Build Your Own Clone Message Board

I haven't posted here is almost a year! First year of teaching middle school science kept me busy.

I finished building the Triboost about 3 weeks ago, and everything worked perfectly except no sound out of the Linear boost (middle rotary). I traced down everything on the schematic, reflowed everything and replaced all the components in the linear boost section and still nothing.

I've pulled and replaced all the resistors, the tranny and the .1 caps in the circuit.
The LED lights properly (right color for each position.
The clean and GE boost work great.
But for the life of me I can't figure out the linear boost problem. My last resort is to pull the rotary switch.

Any thoughts?

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Gear:
Custom strat
Squire Classic Vibe Tele (I love this thing!)
Hand-wired tweed champ from Tubedepot
DIY effects

Since it is such a simple circuit and you have replaced all the parts it would seem to be the switch that is the problem. Off hand I don't know if how you set up the switch indexing and / or orient the switch in the PCB could cause a problem. Might be worth checking.

You could - set the switch for linear (with the circuit un-powered) and use a multimeter to check you have continuity across the two related switch sections.
- solder in some temporary jumper wires across the switch to see if the linear boost then comes to life
or - use an audio probe to trace the signal through the circuit to see where it gets lost.

Might also be worth measuring the voltages on the collector, base and emitter of the 2N5088 and reporting those.