Resistance Checks help

deltaray · 3109

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Offline deltaray

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Reply #15 on: September 24, 2018, 04:16:08 AM
Alright, have check and resoldered the joints joint along the ground buss. 

The voltages remeasured are as follows
1. 85V
2. 184V
3. 0.5V
4. 184V
5. 81V

6. 0.4V
7. 116V
8. 0.7V
9. 111V
10. 0.3V

Doesn't seem like there is much change in the measurement.



Offline Paul Birkeland

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Reply #16 on: September 24, 2018, 04:39:11 AM
You could try posting some additional photos of the build.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline deltaray

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Reply #17 on: September 24, 2018, 03:47:22 PM
Having difficulties putting the images up on the forum, tried 5-6 times.

Anyway follow this link for the build images
https://imgur.com/a/pAJfeoO



Offline Paul Birkeland

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Reply #18 on: September 24, 2018, 05:21:55 PM
1.  Your UF4007 diode bridge scares me a little.  The instructions in the manual are extremely specific, I would revisit that a little bit.
2.  13U could use more solder.
3.  3L is not all the way soldered.
4.  B1 and B4 don't look all the way soldered.
5.  2U is poorly soldered.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline deltaray

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Reply #19 on: September 29, 2018, 10:38:33 PM
ok revisited the points you addressed. actually added the speedball upgrade.

There is still a imbalance leaning towards the left. tracks where guitar is clear right, now appear in the middle.

is the similar problems with either the tubes or pots? looking up the other threads.

I've added the pictures now, do let me know if you need more images.

OA - 76.1V
OB - 71V < is the voltage here suppose to match OA?
G - 0.6V
B+ - 196V



Deke609

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Reply #20 on: September 30, 2018, 03:04:12 AM
Deltaray - Sorry to hear about your channel imbalance issue.

I took a quick glance at your photos.  Your wiring layout appears pretty good, but some of the solder joints are iffy.

20 and 21 look like classic cold solder joints.  I would try reheating both of them until all the solder turns liquid, and then leave the soldering iron on them another 1-2 seconds or so until you see the solder flow into the joint.

I wonder whether the soldering issues are a function of your soldering iron? If your are using an iron with a large chisel point (or any large tip), that could make it difficult to make good contact. Unfortunately, most single-tip fixed wattage soldering irons come with such tips. I find large-tipped soldering points unusable for projects like this and instead use a soldering tip that is no more than 2mm (approx. 1/16 inch) wide at the tip.  It works great.

Hope you getting it working soon.






Offline Paul Birkeland

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Reply #21 on: September 30, 2018, 01:38:13 PM
I'd be interested in seeing the joints on your headphone jack.

OA and OB on the front board do not need to match.  Having said that, if one value is way, way different than the other, then that could indicated that half of the 12AU7 isn't functioning properly, but your voltages are spot on.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline deltaray

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Reply #22 on: September 30, 2018, 02:02:40 PM
Sure. I've added the RCAs in case you may want to look at them.

Thank you!



Offline deltaray

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Reply #23 on: October 05, 2018, 03:06:52 AM
Turns out the culprit here was the ge 6080 tube. I managed to get my hands on a tungsol 6080. I did an ABA and it was quite apparent, that the ge one was a bit off centred to the left!



Offline Paul Birkeland

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Reply #24 on: October 05, 2018, 05:23:20 AM
Are you sure that these terminals aren't touching?

In the past, we have seen folks replace tubes, declare an issue resolved, the return later when the issue reappeared with the different tube.  Often times the act of removing and reinserting a tube into a socket can nudge a loose connection enough to get things working properly for a short time.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline deltaray

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Reply #25 on: October 05, 2018, 03:46:06 PM
yes, they are not touching, in fact the image above that image you have taken to circle would show that they are not connected. I am post two more image for clarity.

as for the tubes, i have swapped them about repeatedly to do this comparison.

I have already posted some images on the voltage measurements and images of the board above, so do let me know if i need to furnish more information.