Electronics Gurus!

[rich83]

Ok.. here goes!

One of the LEDs has broken on my nixie clock.



Ive measured the voltage across the legs of the diodes. All measure 2.7-2.8V apart from the one that broken with reads about 1.4V.

Does this mean that its not illuminating becuase the voltage is too low, or is the low voltage reading a result of the broken diode?

Thanks
Rich

[Hedge]

Sounds like it's not illuminating because the voltage is too low.

[rich83]

Hmmm... i just dont see why its not getting the voltage. As you can see they are all connected up in parallel so if one wasn't working due to a voltage problem i would imagine none of them would work.

 Need to take it to bits properly tomorrow to check for dry joints.

[PDT]

Are you measuring the voltage with the diode still connected? If so, disconnect the diode and measure voltage.

[rich83]

Yes the diode is still connected up.

[Hedge]

If it's the blue LED then it could just be the diode that's failed.

[rich83]

Hedge.. D11-D16 on that diagram are the LEDs

[PDT]

In that case its the diode pulling the voltage down.

[cmdrfire]

Do you have a multimeter?
What resistance do you measure across the resistor? Check also for conduction across the LED if you have multimeter that can do diodes.

Unlikely to be an LED failed unless it's been subject to high temperature for an excessive time while you were soldering (which can result in an eventual failure); more likely cause is a dry joint I'd guess.

edited 'cos i didn't see you measured voltage across the LED

[Hedge]

Hedge.. D11-D16 on that diagram are the LEDs

I know. 

[rich83]

Do you have a multimeter?
What resistance do you measure across the resistor? Check also for conduction across the LED if you have multimeter that can do diodes.

Unlikely to be an LED failed unless it's been subject to high temperature for an excessive time while you were soldering (which can result in an eventual failure); more likely cause is a dry joint I'd guess.

edited 'cos i didn't see you measured voltage across the LED

Tested all LEDs with the Diode setting. The one that is broken gives a reading about  300... the working ones read 1500ish

Sorry hedge... internetz missunderstanding! 

Rich

[Janner_Sy]

im no electronics guru, i do big power, but ive dabbled with elctronics at Uni, id bet its as PDT says,  to much heat cause and a poor connection/solder issue and will cause a volt drop over that diode.  

[cmdrfire]

Do you have a multimeter?
What resistance do you measure across the resistor? Check also for conduction across the LED if you have multimeter that can do diodes.

Unlikely to be an LED failed unless it's been subject to high temperature for an excessive time while you were soldering (which can result in an eventual failure); more likely cause is a dry joint I'd guess.

edited 'cos i didn't see you measured voltage across the LED

Tested all LEDs with the Diode setting. The one that is broken gives a reading about  300... the working ones read 1500ish

Sorry hedge... internetz missunderstanding! 

Rich

Solution replace LED

[JackG]

Ok, what the hell is that clock all about??? I want one......but there expensive! Seem to be half built on eBay? Why does it look so funny?? 

[rich83]

Thank neo.  Must have just been a dodgy component.

JackG... What the hells is it all about??? Its a clock!    (i saw cmdrfires and had to have one)

Rich