Troubleshooting cables

D

devilmanterry

Audioholic Intern
The basement of my house had coax cables installed for 2 subs prior to me moving in. I recently bought 2 subs and I'm having trouble getting them to play. When i initially went to plug the pre-wired sub cables in to my receiver, the RCA plugs pulled right off the cable on both connections. So I bought new RCA crimp plugs and a crimp tool and crimped 2 new RCA plugs on (admittedly I didn't do an awesome job, but believe I got them crimped on well enough - so this could be a source of the issue). I also bought 2 coax to RCA converters that I connected at the wall outlets and then ran traditional sub cables to both the subs. Neither works though - one hums, the other has no sound at all. I haven't had a chance to actually test the coax cables, as I understand it I need specific equipment for that? I was wondering if anything I've done would jump out as a potential problem? How finnicky are the RCA connections? Would the coax to rca converter at the wall impact this?

I have connected both subs directly to the receiver and they work fine, so I can eliminate the sub cables, sub and receiver themselves. Thanks in advance for any advice.
 
Mark E. Long

Mark E. Long

Audioholic General
Get a cheap multi meter and check the cables or run new wire something is amiss there myself if its possible id just run from the receiver to the subs and be done . but I do understand the desire for running them hidden in the wall tho good luck Sir .
 
Speedskater

Speedskater

Audioholic General
by "coax to RCA converter" do you mean 'F' connector to RCA connector adapter?
anyway: with your new multi-meter (DMM) in the Ohm position. disconnect both ends of both cables. Reading from center pin to shell should show 'open'. at the far end of one cable, somehow short the center pin to the shell, at the near end the meter should read just a few Ohms. repeat for the other cable.
 
D

devilmanterry

Audioholic Intern
by "coax to RCA converter" do you mean 'F' connector to RCA connector adapter?
anyway: with your new multi-meter (DMM) in the Ohm position. disconnect both ends of both cables. Reading from center pin to shell should show 'open'. at the far end of one cable, somehow short the center pin to the shell, at the near end the meter should read just a few Ohms. repeat for the other cable.
Yes it's an F connector to RCA adapter. I'll get my hands on a multi-meter and test. To short the center pin to the shell, you just mean to touch the two surfaces?
 
Speedskater

Speedskater

Audioholic General
Yep, touch them together. use a paper-clip or a piece of wire
 
Speedskater

Speedskater

Audioholic General
No, don't undo the connectors. At least at first. If the meter still reads 'open' then investigate further.
 
highfigh

highfigh

Seriously, I have no life.
No, don't undo the connectors. At least at first. If the meter still reads 'open' then investigate further.
Do you have barrel connector for connecting two coax cables? Use that. If you don't have one, do you have any test leads? You can also bend the center wire and make it contact the ferrule. After the center has been shorted to the ferrule, measure between the center and ferrule at the other end- you should see almost zero Ohms. If you think the ends were attached badly, remove them and strip the ends before repeating the test- badly attached ends cause a lot of problems.

If it hums, wiggle the cable at the input to the sub- if it changes, repair the end. If not, repeat at the source end and act accordingly.
 
D

devilmanterry

Audioholic Intern
@Speekskater - ok, so just touch a wire to the center of the RCA plug and the outer metal portion that surrounds it and goes around the female RCA plug?

@highfive - I do have a few barrel connectors for the coax (that's what the prev. owner put in wall plates when they left). I did replace them with the Keyston F Female to RCA Female inserts (could that be the problem?), but easy to switch back. When you say use that, what do you mean use it for? Are you saying connect another coax cable to those that were wired in the walls, or use that barrel connector for testing purposes?

I have a spare piece of coax cable that's stripped at one end that I could use to test connections.
 
D

devilmanterry

Audioholic Intern
I finally got my hands on a DMM and followed the advice here, and the meter was all over the place. I also used the barrel connector to connect a spare coax to the wall outlets and tested the connectivity from the wall to the receiver connections and got nothing. I assume the next step is to remove the RCA crimp connectors and test the cable itself?
 
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