Those really don't look like they should be connected together.

Yeah...my bad lol. :S Took that wire out...
 
The part highlighted in red looks damaged on the PCB though. (Still getting low ohms between the two contacts by the way)
 

If you had actually tried to connect the battery in reverse polarity (which is what would have happened if the contacts were installed wrong and you plug in a battery), then the D4 zener diode would almost certainly have fried.  Often this causes the diode's internal junction to become shorted.

I see...well then that's probably what happened. I guess ordering another D4 diode may fix it...but I'm not sure about the part in red I highlighted earlier. I may just start over on another PCB and install the contacts the right way :S...I'm not sure though.

You could pull the D4 diode and see if you are still getting the low ohms reading

Quote:

pars said:

You could pull the D4 diode and see if you are still getting the low ohms reading

Click to expand...

I'll have to try that...
 
It looks like the center B- contact is damaged though--do I need to fix that?

Yes, you do.  If you follow the PCB layout you'll see that the center pin of the battery contacts is the one that does the "real work".

Quote:

amb said:

Yes, you do.  If you follow the PCB layout you'll see that the center pin of the battery contacts is the one that does the "real work".

Click to expand...

Okay...so it looks like it connects to the ground plane on the board. Could I just run a wire from the B- contact to say another ground like the DC plug ground? Or is that completely wrong... (still learning )

Quote:

Okay...so it looks like it connects to the ground plane on the board. Could I just run a wire from the B- contact to say another ground like the DC plug ground? Or is that completely wrong... (still learning

)

Click to expand...

See the schematic diagram and you'll be able to answer your own question.  Btw, that's not the "ground" plane.  It's the "C-" plane and is on the top side of the board in the power supply area only.  The ground plane (IG) is on the bottom of the board.  The two are not to be confused.

So can I connect the B- to something else on the C- plane like the anode of the D4 diode? 

Yes, isn't that what the schematic tells you?

Yes, I was just confirming to make sure I didn't make a mistake. Thanks

Hi everyone, first time post but I've been reading the DIY forum with much enjoyment for a while. I did the same thing with the Mini 3 I finished building two days ago. It was the only connection I didn't double check before soldering - Live and Learn!!!
 
Fortunately I didn't fry the diode and when I put the battery in the 'wrong' way. Something went click while I was working through the checks and I thought I would've cooked something. I just connected a 9v cable connection underneath to see if it would work, and it did. The sound is awesome.
 
I think I'm going to take the other option and drill out the battery connections at the top and not touch the soldering, then either rivet or solder them back in the correct orientation.
 
Ti - thanks so much for a project like the Mini 3 - it was my first soldering since installing a car stereo many years ago. With the references on your website, Tangent's soldering video's and the builders guide on this forum a complete beginner was able to make it - Thank you.
 
Cheers

Drilling a circuit board that has plated through holes is a very bad idea.

I think dontdiewondering was talking about drilling the battery contacts themselves, which would probably destroy them anyway.