Terminal 1 resistance reading 0 [resolved]

[Jackie.tang]

Hey y'all!

I've recently finished building my crack, and moved on to final resistance checks. All the other terminals are checking out ok, but terminal 1 is returning a reading of 0 ohms.

Attached below is a photo of the kit

Not sure what to do. Any suggestions?

 

[Paul Birkeland]

The green wire going to terminals A4 and A5 is touching terminal A6.  This will make the magic smoke come out if you power up this Crack.

 

[Jackie.tang]

Can you clarify what you mean by that? I dont see a green wire on terminal 6

 

[Jackie.tang]

The issue seems to have resolved itself after randomly resolderimg any joints I could think of related to Terminal 1. I have a new issue now though, the voltages at Terminal 5 and 9 are 150 V when the manual specifies 50-100 and 90- 115 respectively. All the other voltages check out.

1. 55.6 V              6. 0 V
2. 168 V              7. 87.7 V
3. 0 V                    8. 0 V
4. 168 V              9. 150.5
5.151.2 V          10. 0 V

Any thoughts on where those issues are coming from, or are those within tolerances?

 

[Paul Birkeland]

Solder joints and mechanical connections.

If the green wire going to A4/A5 touches A6, you will get additional problems.  Please fix that and don't turn the amp back on before you do.


When you have fixed that, please report the DC voltage on A3. Also are both halves of the 12AU7 glowing?

 

[Jackie.tang]

I've moved the wire a bit further from A6, they are not touching.
Both halves of the 12AU7 are glowing. The DC voltage on A3 reads 18.4 V

 

[Paul Birkeland]

You can temporarily install a wire jumper between A3 and A8.  The LED at A3 has been damaged by either being touched by a soldering iron or from excessive heat.

 

[Jackie.tang]

Would you by any chance have a photo of what the finished product looks like with the jumper wire? I have a couple from an arduino kit but they're pretty long for how short the gap is

 

[Paul Birkeland]

Take a piece of the extra wire you have from the Crack kit and cut it to 1".  Strip each end 1/4".  Attach and solder one end to A3.  Attach and solder the other end to A8.

 

[Jackie.tang]

That did the trick.

Thanks a lot, Paul!