LED out troubleshooting help

aphays · 1954

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Online oguinn

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Reply #15 on: June 14, 2019, 03:31:42 AM
To be fair, the way he has it is exactly how the manual has it
« Last Edit: June 14, 2019, 03:34:08 AM by oguinn »

Jameson O'Guinn

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Main System: Schiit Bifrost MB, Rega Planar 6 with Exact cartridge, Eros 2, BeePre, Kaiju/Stereomour II, Jagers, Mainline

Desktop System: Crack with Speedball


Offline Deluk

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Reply #16 on: June 15, 2019, 02:26:51 AM
My 1.0 Crack manual, and 3 board Speedball manual, shows it coming from the outside and that is how I built it. There may be new photos for the 1.1 Crack showing a different route but I can't think why it would be changed. It's much neater. Twisted greens used in the 1.1 along with the headphone jack resistor revision but other than that are there any actual changes?
I still have my 3 board Speedball to fit but I don't know if the later 2 board version required any changes to the basic Crack wiring.



Offline Paul Birkeland

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Reply #17 on: June 15, 2019, 06:06:14 AM
It's much neater.
???
 
The new wiring layout is far neater if executed according to the manual.  The red wire is now also out of the way for Speedball installation, or for the really common task of reheating the solder joints at 3L and 3U.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline aphays

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Reply #18 on: June 16, 2019, 05:41:34 PM
Okay - back home again. Same condition - turn amp on and everything is great for about 3 minutes, then the same LED goes off. Sometimes tapping around on it, or near it, or even on the chassis itself can make it come back on, but mostly tapping and banging does nothing. Once it goes off it stays off. I have tightened up as many connections as I thought might need it at this point, either heating them up or adding some solder. Still seems like I must have a loose one somewhere, and as the amp heats up it fails. That would seem to make sense to me with the timing always being quite similar. Below are the voltages I get with the LED on, and with the LED off. Do these confirm that this is the case? The issues are at terminal 1 and 7 primarily in terms of the voltages. The previous issue with terminal 10 has been resolved and no longer changes when the LED goes off. I've posted a few more pictures as well, but let me know if there are specifics areas I should zoom in on .

            LED on      LED off
1.)       80               149
2.)       173             166
3.)       0                 0
4.)       173             166
5.)       83                79

6.)       0                 0
7.)      104              148
8.)      0                  0
9.)      106              102
10.)    0                  0

Drew H.


Offline Deluk

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Reply #19 on: June 17, 2019, 12:52:01 AM
Point taken re the Speedball standoff install, I will have to tweak the red wire a fraction to move it sideways a little.



Offline Paul Birkeland

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Reply #20 on: June 17, 2019, 04:42:02 AM
Point taken re the Speedball standoff install, I will have to tweak the red wire a fraction to move it sideways a little.
I wouldn't move it.

2L needs to be reheated so that the solder flows into the hole of that terminal.

Since banging the chassis brings things back, I would try poking around with the wooden chopstick again to see if you can find which joint is causing this issue.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline elmoe

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Reply #21 on: June 17, 2019, 06:38:48 AM
Looks like 10U and 4L could use more solder



Offline aphays

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Reply #22 on: June 17, 2019, 10:38:10 AM
No dice - reheated 2L, problem still persists. Just out of curiosity, could this condition occur due to a bad component? I realize that a bad solder is much more likely, but is it possible that one of the resistors or capacitors was damaged by a short due to a bad connection early on that is now fixed? The first bad solder I found was at 20U, and I found it becuase I saw it spark. Could that have damaged either the resistors or the capicitor that are connected there?

Drew H.


Offline Paul Birkeland

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Reply #23 on: June 17, 2019, 01:04:05 PM
No dice - reheated 2L, problem still persists. Just out of curiosity, could this condition occur due to a bad component?
This is exceptionally unlikely.

I realize that a bad solder is much more likely, but is it possible that one of the resistors or capacitors was damaged by a short due to a bad connection early on that is now fixed?
No, this would give a completely different set of problems.
The first bad solder I found was at 20U, and I found it becuase I saw it spark. Could that have damaged either the resistors or the capicitor that are connected there?
No.

I'm sorry to say but when you tap on the chassis and that restores operation, that means you have a joint that isn't well connected.  We recommend poking around with a wooden chopstick to determine where this joint is so you can effect repairs.  I don't mean to sound like a broken record, but when I'm finished with a build, I will knock on it really hard to see if and LEDs shut off as a way to test that the joints are secure.  You have a loose wire, or a bad solder joint, or a broken wire somewhere in your amp. 

A shorted capacitor will cause billowing smoke and terrible stench from your amplifier.  You do not have that. 

A shorted resistor will either raise the B+ a little if it's one of the 270 ohm resistors, burn the 270 ohm resistors up entirely if the 270K shorts, red plate and draw the B+ down if one of the 3K resistors shorts, or leave high voltage at terminals 1/5 with the LEDs lit if one of the 22.1K resistors shorts.

Keep poking around with the chopstick at everything that has a solder joint.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline aphays

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Reply #24 on: June 17, 2019, 01:18:49 PM
Will do. Thanks man. This definitely helps clarify things.

Drew H.


Offline aphays

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Reply #25 on: August 16, 2019, 08:03:34 AM
Just wanted to follow up, as I finally got this sorted. Traveled and was working much of the summer, so I had to put this down for a while. I must have gone over every soldered connection in the amp 3 or 4 times to no avail. Replaced the LED's, no change. Over time I became suspicious that the issue was in the area of A8. Finally decided it had to be a bad 12au7 tube or a bad socket connection. Ordered both. Tube arrived first. Replaced it. Amp is working great. Both LED's come on together now instead of in a staggered delay. And they stay on. So glad to finally get this sorted out! Can't believe it took me that long to figure out it was an issue with the tube itself. Now finally looking forward to just listening.

Drew H.