No LED high voltage on pin 5 and 9

[PaulWogan]

I have just finished building my Crack. The initial voltage tests from the power supply come out normal, and the resistance checks did as well. The tube glow test passed as well. With the final voltage check I notice a high voltage on pin 5 and pin 9. And the LEDs are both not lighting up.

actual (recommended) voltage measured at pins

1: 98v (50-100v)
2. 174v (170v)
3. 0v (0v)
4 174v (170v)
5. 157v (50-100v)
6. 0v (0v)
7. 90v (50-100v)
8. 0v (0v)
9. 156v (90-115v)
10. 0v (0v)

I tested both LED for resistance (both directions), nothing there. The 3k resistors both measure about 2.9k

I read most of the related posts on LEDs not working and high voltages on pin 5 and 9. I've double checked all solders and resistances. I cleaned off the pins on the 6800.

I read some difference between 110v and 240v transformers, but didn't see this as an option when ordering. I'm running the unit in Spain on 232V ac

Do you have any other suggestions ? Did I blow the LEDs when soldering?

Thank you in advance for any troubleshooting steps.

 

[Paul Birkeland]

On the 9 pin socket, look at pins 6 and 7.  They look like they are almost touching.  You really don't want these to touch, so trim those leads back!

The paragraph on the bottom of page 20 that's in bright red explains what we mean when we say "attach".  It does not mean to slip a wire or lead through a terminal and just leave it there.  You need to bend the leads around the terminals to make a mechanical connection before soldering.  You have lots of wires and leads just resting inside terminals, so I would go back through and bend the free ends up against the terminal strips and tube socket pins, then reflow your solder joints. 

I would also be extra careful that both black wires that attach to the headphone jack are captured by solder.

 

[Thermioniclife]

You are also missing the wire from A1 to 5U

 

[PaulWogan]

Thank you both for the quick response. Awesome. Can't believe I missed the wire. With the wire the voltages look within range and the LEDs come on.

I will resolder the connections next after attaching the wires properly.

I do notice a hum on the headset, could this be the solder joints? Or other thoughts?

 

[Thermioniclife]

Yes poor connections can cause hum. Poor connections at the power supply capacitors can cause hum.

 

[Paul Birkeland]

Thank you both for the quick response. Awesome. Can't believe I missed the wire. With the wire the voltages look within range and the LEDs come on.

That missing wire would only prevent one LED from glowing.  The bad voltage on terminal 1 with your initial measurements tells me there are still other issues.

 

[PaulWogan]

I'm heeding your advice and I will resolder all connections over the next few days to remove the hum. Poor connections make sense.

Voltage wise this where things are at at the moment:

actual (recommended) voltage measured at pins

1: 98v (50-100v)
2. 182.3v (170v)
3. 0v (0v)
4 182.1v (170v)
5. 83.9v (50-100v)
6. 0v (0v)
7. 116v (50-100v)
8. 0v (0v)
9. 107.9v (90-115v)
10. 0v (0v)

I really appreciate all the help and advice! Will double the double-checking and re-re-read the instructions once I get to the speedball part for sure!

 

[Paul Birkeland]

You're moving closer to what's correct.  I would imagine your LEDs on the 9 pin socket are now lighting up at least.