Replacing midrange on OA116

[ColesKing]

I need to replace the midrange units on two OA116 boxes that I recently bought - I assume it is the speaker cone itself which is defective. Maybe there is something else that I need to look at. The deep bass units seem to be OK and are playing well although I have not physically examined them.

I need some help on this. I have found the exact type at Hifikit.se (the 16 Ohm type). Is it just simply a case of unscrewing the cones and "gently pulling out" the attached wires, unsoldering/resoldering and fitting? Or are there some other things that I need to know about - it says on this site that the OA116's are difficult to restore - what does it mean here by difficult.

I want to get as much information and help before I actually start to do this, for obvious reasons.

I would appreciate any general help, no matter how simple it might appear to the person giving the help - Sonab Loudspeakers are valuable and I want to make sure that I do not damage anything in the process.

Thanks

ColesKing

[phon]

The midrange speakers are easy to replace. It's done as you suggested, unscrew and lift up the old one, plug the wires into the new one and screw it back on place. No soldering needed. The HiFiKit 16 ohm unit is the correct one to replace with.

For the bass unit, you might want to check the foam surrounds, they are the most likely to fail on old speaker units. HiFiKit stores new bass units as well. If you find it difficult to disassamble the speaker you will no doubt hear when/if the bass units fails.

[ColesKing]

I took out the midrange today and just checked it via a little 1.5 Volt Penlight Battery - there is a response from the driver so it is not this unit which is at fault.

Does anyone have some specific advice on how to "dig deeper" to find out why this driver is not playing?

I obviously want to tread carefully and can benefit from previous experience gained by others.

ColesKing

[ColesKing]

Somebody must have had similar issues before like this.

[phon]

OK, the driver works, so has to be the cabling then. The midrange (and tweeters) are fed from the bottom side of the cabinet, there are 4 wires run along the bass tube. The bass and midrange filters ar placed on the bass baffle, the tweeter filter sits under the top baffle.

All cables have push-on terminals, maybe one of them is loose? Do you have the wiring diagram for the speaker? The midrange cables are orange and brown.

[ColesKing]

Thanks for the advice.

As far as I understand - to get to the wiring/circuitry for the midrange, it would be a case of removing the base and then the circuitry is attached to this part. Is this correct?

It says here in Carlssonplanet that the OA116 is "difficult to restore" and for this reason, I am a liitle wary of opening up the base and finding that I hurt something in the process.

I have no wiring diagram,but have seen that these two wires are orange and brown, as you say.

I would welcome any help or guidance from someone here on this issue.

ColesKIng

[lemmts]

Just a thought: are the jumpers all right? If they are you have to open the speaker.

I think I remember (it was two yeras ago) that the cables running from the midrange elements are cut and joined by push-on terminals under the top baffle and not running all the way down to the filter on the bottom baffle.

The top baffle is divided into two parts, one for the midrange and one for the six tweeters. You have to unscrew the eight screws holding the tweeter baffle, and lift it upwards. You can use the "knob" as handle. It might be stuck, the rubber boxseal acting as glue. But after a little "wiggling" it will come loose. Now you can check the wiring.

It isn't more complicated than this to restore the speakers, but you have to be very carefull. You unscrew a lot of screws and dismount the speaker piece by piece. Write down what you are doing, so you can put the pieces together again. It will take some time to do it, and you need a large workingarea.

Start with the two top baffles. The most difficult thing is to loose the bottom baffle. It can by very hard to get it off. It is only fastened with the 12 (16?) screws, but the old boxseal acts as glue. Be careful.

Good luck!

Lasse

[phon]

This is the base baffle, the midrange (and highrange) cables runs along the tube and are fixed with plastic tape to the top. The baffle itself is possible to pull loose from the speaker. It sits with 12 screws to the cabinet.

Easiest is to have the speaker laying flat on side on the floor. Place a soft clothe to protect both speaker and the floor. Baffle might stick to the rubber sealing. You will be able to pull baffle out 3-4 inches before disconnecting the 4 wires to the top.

With baffle separated from speaker it is possible to inspect the midrange filter and cable connectors. It is also possible to measure the midrange seen from the far end of the cables. Please mind to take notes on wire colours and positions before disconnecting.