Weird Voltage Readings, LED and Tube problems

[Doc B]

New member Nightloyd is having some issues starting a new thread, so I have initiated it for him.

 

[Nightloyd]

Thanks for the help Doc B. !

Hello Bottlehead forum members,
So i got my Crack OTL with the 240VAC and i assembled it yesterday.
My first problem was that the rocker switch melted which led to that it didn't work at all. I solved it by circumventing the switch.
I should also note that all Ohm readings were correct.

Now to the problem i have at the moment:
I get alot of bad voltage readings (Se list below).
The 2 LED's dosen't light up.
And the last problem i have noticed is that the 12AU7 Tube lights up and gets warm but the 6080/6AS7 Tube dosen't.

Voltage Readings:
Terminal - My reading - Expected reading

2 - 225 - 170
4 - 225 - 170
5 - 27 - 90
7 - 27 - 100
9 - 0 - 100
13 - 225 - 170
15 - 0 - 185

A1 - 27 - 90
A3 - 0 - 1,5
A7 - 180 - 0
A8 - 18 - 1,5


B1 - 228 - 90
B2 - 229 - 170
B3 - 27 - 100
B4 - 27 - 90
B5 - 230 - 170
B6 - 0 - 100

Here are some pictues of how i assemlbed it:





I hope you guys can help me out with solving this.
/Nightloyd

 

[Scratch_P]

It appears your octal socket is flipped.  The gap should face the front.

Shawn

 

[Nightloyd]

It appears your octal socket is flipped.  The gap should face the front.

Shawn

Thank you so much for the help, i get correct readings on everything now.

But i don't get any sound in the right channel and one of the LED's don't glow.
Does this mean that the LED is broken?

 

[Grainger49]

Don't feel bad.  That is just the kind of thing I would do and I've been at this a long, long time.  Trust me, you are in good company.

Check the orientation of the LEDs first.  They are a booger to get right.  Yes, they can be broken but are most often put in backward.  They don't light backward.

 

[Nightloyd]

Don't feel bad.  That is just the kind of thing I would do and I've been at this a long, long time.  Trust me, you are in good company.

Check the orientation of the LEDs first.  They are a booger to get right.  Yes, they can be broken but are most often put in backward.  They don't light backward.

I checked and the the stripe is toward the center.
Maybe i should say that it's the LED connected to A8.

 

[Grainger49]

Ok, the banded end is the "cathode" which means it should go toward ground.  It sounds like it is right.  

What is the voltage at A6 and A8?  These voltages should be off since the right channel is not conducting.

 

[Nightloyd]

Ok, the banded end is the "cathode" which means it should go toward ground.  It sounds like it is right.  

What is the voltage at A6 and A8?  These voltages should be off since the right channel is not conducting.

Okey i have no mesured the voltage of A6 and A8
A6: 143V
A8: 11,7V

And it should be like this:
A6: 90V
A8: 1.5V

And that's way off, i guess this means that i need to replace the LED?

 

[Grainger49]

I expected A6, the plate, to be higher voltage than specified but didn't expect A8 to be high also.  This is looking at the second triode in the tube.

When the tube doesn't conduct, or turn on, the plate has higher voltage on it because it isn't passing current through the tube.  But the 11.7V on the cathode, A8, is odd.

Doc, Paul, Paul?

 

[Paul Joppa]

Usually, a high cathode voltage indicates the LED is backwards. Sometimes it is not connected (bad solder joint), or it is just soldered to the wrong terminal. In any case, it is not conducting current from A8 to ground.

 

[Grainger49]

Does the high voltage also happen if it is damaged, open?

 

[Nightloyd]

Usually, a high cathode voltage indicates the LED is backwards. Sometimes it is not connected (bad solder joint), or it is just soldered to the wrong terminal. In any case, it is not conducting current from A8 to ground.

Does the high voltage also happen if it is damaged, open?

Can i replace the LED with anykind of LED?
Or does it have to be the HLMP-6000?

 

[Laudanum]

I dont know where you are but Farnell has them ... http://uk.farnell.com/avago-technologies/hlmp-6000/led-submin-red/dp/1003184

The Queen will send replacements out to you for free but being overseas, it may not be as quick.  Depends on how anxious you are I guess.

 

[Nightloyd]

I dont know where you are but Farnell has them ... http://uk.farnell.com/avago-technologies/hlmp-6000/led-submin-red/dp/1003184

The Queen will send replacements out to you for free but being overseas, it may not be as quick.  Depends on how anxious you are I guess.

I saw that Farnell had them in Sweden too (i live in Sweden), but could i use another LED instead that's goes to about 3V? Or would that shorten the lifespan or destroy the Crack?