Interesting results, Bob: at the DAC calibration step, only Effects Speed makes Leds 1 light up to 4 (in the very first values near Min), all the while LED 5 staying put, and this only when Cutoff is at 0. If I put Cutoff at Max, then the LEDs stay at 1 & 5 On.
I reckoned from the Service Manual that VR 7 makes the two LEDs 'open sideways' until they reach 1 & 8, so I used FX Speed to set the LEDs 4 & 5 ON, and the turned VR7 (which I had reflowed and continuity-tested recently), and it does work.
So, both VR7 and VR6 do work, it's just there's an issue at or near the line which deals with LED 5 onwards.
Any thoughts?
Yash