Crack LED issue
- Thread starter barnstead
- Start date
Those are working voltages.
Drew1d
New member
I'm uncertain if you're still having the problem, the last thing you said was the other one isn't lighting, but the subject says the issue is resolved.
So, diodes are like one way streets right? And when electricity is running through it, it lights up. Now, I don't have a lot of experience with LEDs, but I would say that a bad diode would conduct electricity both ways.
If it was hooked up backwards for example, I wouldn't expect it to light up. (unless blown, though....I've never tried it.) I would expect that to be the most common error, although the picture looks right.
The other not lighting up problems would be from electricity not running through it, like,
- one side is not connected
- something internal to the piece is no longer connected
Assuming that the tube is fine, and it's the same one as before. They are "keyed" so you can only put that in one type of way. If you were using the same LEDs, and moved one to the other side when replacing the socket, then I would say there is probably some internal break in it.
Let's say that you got all new parts. I mean...it's possible that you got two bum parts, either the sockets or LEDs, but that seems unlikely.
I would take like a AA battery, and clip or tape a wire to each side of it. Now, with those two wires, touch the positive side (the nipple side) to the pin of the socket, and the negative side to the center of the socket, did it light up? Do the same to the other LED, does it light up?
So, diodes are like one way streets right? And when electricity is running through it, it lights up. Now, I don't have a lot of experience with LEDs, but I would say that a bad diode would conduct electricity both ways.
If it was hooked up backwards for example, I wouldn't expect it to light up. (unless blown, though....I've never tried it.) I would expect that to be the most common error, although the picture looks right.
The other not lighting up problems would be from electricity not running through it, like,
- one side is not connected
- something internal to the piece is no longer connected
Assuming that the tube is fine, and it's the same one as before. They are "keyed" so you can only put that in one type of way. If you were using the same LEDs, and moved one to the other side when replacing the socket, then I would say there is probably some internal break in it.
Let's say that you got all new parts. I mean...it's possible that you got two bum parts, either the sockets or LEDs, but that seems unlikely.
I would take like a AA battery, and clip or tape a wire to each side of it. Now, with those two wires, touch the positive side (the nipple side) to the pin of the socket, and the negative side to the center of the socket, did it light up? Do the same to the other LED, does it light up?
Paul, by current voltages do you mean the wall voltage? It's 120.4 volts. If not I may need a bit more guidance.
Not sure how this got marked resolved, it's still unresolved. Drew, can confirm both LEDs are functional, they were tested before I attached them to the new socket.
Not sure how this got marked resolved, it's still unresolved. Drew, can confirm both LEDs are functional, they were tested before I attached them to the new socket.
The voltages you posted are correct and consistent with a working amplifier, I didn't notice that you said the A3 LED wasn't lighting up. What DC voltage do you see at A3 now?
Reflow the joint at A5 and add a little extra solder.
Drew1d
New member
OK dude it can only be so many things. I think that you need to check the LED while it’s in the circuit not before. Try the battery test with the LED and see if it lights up. ( make sure the amp is unplugged and discharged ). If it lights up also check the LED with the tube plugged in. Perhaps when the pins wiggle when the tube is plugged in, it is breaking its connection. If that still lights up take the tube out and jam the wire into the socket and test. If that lights up replace the tube. Test the working side also to make sure your testing methods are sound. Is it possible that it is lighting up and the room is too bright? Does the amplifier work at all, or just one side? ( use crappy headphones to check, and not in your ears).
Not killing yourself, but you could test the voltage of the pins where each each led connects, while the amp is on. They should be similar and only a few volts. Being extremely careful, because the high voltage pins are next to it. Like, alligator clip before the amp is on, and turning the amp on/off by plugging it into the wall outlet. Black side to ground, red side to pin. I do the left hand in pocket, negative black side of the meter touching the metal chassis, and the red probe carefully touching the pin. Test one led then the other, same as above. But danger is my middle name, and I don’t recommend that to anyone not experienced.
Not killing yourself, but you could test the voltage of the pins where each each led connects, while the amp is on. They should be similar and only a few volts. Being extremely careful, because the high voltage pins are next to it. Like, alligator clip before the amp is on, and turning the amp on/off by plugging it into the wall outlet. Black side to ground, red side to pin. I do the left hand in pocket, negative black side of the meter touching the metal chassis, and the red probe carefully touching the pin. Test one led then the other, same as above. But danger is my middle name, and I don’t recommend that to anyone not experienced.
Reflow terminals 4 and 5, both upper and lower.
The low voltage across the LEDs means not a lot of current is being drawn across it, but you have the correct current being dropped across the 22K resistor on that side of the amp. This could be caused by a flaky solder joint at A4/A5 making half the tube not heat up properly, or possibly a different loose solder joint in the amp, or even the lugs on the pot where the black wires connect may not be well soldered.
You're close to having a working amp, really you should just reflow all the solder joints in the amp other than the power switch and LEDs just to be certain they are all solid.
You're close to having a working amp, really you should just reflow all the solder joints in the amp other than the power switch and LEDs just to be certain they are all solid.
Can you post some fresh photos of your build as it sits now?
I still see some questionable solder joints in the amp. The wiring around B7/B8 makes it look like one of the green wires is going to B6 instead, but that isn't the case is it?
Well, you could send this one in for repairs if you'd like. You would need to contact queen(at)bottlehead(dot)com to request this, being sure to mention that you've been working with me here.
There is very, very likely a flaky solder joint or two at work here.
There is very, very likely a flaky solder joint or two at work here.
