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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi. It looks like there it can be a bad welding in the suspected coil. The melted soldering and the black marks clearly seen on the pcb board around this welding may had been produced by a false / intermitent contact on this welding that may has been producing electrical sparks. If this is the case it could be easily fixed (before it causes a serious damage to the amplifier board, if continously working in this state).
Try this way:
- use alcohol (preferably isopropyl alcohol, but f you don't have it just use regular medical alcohol) to clean this welding's surrounding in order to eliminate the melted soldering remains (clearly seen in the photograph as small soldering balls) and the marks left by the electrical sparks on the pcb
- use a soldering iron and regular soldering to resolder the suspected welding (the four weldings of the suspected coil are big enough to make this an easy task).
- once the repaired /resoldered welding looks like a good welding use alcohol again to clean the surrounding
If this doesn't fix the problem the reason of the static noise will be much more difficult to determine and I will advise to replace the board... but I think there is a lot of probabilty that this procedue could fix the problem.
Good luck !!
👍 i might have a go at trying to fix it. I have zero soldering experience but i do watch luis rossman on the tube from time to time so i have a pretty good idea at what im going into. It seems to me i have to remove the old solder by using a wick then apply new solder. What is more a mystery to me is can i get away with doing only the bad one or do i need to do the other three on the same coil for it to be thorough enough? Ive already checked up for spares from b&o and will order those if procedure doesnt work.
as a sign of appreciation for your tip i will offer you the old board for free (postage only from norway to wherever you are) if i end up replacing it. (Xocas)
It will not be strictly necessary to remove the old solder; just adding new solder in order to get a good welding should be enough. (but first of all you must clean the remainders of melted solder around, presumably produced by the electrical sparks due to the bad contact).
The foto looks like there is only a bad welding, so it should be no necessary to redo the other three... I will not redo the other three, but you can try if you feel confident and want to be sure.
Soldering electrical componentes is not such a difficult task. The "secret" is to apply heat enough to the parts to be connected and not only to the solder (but no to the point of damaging the components and/or the pcb !!).
For this concrete task:
- use a 25W soldering iron (like a JBC model 30 ST or similar) with a tip of 2 or 3 mm diameter,
- plug the soldering iron, wait enough time for the soldering iron to reach the working temperature,
- clean the tip with a wet sponge, apply just a bit of solder to the tip, (the tip should look now clean and brilliant with the solder closely attached to it, without forming a kinf of "ball" due to excess of solder), if required use the wet sponge again to retire the excess of solder away from the tip,
- apply the soldering iron tip to the coil souspicious welding, wait 1 or 2 seconds until the solder melt, be sure to reach the coil terminal with the tip of the soldering iron to assure that you are applying heat to the coil terminal also,
- add now new solder by approaching the solder wire to the tip of the soldering iron and melted solder; be sure the new and old solder (if not previously removed, as you said) are completely melted together, wait one second, take out from the solder the soldering iron tip... and that's all.
The solder should flow freely; if it’s forming balls then there is likely a problem with the tip, the temperature, or (sometimes) the surface. A finished good welding must look brilliant and take a form similar to a hill, not like a ball (something like this "^" and not like this "o"). The complete task should not take more than 5 or 6 seconds.
Do NOT use lead-free solder. You should use lead-free ONLY if you are experienced using it and confident. Lead-free solder requires a highermelting temperature and thus is more difficult to use. I will not recommend lead-free solder for first-time practitioners.
I appreciate very much your offering but don't worry about that... I hope you will be lucky and that the only problem with the board is a bad contact in the coil.
Procedure completed without problems. A observation is the copper colored wires that goes around the ring end then passes through the pcb with solders on both sides of the pcb is all silver colored except for the one where the balls where(picture in media). On the backside the solder joint cleaned up nice and got all silvery. On the front side underneath the ring its another story. The solder wouldnt stick to the wire at all, and i noticed its copper colored alle the way through the pcb unlike the others where theres a silver color from approximate 0.5cm before it enters the pcb. After working it abit i ended up just scratching it badly and it may look like i got the solder to stick to it. After reassemble there is still sound from the speaker. And no static as of yet(1 hour in) 👍 so it may seem like problem is gone. I will update post if static comes back.
added a new picture to media section. Dont have macro option on camera but i think it will show the problem.
I think there are pcb copper etches contacting the coil terminals (at least some of them) in both sides of pcb. This is the case of the suspicious welding. But if both sides of solder are in good contact through the pcb hole there is no problem if the solder makes contact with the coil terminal (the end of the copper colored wires wounded around the ceramic ringl) only in the backside... the electrical contact with the coil's copper wire is guaranted. And if the solder has flowed ok and melted in both sides of the pcb (to contact to the other pcb etches that connect with other components) things will be fine.
In fact, the solder wouldn't stick to the wire (on the front side, underneath the ring) because of the enamel isolating cover, but the electrical contact with the wire was done in the other side of the pcb. As you "scracthed it badly" the isolating enamel was removed and so the solder could stick to the inside wire, also in this other side of the pcb..
Surely you have notice that both sides of the coil's green ceramic ring are glued, using white silicone, to the pcb. I guess this is in order to cushion/inhibit mechanical vibrations (that could be produced by the sonic pressure inside the speaker). These mechanical vibrations of the coil theoretically could broke, at the end, the solder and give a bad welding with intermitent loss of contact. May be this was the original cause of the problem. If by pushing it with your finger you feel like this coil looks looser than the other one it could be a good idea to add a bit of silicone to it.
Congratulations for now... hope this has fixed the problem !!
Do you know where I can get the 8003195 board?
My local dealer is not allowed by B&O to sell spare parts any more and cant even access them in the computer system.
Here I give you the contact data of an offcial dealer in Madrid (Spain) where I got a pair of 8003195 boards on July 2020 and on September 2021. I kept very satisfied wth their management.
Miss. Maricarmen (adminisrative offcer) answered the phone and e-mails with kindness and profesionality.
I don't know if they send parts abroad (out of Spain).
sertec electronica
info@sertecelectronica.com
T. (+34) 915 399 081
https://www.sertecelectronica.com/servicios/audio/
Calle Gral. Palanca, 31 28045 Madrid, España.