Diagnosing a faulty tonearm cable

[bulgin]

Hi

I recently built a new tonearm cable for a Micro MR-711. All my turntables are using the same high grade arm cables with silver over copper inside. The source or brand of these cables are unknown but a clue is a fitting at the phono plug end bearing the Micro legend. I don't know any longer where and when I acquired these pieces of cable but I like using them a lot because of the generous amount of copper in them,

Anyway, the job of building the new cable with a 5-pin din connector at one end and a pair of phono plugs and earth tag at the other was uneventful and everything worked correctly when the job was done. Btw, the cable doesn't plug directly into the Micro's arm, it goes into a 5-pin chassis mount din socket.

I used the cable for a few weeks and yesterday, I noticed a loss of the left channel and lots of hum.

I opened all connectors and re-checked and re-soldered all joints, suspecting a dry joint but picked up no problem except for the dead left channel.

I later cut off all connectors at both ends and started snipping off pieces of wire at both ends, checking for continuity but still no luck in finding the break which is left +.

This is my last piece of superlative armcable and cutting off pieces at each end, has brought me close to 'borderline' for a decent length of armcable. I have since built a new armcable from some different cable I had here, but would still like to use the cable I used originally.

The break is somewhere inside the cable but where? I've got no X-ray vision and sticking pins through the outer sheathes isn't an option in tracking the break.

Is there an instrument which can determine such internal breaks in cable or shall I continue snipping off pieces?

bulgin

[bulgin]

03:35 and happy to report I saved the remains of the cable. I had to snip off about 3cm bit by bit and stuck a pin into each end of the left channel's +, until I had continuity end to end.

The pins were necessary to make it easier to test with the Fluke probes.

bulgin

[Big_Bill]

Originally Posted by bulgin

03:35 and happy to report I saved the remains of the cable. I had to snip off about 3cm bit by bit and stuck a pin into each end of the left channel's +, until I had continuity end to end.

The pins were necessary to make it easier to test with the Fluke probes.

bulgin

Were you able determine the cause of the break in continuity?

[bulgin]

Hi

I'm not sure what caused the break. The cable stock I used is very old but I'm not sure if copper gets brittle with age.

The likely spot where the break occurred was just past the din connector. The turntable was perhaps too close to the wall , causing the + wires from one channel to break inside.

bulgin