B&O Beovox 4703 restoration with pics

[Oldsansui441]

Hi, l have recently purchased these beovox 4703's. Two woofers weren't working when l got them, one had an open voice coil and the other had a bad solder at one voice coil to flexible lead wire junction.

I bought four more original woofers but 3 of the 4 turned up with jammed voice coils (shifted magnets). I have repaired 3 woofers so far, thinking of doing them all so l don't have to worry and so l have fully functional spares as well.

I also recapped the crossovers, replaced resistors and replaced the woofer wiring. If it helps anyone the shims used for centering the magnets are 0.94mm and shims for centering voice coil are 0.14mm.

I have them all back together and they do sound very nice indeed, l have found mids to be slightly more pronounced than the lows and highs, have my amp loudness on to compensate for this, don't know if this is normal for these.



I do have 3 questions:

-The yellow cabinet insulation (packing) is still in the plastic bags, is this normal? It kind of seems to defeat the purpose with the plastic.

-The large crossover caps that l have pictured are supposed to be 75uF, all four measured between 125uF and 157uF, surely they weren't marked "incorrectly" from Wicon factory? I have replaced many caps in amps and receivers and have seen some old caps higher in value than specified, but never double esp on a high value like this?

-I will have to re-veneer the cabinets as they are unfortunately rough, should l go with golden teak as original or perhaps American oak. I know they came out in oak and l can get this much cheaper. https://www.veneersonline.co.uk/col...eer-sheet-unglued-fleece-backed-3500mm-x300mm
Or this teak
http://www.ebay.com.au/itm/112197259361?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Or this walnut
http://www.parts-express.com/band-it-walnut-veneer-24-x-96-paper-backed--260-048

Some guidance on the veneering would be much appreciated as l haven't attempted before, should l be using iron on or would the fleece or paper backed be ok to use with a spray contact adhesive?

I appreciate any feedback. Here are some photos of my progress.

 

[Oldsansui441]

Here are some photos of the cabinets.

 

[Oldsansui441]

How about either of these veneers? They are myrtle and blackwood.

 

[GD70]

Hi, l have recently purchased these beovox 4703's. Two woofers weren't working when l got them, one had an open voice coil and the other had a bad solder at one voice coil to flexible lead wire junction.

I bought four more original woofers but 3 of the 4 turned up with jammed voice coils (shifted magnets). I have repaired 3 woofers so far, thinking of doing them all so l don't have to worry and so l have fully functional spares as well.

I also recapped the crossovers, replaced resistors and replaced the woofer wiring. If it helps anyone the shims used for centering the magnets are 0.94mm and shims for centering voice coil are 0.14mm.

I have them all back together and they do sound very nice indeed, l have found mids to be slightly more pronounced than the lows and highs, have my amp loudness on to compensate for this, don't know if this is normal for these.



I do have 3 questions:

-The yellow cabinet insulation (packing) is still in the plastic bags, is this normal? It kind of seems to defeat the purpose with the plastic.

-The large crossover caps that l have pictured are supposed to be 75uF, all four measured between 125uF and 157uF, surely they weren't marked "incorrectly" from Wicon factory? I have replaced many caps in amps and receivers and have seen some old caps higher in value than specified, but never double esp on a high value like this?

-I will have to re-veneer the cabinets as they are unfortunately rough, should l go with golden teak as original or perhaps American oak. I know they came out in oak and l can get this much cheaper. https://www.veneersonline.co.uk/col...eer-sheet-unglued-fleece-backed-3500mm-x300mm
Or this teak
http://www.ebay.com.au/itm/112197259361?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Or this walnut
http://www.parts-express.com/band-it-walnut-veneer-24-x-96-paper-backed--260-048

Some guidance on the veneering would be much appreciated as l haven't attempted before, should l be using iron on or would the fleece or paper backed be ok to use with a spray contact adhesive?

I appreciate any feedback. Here are some photos of my progress.

