good clean connections recently so bought a new tip for my iron and voila! Nice clean solder joints again.