Speaker Repair

[Freeman]

Hi all. I think I have a failed crossover in one of my Quad Lite II's in my AV setup (no low frequency) so I'm looking for someone who can repair in the Reading/Guildford area? Does anyone have any recommendations? Failing that I may upgrade

[Pharos]

Immediate response, check the bass driver with a meter or battery, this being IMO the most likely failure.

[Freeman]

Thanks Pharos. Do you mean check continuity across the bass driver terminals?

[Pharos]

Yes, probably about 3 ohms.

[Puffin]

Before seeking professional help I would do some investigating. Get access to the innards and see if anything has come adrift. Some drive units are coupled to the crossover with wires that have push-on spade terminals, one of these may have failed. The terminal plate could have a loose connection behind the binding post?

If testing a drive unit with a battery, use a 1.5v and solder a wire to - and + and test the bass unit by momentarily touching + by holding - to either the binding posts or if you have made access inside touch the speaker drive unit terminals. The unit should move outwards with - & + battery connections correctly corresponding to the binding posts/drive unit markings.

If there is no cone movement when testing at the binding posts, then it could be a failed crossover component. If testing the bass driver at the terminals and there is no movement then it could be dead.

Do have any equipment to test the crossover components?

I am in Haslemere, Surrey if that is any good to you.

[sailor]

Yes, do as Rob above suggested, also try gently pressing on the cone which may have frozen in place and if it moves freely then it may be the voice coil has failed or the signal just does not reach the speaker in which case it's time for the battery.

Connecting the battery directly across the speaker terminals should produce a clearly audible 'click'. If the cone moves try the battery across the crossover input points where the amplifier connects to the XO board and if no click then the problem lies somewhere in-between.

Connect the -Ve from battery to XO common -Ve and use the battery +Ve lead as a probe to find where the problem is. If it is the inductor (unlikely but who knows?) you can temporarily bypass it with a scrap of wire to get sound again. It will not sound quite the same but no harm done.

[Freeman]

Update, have swapped out the offending drive unit with one from another speaker. The problem has now transfered so that discounts the crossover. There is however some output which doesn't sound good, especially with a test tone. I've inspected the drive unit and cannot see any dry/broken solder joints. I think I'm at the stage now where I search for a donor on ebay or look at an upgrade!

Thanks everyone for your replies and offers of help.

[Puffin]

Update, have swapped out the offending drive unit with one from another speaker. The problem has now transfered so that discounts the crossover.

[Barry]

I think Mark means he has swapped over the drive units (bass?) of the speaker pair.

[Freeman]

Yes, the problem followed the mid/bass driver as I swapped it out into another speaker.

I looks like I have sourced a donor speaker now so normal service should be resumed shortly.