voltage issues

[robertb]

Hi everyone. Looking for help. My 15 year old son just put together the Reduction for me but we are having some voltage issues around one tube. The tubes light up but here are the problems:

18: 123 V
19: 15.6 V
20: 0 V
26: 123 V

I am attaching two pictures. Thanks in advance!

 

[Paul Birkeland]

What value is the resistor going to pin 7 on the offending side?  That doesn't look like a part we provided.

There's an LED that goes from the center pin of the 9 pin socket to pin 3 on each socket.  You are missing one of those.

 

[robertb]

The resistor is 220 ohms (it is the same as the resistor going to 1 and was provided with the kit).

We broke the LED trying to resolve the voltage issues. Do I need to replace the LED?

 

[Paul Birkeland]

Are you 100% sure about that resistor?

I see a color code that's orange, gray, orange, brown, and gold, which would be a 3.83K resistor, not a 220.

Yes, the kit won't work without all of its electronic parts installed.

 

[robertb]

I was actually wrong about the resistor. It is not a 220 but it came with the kit and we don’t have another 220. I need a new resistor (and a LED).

 

[robertb]

Thank you Paul for your expertise and sharp eye on a Sunday afternoon! We'll replace those parts and hope it'll resolve the issues!

 

[Paul Birkeland]

You can contact replacementparts(at)bottlehead(dot)com about getting some spare parts sent out. 

 

[Doc B]

It is a 220. That is not orange, gray, orange, brown, gold. That is red, a shadow of the end cap, red, brown, gold.

 

[robertb]

Any advice if that’s not the problem?

 

[Paul Birkeland]

You're right, looking at the second photo it's clearly a 220.

 

[robertb]

Would you please advise as to how we might resolve the voltage issues if the resistor is indeed correct? (The voltage issues preceded the broken LED)

 

[Paul Birkeland]

You need to install a new LED.  That voltage will never work properly without the LED installed in the circuit.  That LED provides 1.5V of bias to the cathode of that half of the 6922, and without that part present there is no bias voltage and no path for DC current to flow, hence the voltage issues.

 

[robertb]

Thanks. We will install the new LED once we receive it and repost as to the results.