Voltage checks - puzzled and… UPDATE: operator error. I don’t deserve this amp

[e2o]

Here is a video of 1-10 begin tested. UPDATED:this video shows the meter in 200 V range setting. All of the “1__.” Results are over voltage. See new post below for results with meter in 600 V range.



Note: I take your advice and instruction on safety very seriously. I'm not using a clamp here because I purchased the leads with clamps for my new fancy meter, and that thing is giving me really odd results as stated above.

[e2o]

Oh, and a glow test...

[e2o]

OH! Wait. I changed my range from 200 to 600, and now I get readings:

Terminal  ||  Voltage Expected  ||  Voltage Measured
1  ||  50-100  ||  171
2  ||  170  ||  383
3  ||  0  ||  0
4  ||  170  ||  383
5  ||  50-100  ||  168
6  ||  0  ||  0
7  ||  90-115  ||  232
8  ||  0  ||  0
9  ||  90-115  ||  232
10||  0  ||  0

[e2o]

Just went back and quadrupled my checks on the power line voltage testing: 119.3 V
So I used instructions for "If you voltage is greater than 115 and less than 130.
I checked again the Power Transformer Input Wiring.
I checked again the Power Transformer Secondary Test:
7 <--> 9 = 5.6 (expected 6.5 +/- 20%)  (note: fancier meter reading 6.13)
11 <--> 12 = 166.8 (expected 175 +/- 20%)  (note: fancier meter reading 169.1)

[Paul Birkeland]

You have a loose ground wire in your amp.  This is absolutely consistent with seeing something nonsensical in your voltage checks like ~400V where you should have 200V.

You need to reflow all of the solder joints where there are black wires from the RCA jacks through the volume pot, the volume pot to terminal 3, terminal 3 to the headphone jack, the headphone jack back to the 6 lug strips, and between the terminals on the 6 lug strips.

It is extremely common to have a loose black wire at the headphone jack and have the exact symptoms you're describing, so please quadruple check that.

[e2o]

Thanks!! On it…

[e2o]

Ok, if it was black, it got wicked, inspected and re-soldered. Nothing looked loose, un-crimped, or chalky. Everything back together and readings are the same as above. Symmetrical, steady, same.
171, 383, 0, 383, 168 for 1-5;
0, 232, 0, 232, 0 for 6-10.

Another meter should be arriving tomorrow for verification.

Until then, anything in the physical assembly I should check?

Thanks,

- eric

[e2o]

OMG. As I posted in the update to the original post … I’ve been doing voltage readings in AC volts!! While browsing some other forum posts, I ran across a moderator comment asking another builder if that’s what they might be doing. OH THE SHAME!!!

I just sssumed “well that’s what comes out of the wall…(!)”

Thanks SO much to Paul Birkeland and Doc B. - you guys are awesome.

BY the way - it sounds absolutely lovely!

[Paul Birkeland]

Oh that's strange, usually the AC setting will read things really low.  I'm glad you got it figured out.

[Mucker]

Way to go getting it sorted out. Now go enjoy the awesomeness of the Crack!