Here is a thread for boring electrical questions!

the lighter trick might work great though.

I have contacted the seller (an eBay one) about a replacement but in the meantime, is it bad for the decoder box to even be using it? Also, isn't UK mains supply 230V, not 240V? Does this matter?

What is this connection called and where can I get power supply for it (this is a rechargeable 12v block battery):

http://i58.tinypic.com/etuyza.jpg

Connector variously known as blade connectors, lug connectors, quick disconnects. Should be available at hardware stores, Home Depot etc. stocked near the wire nuts, as well as at car stereo shops, maybe Radio Shack. They're available in many sizes so it needs to match. Looks something like this:
http://ecx.images-amazon.com/images/I/213xMczDrhL._AA160_.jpg
Power supply to keep the battery charged I think will need a transformer to convert AC/mains home electricity which is 115v or 230v to the battery voltage which is probably in the 5v to 24v range; this is usually built into the device the battery is in (a UPS?). If you're in the US call a Batteries Plus store.

Thanks!

I got an AC adapter that seems to connect to the above except that the red and black are switched around. Is there any way to separate and switch the red connectors in the picture above? I can't quite tell how they are held together...

switch the red and black connectors

rough guess is that the adapter is the opposite polarity? if you feel adventurous I would just swap those two wires in the pic upthread (i.e cut them about two inches below the connectors, strip the ends back, switch red & black, & splice them in w/wire nuts) so it is reversed.

what is the battery used for? that might help determine the voltage it likes to charge with, you don't want it too high.

Battery is used for powering a 16mm film camera.

I wish I could do what you are saying but I am totally an idiot electrician and don't want to screw up my battery/kill myself. Maybe I can find a smarter one to help out somewhere.

I just talked to our electrical engineer at work

those are Anderson connectors, Allied Electronics makes them - there are two different sizes.

wish I could help more

what voltage DC does your AC adapter put out?

do you own a voltmeter?

Thanks a lot!

AC Adapter is 15V by the looks of it. It connects perfectly to the battery but only red-to-black and black-to-red, which I'm sure isn't good.

Really appreciate this. I would love to get this working but it's at the limits of my knowledge/expertise.

yeah I imagine finding a battery for a 16 mm isn't easy

my roommate uses a lot of projectors and old film for light shows, I will pick his brain this evening.

15V is perfect, so that's good - just make sure the output is DC not AC.

would you consider swapping the leads on the adapter, leaving the battery as is? is there a little diagram on the adapter that shows polarity? it woudl be a little almost-circle with a dot in the middle, and a + or - sign pointing to the center dot.

Actually, it's for a motor that attaches to 16mm Bolex.

output is DC, yes

Looking at adapter now, there is a diagram with + and -, but no indication of center. I'll post when I get a chance.

Naive question, but is "switching" them just separating the red and black and reconnecting them in the opposite configuration? Or does it involve soldering, etc.?

OK here is adapter:
http://i58.tinypic.com/qzmz4j.jpg

and incompatible connectors (they fit together this way, battery is bottom and adapter is top):
http://i57.tinypic.com/2lk3dow.jpg

oops sorry I should have formatted that adapter pic. Hopefully you can read sideways...

I will get back to this later, I promise

would you consider swapping the leads on the adapter, leaving the battery as is? is there a little diagram on the adapter that shows polarity? it woudl be a little almost-circle with a dot in the middle, and a + or - sign pointing to the center dot.

Looking at adapter now, there is a diagram with + and -, but no indication of center.

Polarity diagrams with the dot in the center are used only for round connectors to indicate inner and outer. The polarity diagram on this battery shows the side by side connectors as viewed looking into the connector with the wires behind it. The standard arrangement is plus = red, minus = black.

What's holding the red and black connectors together? (a screw, a rivet, glue, just slid on from back to front?) Swapping them should work if you can figure out how to separate either side.

Looks like they kind of slot together, but I'm guessing there's glue too?

yeah I think you can slide the Anderson types apart

listen to Lee, he knows more than I do

Ah! I separated them! oops, that was easy...now...sage to plug this in? I'm not gonna die, right?

SAFE to plug

try holding one side and either pulling or pushing the other to slide it out; should separate if they're not glued. Or you could just take a knife to it.

setup:

1x receiver
2x powered speakers
cable box
roku
blu-ray player (lol what for I don't know)
TV

This is all plugged in through the same "smart strip" surge protector. everything is at most 7 years old. Yesterday, one of the powered speakers started contributing a nice steady ground loop hum, so I replaced the speaker cable to both, switch speaker sides (so if it were the power cables, I'd know) and no joy. So that speaker's off now. This morning the cable box has started complaining of issues, and because it's an xfinity POS it just craps out and tells you to cycle the power. No cable issues otherwise.

This couldn't be because the surge protector's going to shit or something, right? The cable box and the speaker hum are just shitty old coincidence, yes?

have you tried a ground lift for the speaker hum?