[sdiy] PAIA Tubehead not functioning

[Travis Shire]

> Hi Robert,
>
> If you're not getting power to the LED it's likely that the problem is
> in the power supply. I'm not particularly familiar with this project
> but this is a good opportunity to hone your diagnosis skills. Use a
> voltmeter to check for correct voltages at the LED and trace back to
> the secondary of the transformer. Be careful and use the correct
> settings AC vs DC and the correct voltage range of the meter. Be extra
> careful testing on the primary side of the transformer. This type of
> diagnosis is common when things don't work the first time. The voltage
> stops somewhere and it's probably before the LED.
>
> I'll let others with  more specific knowledge chime in with more details.
>
>
Schematic:
http://www.christianmusicweb.com/schematics/paia_tube_head.jpg

First off, make sure the wall wart you use is 12VAC, not DC. Verfy
orientation of the diodes in the +/-12v supply. Once you have the V rails,
the hex inverter voltage step up section should take off.