Any easy way for newbie to trigger 12V on subwoofer without receiver?

[Hogwild]

Polarity of the switch-on voltage?

Assume I know nothing. Would you please explain?

[Phil1977]

Just the orientation of the 9V-block. Which pole you connected with which contact on the woofer?

[Hogwild]

9v-block? I have no idea what that is.

Pole? I don't understand how poles apply here or what you mean.

[Phil1977]

Sorry for my English, in Germany we usually call 9V-batteries "9V-blocks". And with "pole" I meant terminal.

Both are "false friends" - for me it reads like correct terminology, but it seems it isn't 

[Hogwild]

Oh. Thanks for that. Yes, double-checked that I was using proper polarity. And I heard a relay click each time I applied the power to that jack.

[Hogwild]

My 9V battery reads about 8V on a DMM. But I assume if I heard a click, then the relay was opened? It's either fully on or fully off, right?

[Phil1977]

Mostly yes but not necessarily.

Do you have a power meter? Can you check the power consumption of the subwoofer?

I´m quite sure it´s not active. Even if the input sensitivity is quite low, you definitely shoud hear a low signal if you connect any low level source.

[Hogwild]

Well, considering Nakamichi's documentation basically says it's active...

I have a Kill-A-Watt. Would that do the job?

[Phil1977]

What kind of documentation do you have?

Yes, a killawatt should show you a different power reading when the relais is on or off. If it´s the same the relais is probably not switching or some fuse is blown.

[Hogwild]

I'll try it. I have the schematic for all the modules but the amp/subwoofer. For some reason, I can't find those on the Web, except for a couple people who are selling them for between $USD 30.00 and 50.00. I'm not willing to pay that in this particular case.

[Hogwild]

I only connected it for a few seconds, but no change on the Kill-A-Watt. Measured 0.

[Phil1977]

Then you have to open it and look for blown fuses and caps...

[Hogwild]

I'll take a look at it.

[Hogwild]

I opened it up, but I can't seem to find a fuse at all, and no bad caps that I can see. Maybe I'm missing it.
Attached, are a few photos.

[Hogwild]

Here's a couple more photos. I took all these photos before thinking that I really should've been focussing on the caps. I'll take another look at all the caps and photograph anything that looks suspect.

[Hogwild]

I just briefly checked continuity from the AC inlet to the inputs on the Power supply. The meter beeped, but sometimes it took a bit of moving the probes around. And the solder joints are pretty cold-looking. Is it worth it for me to try to reflow the solder on those joints, or is continuity usually a bit fussy to test for on solder joints?