Polaris OBark

Thankfully the switching power supply was unplugged from the mains, but our dog chewed the bi-wire that goes between the power supply and the trainer. The wire is molded into the power supply, so replacing just the cable might not be an option. Since he chewed up the middle of the wire, I could potentially splice it. However, I can't distinguish polarity on the wire ends. Does that even matter? I would hate to fry the trainer circuitry because I am too cheap and lazy to buy a $30 replacement power supply (with cable attached).

unterhausen

I'm sure polarity matters on the trainer side. Many a kickr has been smoked due to getting the right voltage power supply with the wrong polarity. I expect other trainers are the same.

Are you sure the wires aren't different colors? You should be able to sort them out if there are hieroglyphs on the power brick.

BTinNYC 

What ^ he said.

Polaris OBark

I had a closer look. If you look closely at the wire in the lower left next to the EMI clamp filter, you can see on one side it has a long white marking punctuated with short wire-casing colored markings. So I guess all I have to do is match them up. Hopefully.

ScottCommutes

Don't let your pooch electrocute himself chewing stuff!

zacster

It's a 48v power supply so don't make a mistake with it. But you know what, they cost $30 from Saris, just buy another one.

Chuck M 

Since you have identified the white tracer, you should be good to splice the cord back together. I would recommend soldering the joints and shrink wrapping them. If you don't have the tools for that, I'd just spring for the replacement .

Polaris OBark

I do have the tools. Thankfully the power supply was unplugged from the mains. He just found the wire on the floor where it shouldn't have been. He is 13 now, and doesn't usually chew stuff. My wife might have done it with the vacuum cleaner, although usually there is a pretty strong alibi (nobody does much housework around here).

Polaris OBark

This will have to wait for a trip to the hardware store (as tempting as it is to just twist copper strands together and wrap in electrical tape). I used up all my wire splicing stuff a few weeks ago when rats ate the temperature probe wires in our hot tub.

California, Uber alles.

zacster

If you have a voltmeter check the polarity at the plug when you are done to ensure you didn't make a mistake. If you don't have one, get one. They're pretty cheap these days. When I was working on vacuum tube gear with high voltages it was recommended to get multiple cheap VMs so that you could set up all your readings with alligator clips at once and not have to be sticking a probe into high-voltages. While I never had anything happen I started following that advice. Take B+, cathode and heater voltage all at once. Make sure that tube is getting what you expect.

Polaris OBark

I have a volt-meter, but there was no need, and I am not sure what the correct answer would be, because it has one of those female coaxial plugs at the end of the wire. By convention, neg would be outside, but do they adhere to convention? I just matched the wires, stripped the ends, and re-connected them. I found some heat shrink tubing and spliced the two marked wires together, the two unmarked wires together, and sealed up the whole thing. It looks ugly but it should hold. I tested it and it works as it should.

Now I have to decide if I want to be a responsible adult and order a whole new power supply.

unterhausen

There should be a label on the power supply box to show polarity. It must be a regulatory requirement, it's on every one I have seen. I'll admit that I often have to stare at it for a while to understand what they are trying to convey.

choddo

Nah. Waste of earth’s finite resources.

Polaris OBark

Between the mains and the power supply, yes, and in addition, the cord is notched so the user cannot invert it. (Having a grounding pin would also enforce polarity, but for some reason vendors and customers seem to prefer ungrounded electrical appliances.)

The issue with this was rejoining the severed wire without inadvertently changing the polarity. Even if the case was labeled, there would still be an ambiguity, unless the wire itself had a marking. Fortunately, it did, but I didn't see it until you suggested I look again (thank you!).

More worrysome is that I think something is going on with the dog...