Harmon Kardon SC7

[bstevenson01]

I acquired a Harmon Kardon SC7 Componant system, with the Dual 1009 table in it. When I found it, I looked under a loupe at the needle, and saw that it was pretty dull. I tested a couple scrap records and noticed a lot of crackling noise and distortion. I replaced the cartidge with an Audio Technica unversal, and it improved the sound a lot.

 

The problem i'm having is that when my arm swings from its neutral position to playing position, I still get a really loud crackling distorted noise, as if I were having trouble plugging a cable into a guitar with a half-stack turned to 10.

 

It almost seems as if there is a bad connection that is being interrupted whenever the arm moves, but I know very little about the inner-workings of it, and I am hesitant to begin operating on it.

 

Any suggestions?

[allenh]

a bad earth or bad or dirty connections in the arm wiring seem the most likely. or the arm wiring insulation may have broken down so it is shorting on the arm tube.

 

You can check this if you have a multimeter and know how to use it.

[bstevenson01]

a bad earth or bad or dirty connections in the arm wiring seem the most likely. or the arm wiring insulation may have broken down so it is shorting on the arm tube.

 

You can check this if you have a multimeter and know how to use it.

 

If I test it and find that its the case, what kind of work am I looking at to fix it? Just replacing the wiring, or the arm itself?

[bstevenson01]

Thank you for the point in the right direction though!

[allenh]

It depends where the problem is, if its at either end then provided there is enough spare wire it's just a re-terminate provided you are comfortable with soldering and wire terminating, if it's inside as in the insulation breaking down or the internal earth connection then it's a bit more daunting, arms are pretty easy to rewire as you just use the old to pull in the new but it can be quite fiddly.

 

A dirty earth connection is most likely and is possibly no more than the arm earth connection breaking so earth is trying to make a path through the bearings which is inconsistent and where the noise is coming from. usually there is a 5th wire in the arm wiring which fixes to the arm tube or bearing body somewhere and this is usually the connection that breaks, again this is quite easy to test with a multimeter.

 

Upgrading the wire inside an arm is generally a very cheap but fiddly upgrade, it just depends how practical and competent you are, so if you do end up needing to do it just keep in mind that if you norse it up you will need a new arm or complete turntable if the arm is not replaceable.

[allenh]

one point though, with the 1009 being an idler wheel deck it will be worth saving if it's time and minimal money that you need to invest, they don't have a great value but can produce some very nice sounds when working properly.

[gabpower]

Sounds like a wiring problem by your tonearm or the wires connections/solders.

 

If I had that problem, I would check that by myself since I work in electronics but if you're not that handy with assembling and dessembling common devices your may do it wrong and cause more arm. 

 

My best advice is to ask a turntable professional to check it and repair it but that would cost you.