Right Channel Issue, Continued...

[Paul Birkeland]

Recheck your voltages and resistances.

[Natural Sound]

Jameson, sorry if this is obvious but did you try swapping the tubes from left to right? Also, I've had a few 6FJ7's with steel pins that were kind of cruddy. Sometimes removing and replacing the tube solves this. Other times I've used Doc B's' "Cotton Swab chucked into an electric drill with a little metal polish trick" to clean up the nastier oxide examples.

I wouldn't go "ripping anything out" at this point if I were you. A more systematic troubleshooting approach like PB has been helping you with makes more sense.

[oguinn]

Resistances were all good. Right input pin was 93.2K, left was 94.8K.

Voltages were also good:

Terminal	Manual	Observed
2	65-95	80.2
3	15-18	18.8
4/5	0	0
6	385	378
7	400	406
10	380	383
16	65-95	79.5
17	15-18	16.8
18/19	0	0
20	385	384
21	400	410
24	380	390
H2, H5	+/-2.8-3.2	3.3, 3.31
H4, H7	+/-2.8-3.2	-3.13, -3.14

[oguinn]

Jameson, sorry if this is obvious but did you try swapping the tubes from left to right? Also, I've had a few 6FJ7's with steel pins that were kind of cruddy. Sometimes removing and replacing the tube solves this. Other times I've used Doc B's' "Cotton Swab chucked into an electric drill with a little metal polish trick" to clean up the nastier oxide examples.

I wouldn't go "ripping anything out" at this point if I were you. A more systematic troubleshooting approach like PB has been helping you with makes more sense.

I was a slight bit dramatic. I’m a little frustrated after having been at this a few hours.

It hadn’t followed the tube when I checked yesterday, but I didn’t try again yet. I’m give it another go tomorrow

[Paul Birkeland]

If that doesn't resolve it, let us know and I can write up a set of instructions for installing jumpers through the amp.  This should at least narrow down the problem area.  I can also give instructions for tracing a 60Hz AC signal through your amp with your multimeter.

-PB

[oguinn]

Ok, confirmed that the issue does not follow the tube. What are my next set of options?

[Paul Birkeland]

Play a 60Hz tone into your SEX at full volume from your phone.  Measure the AC voltage between ground and the center pin on each level of the pot with the pot all the way up, then half way up. Report those values here.  The SEX does not need to be on for this set of measurements.

[oguinn]

Alright. This is where we start to see the seams of what I know.

I took a series of measurements because I was unsure how to get at what you're looking for. It's possible my multimeter might not be up to snuff. Attached is a picture of the dial.

See the attached photo for a key of the multimeter settings.

Setting 1 (I believe this to be AC volts, but the lowest setting I have is 200V):

Reading	Right	Left
50%	00.1	00.2
100%	00.1	00.2

Setting 2 (I believe this isn't what you're looking for; this seems like DC amperage):

Reading	Right	Left
50%	2.7	5.2
100%	2.7	5.2

Setting 3 (This is DC voltage, again not what you asked for):

Reading	Right	Left
50%	Ranged from 0 to 0.4	1.5
100%	Ranged from 0 to 0.4	1.5

[oguinn]

Attaching the photo again here. It didn't work last time.

[Paul Birkeland]

While your meter is totally accurate for checking DC voltages in our kits, that AC scale doesn't go down low enough.  The ~$20 meter at Hazard Fraught is going to be really helpful for this debugging:
Meter
This meter with a set of $30 Fluke probes is the best meter you can get for $50.

While the probes aren't so wonderful, the actual meter is excellent.  On the 2V AC setting, you should get a much clearer reading of those levels.

[oguinn]

I was definitely fearing/anticipating that response when I saw AC only went to 200V. I'll get a new one ordered and chalk it up to lack of experience. Thanks!

[oguinn]

Alright, ordered a new multimeter from Amazon that goes down to 600mv AC. Picked the Amazon one (and some new leads) because of overnight shipping. We'll kick this pig tomorrow. Thanks, PB.

[Paul Birkeland]

Which one did you get?  I like to try to have a few recommendations when people ask.

[oguinn]

This multimeter (AstroAI WH5000A) and these leads (AstroAI leads with alligator clips and others).

[oguinn]

Ok. Got the new multimeter. With the black lead clipped to the ground buss and the red lead clipped to the middle pin of the output jacks, I get:

Right: 403.5 mV
Left: 402.6 mV

I did not notice a difference when changing the pot position.