I don't think those cabs warrant e re-veneer. All those corners and edges can be repaired with veneer spliced in where the damaged areas are.
See my thread on my recent AR3 project. Lots of pics showing the process. This is a lot less work than re-veneering, unless you want a totally different type of wood.
My thread link. I hope this helps.
BTW, very nice work on those woofers!. I'm also wondering if those caps are why the mids are so pronounced. Something is wrong there with the cap value and your reading.
My thread link. I hope this helps.
Glenn
http://audiokarma.org/forums/index.php?threads/toilet-paper-stop-yields-a-pair-of-ar3s.735482/

 

[Oldsansui441]

Thanks heaps for that GD70, you are a champion, just read your entire thread with great interest, that is a huge help, cheers. Maybe l will get a small piece of new golden teak and follow your lead in regards to repairs. I think you state in your AR thread that you are best to cut damaged veneer section out at an angle, is this correct or is a straight cut along the grain easy to hide also?
Thanks for your comment on the woofers, l will have spent many hours after l have completed all including the spare ones, but they are not exactly thick on the ground so will be good to have extras.

Yes l am not sure what is going on with the original 75uF caps, all other caps tested within 20% of value.
Thanks again for your help, l really appreciate it and all the best with your "new" speakers. Like your thread title also

 

[Oldsansui441]

The more l use these it seems the better they sound. I have some B&W Matrix 2's that l think these would give a run for their money, haven't A-B'd them yet though!

 

[LewisGoudy]

Hi, l have recently purchased these beovox 4703's. Two woofers weren't working when l got them, one had an open voice coil and the other had a bad solder at one voice coil to flexible lead wire junction.

I bought four more original woofers but 3 of the 4 turned up with jammed voice coils (shifted magnets). I have repaired 3 woofers so far, thinking of doing them all so l don't have to worry and so l have fully functional spares as well.

I also recapped the crossovers, replaced resistors and replaced the woofer wiring. If it helps anyone the shims used for centering the magnets are 0.94mm and shims for centering voice coil are 0.14mm.

I have them all back together and they do sound very nice indeed, l have found mids to be slightly more pronounced than the lows and highs, have my amp loudness on to compensate for this, don't know if this is normal for these.



I do have 3 questions:

-The yellow cabinet insulation (packing) is still in the plastic bags, is this normal? It kind of seems to defeat the purpose with the plastic.

-The large crossover caps that l have pictured are supposed to be 75uF, all four measured between 125uF and 157uF, surely they weren't marked "incorrectly" from Wicon factory? I have replaced many caps in amps and receivers and have seen some old caps higher in value than specified, but never double esp on a high value like this?

-I will have to re-veneer the cabinets as they are unfortunately rough, should l go with golden teak as original or perhaps American oak. I know they came out in oak and l can get this much cheaper. https://www.veneersonline.co.uk/col...eer-sheet-unglued-fleece-backed-3500mm-x300mm
Or this teak
http://www.ebay.com.au/itm/112197259361?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Or this walnut
http://www.parts-express.com/band-it-walnut-veneer-24-x-96-paper-backed--260-048

Some guidance on the veneering would be much appreciated as l haven't attempted before, should l be using iron on or would the fleece or paper backed be ok to use with a spray contact adhesive?

I appreciate any feedback. Here are some photos of my progress.

 

[Rob Miller]

Oldsansui441 - Hoping for some advice...

I found a pair of 4703's at a thrift store here in the US and fell in love with the sound they produce. All of my woofers have been refoamed at some point with rubber surrounds but despite that, one of my boxes has two blown woofer drivers. I bought another extra single 4702 box from ebay for parts that was supposedly good but it has two blown woofers too. Apparently a common issue. Do you know if refoaming these again would solve the buzz from the blown drivers, or if there is a good source for replacements? I already have way too much money into these but they are for a recording studio for casual listening with our clients and I'd like to get them working at 100% again. Plus they are beautifully made. If I send you the drivers would you be able to fix them? I have a spare set I could part with for any amount of time needed.

