No work surfaces make me cranky. I'm still on the Intersound Mini-Six. My work surface for this particular project up to this point has been, I shit you not, a Hallicrafters S-53 sitting on top of the Lafayette U-50 standing on its side.
Here's an overlay of the circuit components I pulled out of the malfunctioning negative side of the +/- 12 volt power supply.
Here's a pulled trace from extracting the master volume control, not really an impediment, just annoying.
In plotting my approach to repair this unit, I've opted for simple regulation in the power supply. A regulator, instead of a discrete circuit. I'm going to learn what I can from the original circuit, but as a matter of course I'm taking the easy way out for now.
Turns out I didn't have TO-92 regulators on hand either, so the legs of a TO-220 are trimmed to fit.
Next step should be obvious..
So, I slapped a voltage regulator in and fired it up.
Lo and behold, there is now a negative voltage! However, it is less than 12 volts; and establishing a negative rail has pulled the positive rail down by several volts as well.
It was at this point that the ludicrousness of sitting on a box on top of a milk crate while working on a "table" that essentially boils down to a balancing act really sunk in. All tinkering is in stand-by while I sort out space issues.
Take care of your work-bench.