Channel imbalance on fine attenuator [solved]

[Loquah]

I don't recall the position of the switch when I took these measurements (it was late last night). I'll recheck with the methods discussed and confirm.

[Loquah]

Thanks for the heads-up. When in the circuit, the readings are as previously reported (22.6 vs 11. while out of the circuit, both resistors read the same. Now I have to find why the resistor on the "C" side of the fine attenuator is reading the same in and out of the circuit.

[Paul Birkeland]

There's really a lot of solder on all your joints, it's entirely possible that you melted the switch a bit when making these connections, and that this particular resistor is not making contact. (Notice in the manual how you can still see through each switch solder lug) You can put the switch back on that -3dB position and look for continuity from the lower switch lugs to the lugs that hold the 22.6K resistors.

[Loquah]

Thanks for the input everyone.

Regarding the solder quantity, I ran out of my favourite solder and used some other solder I had which ran a lot faster than I'm used to, but thankfully that wasn't the issue.

Thanks to the comments about the resistor readings changing when in or out of the circuit, I was able to isolate the issue to the C side resistor on the -3dB contact. The issue was a poor solder joint where one resistor lead on the terminal was soldered properly, but the one in question had a void around it. I reflowed the joint and all is well!

Thanks as always for the advice and knowledge!

[Doc B.]

Once again this is why we suggest simply reheating all the solder joints before trying to troubleshoot a problem on a component by component basis. It can be a significant time saver.

[Loquah]

Yeah. I visually inspected them all (not close enough apparently), but didn't reheat every one. Sorry for the wasted time!