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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I have recently acquired a pair of S45.2 speakers from retro junkie of ebay fame, one of which was described as having a woofer driver seized, not taken them apart as yet due to the volume of mundane tasks dictated by the woman in my life, however I suspect a misaligned magnet as this seems to be the most prevalent thread posted in these rooms. When I get permission to revert to my own activities once more I will chronicle the excercise along with some pictures.
Finally got round to having a look, first one has a couple of heavy scratches on one side, the cloth looks worse for ware in one corner.
This will require both speakers being recovered....
the bass driver is frozen solid, the rubber mounts look in good shape however
finally getting back to the proper jobs in my life, removed the driver from the cabinet
however I'm at a bit of a loss as to the best way to get into it
I think the grill type cover needs to be removed, the cobalt magnet looks like it could easily be damaged however
So.....any advice from those who have been here before would be welcome
Great speaker's I am yet to hear better waiting on some s75's
good luck with your project
found this http://archivedforum2.beoworld.org/forums/thread/191211.aspx
Irata has documented the procedure very well in this blow by blow thread......
Dear Craig,
S45-2 speakers are very good playing speakers and definitely worth to restore them.
Wood work could be done with great success, you will find here veneer repair here in forum. Take some drops of hot water to the wood scratch (only) or use steam from boiling water, hot water will help to recover wood. After some hours clean veneer with isopropyl alcohol and take sand paper ...
I was trying to repair dislocated magnet using above mentioned thread and no luck, I was not able to center the coil inside magnet.
So another solution for me was to ask Dillen (Beoworld respected member), he helped me to source woofer easily.
Priklep
Thank you for your encouragement, I will certainly give these speakers my best shot. Gripped the errant driver in a vice this evening and was shocked by how easily the magnet detached from the housing, it was almost like the only thing holding it in place was the paint.
The pole piece is still securely fixed and looks central in the magnet, as I see no reason to disturb it I'm going to clean it up in situ.
The dremel with a wire wheel lends itself to this task quite well
the magnet and pole piece now look acceptable, and feel very solid.
However...that's the good news over, the bad news is that the coil is binding very badly within the housing....it needs to come out and be re aligned
The girlfriends hairdryer has been dragooned into service for this next exercise to good effect, the glue loosened eventually and I was able to remove the dustcap.
next the cone was removed from the frame, the rubber seal came off with the hairdryer, the diaphragm needed to be put to the knife however.
at this point I did try and align the magnet/pole and frame, bear in mind that at this point the pole piece magnet and backplate where still all in one piece.....this proved to be very difficult, every time the magnet assembly was offered up to the frame the pole piece immediately stuck itself to one side of the frame opening and fitting shims, even if fitted before mating up, was proving a nightmare. This wasn't working for me...so I pulled the backplate off the magnet and freed the pole piece, now all three are seperate
I am thinking that if I separate the magnet and back plate, glue the magnet to the speaker frame and then re attach the pole to the back plate and epoxy it in place, it will be easier to centre the pole piece in the frame prior to epoxy glueing the back plate itself to the magnet.......this looks like the way irata achieved the centralisation exercise......so I have applied the epoxy, roughly centered the magnet to the frame and similarly roughly centered the pole piece on the back plate and I'm now waiting for the epoxy to set........
I don't think these parts need to be dead centre at this point, the important aligning is when the back plate and pole piece are attached to the magnet, there should be lots of adjustment available to me when I do this.....for now a glass of wine is the way forward as I wait.
now that everything has dried out, including me, its time to fit the shims. I used bits of card, placed an o ring around the pole piece to hold them equidistant before selotaping them together....I found it a bit fiddly without this aid.
As irata advised I set the base plate in the vice a couple of mm below the level of the vice jaws, so what happens when you place the frame and magnet onto the pole and base is that the magnet is immediately attracted to the base plate but the vice jaws stop contact, the surface are of the jaws are less than that of the face of the baseplate so you can shuffle the whole thing slightly when aligning the shims (was a very good tip this). naturally the shims where slightly too thin so I fitted more as can be seen
when satisfied with the alignment and shim position I released the vice jaws gingerly....the magnet snapped onto the base plate, the shims held everything central, so I applied liberal amounts of epoxy all around the perimeter of the base plate, I didn't put any on the face of the base plate in case I couldn't get everything lined up, epoxy everywhere would have been a pain to deal with had that been the case.
after a couple of hours I pulled out the shims to see what it looked like, I'm optimistic that this is going to work out, the pole look central, I have replaced the shims and will leave the whole thing overnight to be sure the epoxy sets fully before the job of refitting the coil and cone......so that leaves nothing to do but empty another bottle of sauvignon blanc, and as the sun is shining outside I may even fire up the barbque
epoxy held up overnight so refitted the dustcap, dropped some weights onto it to hold it in place.
the weights where also required to bring the two edges of the cut diaphragm together for gluing.......this now leaves a bit of soldering and it will be time to test it out
looking inside at the crossovers it seems rude not to replace the bipolar capacitors while all this is going on, Martin can you provide me with a set of replacements for two speakers?
all hooked up and tested.....the speaker sounds fine, not sure yet how I feel about the difference between my 3800 units and this one, will need to replace the crossover caps,connect both speakers up and compare the sound when everything is complete. the next thing is to replace the grill material on both speakers as its looking a bit tired right now.
Craig: looking inside at the crossovers it seems rude not to replace the bipolar capacitors while all this is going on, Martin can you provide me with a set of replacements for two speakers?
Yes.PM or email me.
Nice work on the woofer!
Martin
Received the capacitors yesterday, thanks Martin, and the new grill cloth arrived today.......will get onto it tomorrow, now I know how these dislodged magnets can be sorted I will keep an eye out for another to keep as a spare........although I have epoxy glued the magnet and base plate the pole can still move inside.
Stripped away the old cloth and gave the plastic support panel a good scrub, the old cloth comes away very easily.
New cloth secures from an ebay site feels like good quality and looks pretty good against the remaining old grill, truth to tell my partner Debbie cut and fitted the new covering, more of a girly type of exercise really ;¬)
She got the corners quite neat too
Finished items ready to go back, I shall address the marks and scratches on the surfaces of the cabinets next before I recap the crossovers.
Got a little distracted from my efforts on the latest BM6000 recently due to a slight mishap, knocked on of my 4 S45-2 speakers over and as you would expect dislodged the magnet, really should have glued them all up as I received them (but of course "it will never happen to me"). This repair is a pain to go through as it involves lots of fiddling around with paper shims and gripping in vices and so forth......so I got to thinking there has to be a better way, how do the maunfacturers do this?.....they must use a jig of some sort. A bit of digging on the "information super highway" revealed that building a jig to centre the coil magnet of a speaker had been done quite often before.....so measured up the diameter of the coil magnet and ordered a 4" NB (nominal bore) piece of plastic pipe, closest I could get.
I cant cut very straight with a saw so taking a hose clip I measured 1 1/2" from the end of the pipe and tightened the clip to help me keep a straight cut.
Finished up with a 1 1/2" collar
My original idea was to make cuts into the "in board" end of the collar and use the hose clamp to tighten around the collar and grip onto the magnet, this didn't work out well and I couldn't get the required reduction in diameter I needed to tightly grip the collar and magnet in place....so drilled and tapped 5 off 5mm holes around the bottom and used machine screws to hold the collar to the magnet instead. This worked out better, then drilled and tapped another 5 off holes complete with screws for positioning the magnet base plate. The manet core was still firmly attached to the base plate so no worries there.