Thanks in advance!
Rob

Hi, l have recently purchased these beovox 4703's. Two woofers weren't working when l got them, one had an open voice coil and the other had a bad solder at one voice coil to flexible lead wire junction.

I bought four more original woofers but 3 of the 4 turned up with jammed voice coils (shifted magnets). I have repaired 3 woofers so far, thinking of doing them all so l don't have to worry and so l have fully functional spares as well.

I also recapped the crossovers, replaced resistors and replaced the woofer wiring. If it helps anyone the shims used for centering the magnets are 0.94mm and shims for centering voice coil are 0.14mm.

I have them all back together and they do sound very nice indeed, l have found mids to be slightly more pronounced than the lows and highs, have my amp loudness on to compensate for this, don't know if this is normal for these.

 

[Oldsansui441]

Hi Rob,

Yes they are nice speakers and well worth getting up and running properly. Your 4703's should have had rubber surrounds all along, it is the previous model 4702's that have the foam surrounds but they are identical drivers. I have a pair of 4702's here that l have replaced the foam surrounds with rubber surrounds as per the 4703's for longevity.

You are correct, these and other Beovox models are notorious for the magnets shifting as the factory glue was inadequate. This is why you can buy replacements but if you have them shipped they will likely fail in transit. The 4703's referred to in this thread experienced magnet shift when l originally bought them, after just a one hour car trip home. I run a bead of two part epoxy around both magnet edges on all Beovox's l have owned or will own in the future.

Your woofers with the rubber surrounds won't require new surrounds but will have to have the magnets and voice coils re-centred if the voice coils are still o.k (which they usually are). I would be happy to help you out but l think the cost of postage both ways plus the excessive postage times currently would probably be prohibitive. Are there any speaker repair shops in your area?

Another option is sourcing a pair from Martin at Beoparts (no affiliation but a nice guy that l have bought from before). If he has a pair he will glue the magnets before shipping.

 

[Rob Miller]

Just knowing what causes the issue is a great help. I will take the drivers out and see if I can realign the magnets. Is that where the magnets connect to the basket or in between the magnet's metal plates where the shift happens?

The closest BO repair shop (California) quoted much more than they are worth to fix.

Thanks!

Hi Rob,

Yes they are nice speakers and well worth getting up and running properly. Your 4703's should have had rubber surrounds all along, it is the previous model 4702's that have the foam surrounds but they are identical drivers. I have a pair of 4702's here that l have replaced the foam surrounds with rubber surrounds as per the 4703's for longevity.

You are correct, these and other Beovox models are notorious for the magnets shifting as the factory glue was inadequate. This is why you can buy replacements but if you have them shipped they will likely fail in transit. The 4703's referred to in this thread experienced magnet shift when l originally bought them, after just a one hour car trip home. I run a bead of two part epoxy around both magnet edges on all Beovox's l have owned or will own in the future.

Your woofers with the rubber surrounds won't require new surrounds but will have to have the magnets and voice coils re-centred if the voice coils are still o.k (which they usually are). I would be happy to help you out but l think the cost of postage both ways plus the excessive postage times currently would probably be prohibitive. Are there any speaker repair shops in your area?

Another option is sourcing a pair from Martin at Beoparts (no affiliation but a nice guy that l have bought from before). If he has a pair he will glue the magnets before shipping.

 

[Oldsansui441]

Is that where the magnets connect to the basket or in between the magnet's metal plates where the shift happens?

The shift normally happens between the magnet and the plate/s, not the plate to basket.

The closest BO repair shop (California) quoted much more than they are worth to fix.

That's no good, yeah l hate to think what a B&O repair shop's hourly rate is these days, if you get stuck a specialist speaker repairer will prob be a better & cheaper option.

Yes definitely give it a go yourself, it's not that hard just a little time consuming. You may not be able to remove the spider glue where it meets the basket, if this is the case just make a neat cut right around the spider about half way up it's outer edge. It can then be re glued later at this cut edge.