DSL40c red channel issue after modding. Can anyone help?

[ledvedder]

Hi guys! I'm hoping someone can help me out. I performed the Headfirst mods on my DSL. Now I'm having this issue. Green channel works perfectly, but the red channel has very low volume and barely any gain. Any ideas where to start with diagnosing this problem?

Here's a video of the issue,

Here's a video of the mods,

I've also uploaded a schematic of the mods.

 

[glpg80]

Going to need detailed pictures of your work as well. There’s no way to know from a sound clip alone.

First step in troubleshooting, is it’s time to get a voltmeter out and check that all preamp tubes have DC voltage and all cathode bias resistors have DC voltage. Check your work for solder shorts between components. Check for open/cold solder joints by pushing with a chopstick all of the components you added to see if sound comes back.

It is definitely possible to have a defective capacitor that is shorted which messes up everything like this.

 

[burger]

You've posted over in my FB group which is a good start, myself and the group there will help.