No smoke but a few adjustments needed, the gnd scheme always catches me out!!
This case isnt ideal but I’ve drilled 3 holes in the front so the two parts of the case are grounded together.
Will sort the polarity switch just before the output.
Having some trouble with ch1, only getting 0.543v to collector of TR3 and low level output of ch2, I suspect it’s the txf at fault or a stray connection to gnd?
I suspect a short on B from the txf, I will disconnect the txf at B and see, check continuity, it’s either that or the R3 68k resistor!!
I was getting 24v on all primaries of output txf and meant to get less on B as it should be dropping the voltage down to about 20v?
Both channels working now, cold solder joint on txf of ch1, just need to adjust gain setup now by tweaking the 91R resistor on U/V of the b284 pcb to level match both channels. Less resistance more gain obviously, R10 390R + 100R trimmer then I’ll just dial it down to level match both channels.
Couple of issues, one with channel B not having the same gain as channel A and I don’t seem to be able to adjust the gain with adjusting the 91R down in resistance?
Also on one channel on pin2 I’m getting 5.2v and pin 3 only 1.2v? Again could be a txf issue need to trace and find out where it’s going wrong.
48v all working fine.
Another little gnd issue I need to sort as well, so not quite home and dry!!