Audio Systems: defective car speaker, 1990 cadillac seville, cadillac seville

Question
thanks for the quick reply...however ,, I HAVE NO NEED TO TEST RADIO / AMP OR WIRING TO SPEAKER,, BECAUSE I KNOW THE SPEAKER IS DEFECTIVE. WITHOUT A DIAGRAM OR SCHEMATIC HOWEVER , I WOULD STILL LIKE TO UNDERSTAND THE CIRCIRCUITRY BENEITH THE CONE INORDER TO DETERMIN WHERE THE "OPEN" MAY BE OCCURING. CAN IT BE DISASSEMBLED WITHOUT DAMAGE ?
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-----Question-----
have replaced a defective car speaker ; but want to understand why it doesn't function. car is a 1990 cadillac seville. speaker is a typical 6x9 , 25 watt , 10 OHM unit. resistance spec across leads is 4 - 15 OHMS. resistance check reflects "O". as leads are in tack to cone, what component is open / failed resulting in no resistance & non - function? can such a failure be repaired & how ?
-----Answer-----
"0" ohms is a dead short.  That is very bad news.

Speaker resistance should be a very stable reading at a little less than the rated impedance.  Rated impedance is for when the speaker is driven with audio signals. It varies over quite a wide range depending on frequency.

Check the speaker with a 1.5v D cell or 9v battery by placing the battery directly to the terminals of the speaker. If you don't get a loud click when the battery touches the terminals then it is defective.

You must find out where the problem is before the repair can be decided.  I suggest you check the wiring between the back of the radio/amp and the speaker for shorts or opens.

Also, you can substitute one speaker for a known good one to test also.

Let me know if you need more.
C


Answer
My advice remains the same.  You must determine what the defect is.  But, zero ohms is a short, not an open.  If the speaker is measuring zero or near zero ohms as you stated in your original message it is short.  So, you must carefully examine the wires as they go into the spider area and examine for shorts.  I suspect the voice coil is shorted down.  A common failure.

There are shops that will repair voice coils for a fee.  Sometimes you can repair them by yourself, but it takes a basket of exacto knives, special adhesives and the know how to repair and reattach the voice coil wires. If the short in down deep in the voice coil you will not be able to repair it unless you have a replacement coil, know how to replace eit and center it as it is reassembled.  It is a specialty that not many people know how to do.

My advice:  Just go out and buy a new speaker!
Good Luck,
c