Refractor Build Problem

[vaughnfats]

I've just finished a Refractor build (not my first) and have an issue for the first time.

No power with a fresh battery (well almost fresh at 8.86 volts)
Powers up with a power supply
No signal pass
When I increase the treble control I get a wonderful rising theremin like oscillator.

My first check will be verifying the harness from the switch board to the I/O board. Maybe I reversed the pins?

This is the first build of any kind that I've had to troubleshoot and though I'd check in to see if anyone has any sage advice before I get the meter out.

TIA

Fats

[EBK]

With this specific project, my first question for anyone having problems is:
Are you absolutely sure that the tantalum cap on the board is oriented the right way?

[vaughnfats]

That is on my list of potential problems. I checked all the electrolytics visually against the print but haven't put the probes on the tantalum. Do you think that could cause the behavior I've indicated?

[EBK]

... but haven't put the probes on the tantalum.

Check it visually, just like with the electrolytic caps.  There should be a small plus sign marking the positive lead.

As far as whether it explains any of your problems, I don't know.  I've seen the issue cause strange things to happen before, so it is worth a check, especially since it should take only a few seconds to inspect.

Almost forgot the most important thing:
Welcome to the forum!

[bluebunny]

If you get no power from your battery, but power from a wart is OK, then I'd look at your wiring.  Can you do us some photos?

And welcome, of course!