AR speaker droppout

[dynaco_dan]

Hi there;

Beginning of rattle.

When I was working at the local AR warantee depot, I came across a puzzling situation with an AR-4X speaker.

This speaker had been serviced in our shop recently and was shipped back to us with the same problem as before, no tweeter output.

It was the first I saw any repaired item returned and so quickly to.

Remember that AR was paying for the round trip shipping again.

I put it on my test bench, ran the usual audio tests and there was no tweeter output.

Turning the pot did not help even.

Cut out the grill cloth and pulled the tweeter and the wires were soldered real good.

I automatically tried another tweeter and still there was no output.

I rechecked the speaker cable input and everything was fine.

I then pulled out the woofer and checked out the crossover thinking there must be a broken wire, initially.

Looking at the crossover, I saw that all the solder connections were nice and shiney.

There was one little thing that did catch my eye, that was the point of contact of each end of a bare, there was a tin plated copper wire that was a jumper on the crossover.

I thought I would just touch up the solder a little.

Soldering of copper pipes and electronic kits, has given me an eye for the proper appearance of the finish.

I touched up, or tried to touch up one end, but I had to add flux to the Rosin core solder and still I wasn't having any success.

Last but not least, I thought I'll just remove the jumper, re-solder another piece of insulated wire and that's how she wrote.

What I was amazed to find, and this can and did happen, even as rare as this might sound, a piece of spring steel was used in error.

Normally spring steel is not solderable.

It looked tinned, but I will guess that AR as well as others probably bought these jumpers wires pre-cut by another supplier, and this booboo just happened to end up as an AR-4X jumper.

It was not actually soldered into place at the factory, but was passed, and was used by the customer, until finally one day there was the tweeter dropout.

I think I would have better odds of winning a lottery, than to see something like that, twice in a lifetime.

End of rattle.