SEX 3.0 Transport Damage - can't find the source

Y

yay

New member
Hey, my SEX  3.0 had to endure some damage during shipping, apparently someone thought it was a good idea to throw the package on the ground or something.
The wood case was broken, but no visible damage on the electronics. I fixed the case, and tried the amp with some cheap speakers (i should've checked the resistences first, ignore me being dumb!). It worked fine, but there was an imbalance in the output. I checked all the resistences, and this is the result:
https://docs.google.com/spreadsheets/d/1OgRru82lYEGJg7s2w0KMrTQqHbm1WGzVvfh4EakMXlE/edit?usp=sharing

I also took some pictures of the interior, so maybe someone can see some damage or weirdness that i have not been able to:
https://photos.app.goo.gl/wtrG8TiyoTsVlWTu1
 
Have you swapped tubes from side to side to see if the imbalance follows?
 
I have tested tube imbalance before. I would like to add that it's not a static imbalance. If i turn up the volume it almost doesn't change in one channel and get's normally louder in the other one.
It's much more obvious over speakers.
 
no, the other way around. right channel is much more silent, and reacts only very little to not at all to volume control. left channel works normally. i'm not 100% sure if right channel doesn't react at ALL to volume control or only very little, i think it's the 2nd.

i will post the DC voltages later today
 
The upper and lower lugs on the volume pot on the headphone jack side of the amp need to be temporarily shorted together, then see if the issue goes away.

If the issue is still present, remove that jumper and put it between the upper and lower middle lugs on the volume pot, then recheck.

If that didn't change the issue, remove that jumper and jumper pin 10 on each 12 pin socket together, then recheck.

If that didn't change the issue, remove that jumper and jumper pin 3 on each 12 pin socket together, then recheck.

If that didn't change the issue, remove that jumper and jumper terminal 3 to terminal 17, then recheck.

If that didn't change the issue, remove that jumper and jumper the upper and middle inside headphone jack terminals together, then recheck.

If that didn't change the issue, remove that jumper and jumper the upper and middle outside headphone jack terminals together, then recheck.

Do note that if you can download a 60Hz tone onto your phone and play that through your SEX amp, you can measure AC voltages at a few spots and we can debug your amp that way.

-PB
 
Well i'm retarded it seems, i misread your instructions and jumpered terminal 10 to 12 instead of pin 10!
It smelled of burning, i turned it off quickly and now there is a very weird sound in the right channel. Kind of scratching, random noises. Like random space noise or something...
 
Remove the jumper, do the voltage check, report any discrepancies.
 
2 82
3 19
4 0
5 0
6 420
7 422
10 398

16 87
17 20
18 0
19 0
20 404
21 422
24 398
h2,h5 3,48
h4,h7 3,29


got these voltages, seem to be the same as before



as to the checks with the jumper: when i did the check number one and two, was the sound supposed to only come out of the left channel? The left/right sound came only from left side, but with correct volume and even adjustment to the volume pot. I tested with left/right testing video on youtube.
 
yay said:
2 82
3 19
4 0
5 0
6 420
7 422
10 398

16 87
17 20
18 0
19 0
20 404
21 422
24 398
h2,h5 3,48
h4,h7 3,29
Click to expand...
There are no discrepancies between these voltages and the voltages in the manual.



yay said:
as to the checks with the jumper: when i did the check number one and two, was the sound supposed to only come out of the left channel? The left/right sound came only from left side, but with correct volume and even adjustment to the volume pot. I tested with left/right testing video on youtube.
Click to expand...
We are looking to resolve the imbalance in output.  That is your reported issue.  If you lost the right channel, that is a new issue. 
 
No, not as a new issue. That was what happened when i used the jumper positions in your suggested troubleshooting. (Before i made the mistake!)

These:
The upper and lower lugs on the volume pot on the headphone jack side of the amp need to be temporarily shorted together, then see if the issue goes away.

If the issue is still present, remove that jumper and put it between the upper and lower middle lugs on the volume pot, then recheck.
Click to expand...
 
I am unsure what happened exactly. When i opened the package, the wood base was split and the plate slightly bent (2mm maybe). I bent the plate back, and saw no damage on the electronics. The 100uF cap on the headphone jack side was bent, but i bent it back to it's correct position. No visible damage otherwise, no scratches on the inside or anything. They seem to have thrown the package, and the base just cracked.
 
I listed out 7 quick tests to do to see where the issue may be.  You've done 2 of them, could you do the next 5 and report your results?

-PB
 
Yes, ofc. I just stopped with the other tests since i damaged something whil doing test 3 wrongly.
Should i open another thread for that damage caused?
 
There aren't any voltage issues that I could see.  Please start over with the tests and let us know.  Also, if you are able to get a 60Hz tone fed into your SEX amp, we can use that to check on things as well.

-PB
 
I finally have some time to take care of this once and for all now.
I did the jumper tests, and this is my result:

The upper and lower lugs on the volume pot on the headphone jack side of the amp need to be temporarily shorted together, then see if the issue goes away.
-> Left and Right channel coming from only the left speaker, both the same volume and also the correct volume.

If the issue is still present, remove that jumper and put it between the upper and lower middle lugs on the volume pot, then recheck.
->  Left Channel coming from the Left Speaker, correct volume. Right Channel and Right Speaker no sound.

If that didn't change the issue, remove that jumper and jumper pin 10 on each 12 pin socket together, then recheck.
-> Left and Right channel coming from only the left speaker, both the same volume and also the correct volume.

If that didn't change the issue, remove that jumper and jumper pin 3 on each 12 pin socket together, then recheck.
-> Left and Right channel coming from only the left speaker, both the same volume and also the correct volume.

If that didn't change the issue, remove that jumper and jumper terminal 3 to terminal 17, then recheck.
-> Left and Right channel coming from only the left speaker, both the same volume and also the correct volume.

If that didn't change the issue, remove that jumper and jumper the upper and middle inside headphone jack terminals together, then recheck.
->  Left Channel coming from the Left Speaker, correct volume. Right Channel and Right Speaker no sound.

If that didn't change the issue, remove that jumper and jumper the upper and middle outside headphone jack terminals together, then recheck.
->  Left Channel coming from the Left Speaker, correct volume. Right Channel and Right Speaker no sound.
 
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