[hcraig244]

I’m surprised the speaker gives any sound whatsoever….the magnet has clearly shifted, I can sort that out if you get it to me.

Craig

[hcraig244]

Have you connected anything to the inputs to determine if the problem is across everything or just the FM side?

[hcraig244]

The metal epoxy has turned out a little lumpy, which in other applications may be a problem….not with this one however. Dust cap back on with some Aleene’s tacky glue, useful if in the unlikely case it has to be removed again. Ready to be dispatched back home!

Craig

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[hcraig244]

I will leave this to set hard, checking that the cone continues to move freely all the time, then run a bead of the metal epoxy glue around the entire circumference of both magnet and rear plate to provide additional strength for future knocks. Following the above trauma the coil still gives a resistance reading just below 4 ohms…..

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[hcraig244]

moving swiftly on the custom made Jig can be mounted and the upper screws tightened on the ferrite magnet to hold it securely, centred roughly in the middle with the lower set of screws resting on the top of the magnet, then turning everything upside down and viewing the core position through the dust cap aperture the lower screws can be adjusted to centre the core within the coil, this can take 10mins or so as it involves adjusting a screw and its opposite screw to effect the balance.

I have tried the other method using thin strips of card inserted into the coil to centre the core without much, if any, success….my thinking was that speaker manufacturers wouldn’t use bits of card to do this so there had to be a better way.

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[hcraig244]

Yet again the engineers vice has been dragooned into service, the plate and core are gripped in the vice jaws just below the level of the jaws, about 3mm, the epoxy can then be applied to the plate face and with a very firm grip with both hands on the speaker frame the whole assembly needs to be lowered down onto the upright core, sighting the alignment through the removed dust cap apperture. The magnet is apt to grip the frame violently so a firm hold is required during alignment…..once the core is within the coil the frame can be released to allow it to attach itself to the vice jaws….then one simply unwinds the vice handle and the plate jumps up and into place.

 

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[hcraig244]

On reflection I’ve decided to use regular epoxy for the fastening of the core and rear plate to the ferrite magnet, this is due to the metal solution manufacturer boasting 5min  adsjusting time along with 2hrs hardening time…..it may take longer than 5mins to align everything and I dont want any pressure ;¬)

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[hcraig244]

With all due respect I found the above very funny….it’s typical behaviour for one of these decks! they can be so frustrating…I have spent many hours going over and over a fault finding exercise and getting nowhere, and as you say things can seem to get worse despite your best efforts….your issue sounds like more than one problem, possibly both being intermittent which are the worst kind.

My advice, for what its worth, would be to confirm the p0wer supply levels for 6 and 24 volts at the voltage regulators….unstable supplies can wreak havoc on the logic board, a failing/leaking smoothing capacitor will cause this as will a failing voltage regulator transistor, I have suffered all of these failings. The logic board itself and the associated IC chips are very reliable and seldom fail, my experience has been most issues can be traced to power supplies dropping below the specified threshold and faults associated with the switches and the small plastic spigots that can stick and hold the leaf switch in the wrong position…and also there is the real possibility of a bad connection between the wiring loom and the control panel….I have had one case which was resolved by resoldering all the connections from the wiring loom to the control panel connection terminals….I have no idea which connection was poor or dry but on completion everything came good…..

Stick with it…..send pics and updates as there are lots of very capable members in here who will advise/help you ;¬)

Regards Craig

[hcraig244]

Decided to try this new (new to me anyway) metal epoxy glue, bit more expensive but gets good reviews. Manufactures claim it sets in 5mins and is hardened after  2 hours…..yeah righto! I will leave it set overnight.

most important thing is to re attach the magnet to the frame the right way around, the polarity is important. The magnet needs to be central to the coil but doesn’t need to be exactly central, the precise centring of the core within the coil is the crucial part of the exercise.

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[hcraig244]

Ok

Next step is to remove the magnet from the plate that the core is attached to and remove all the old adhesive from all the surfaces, taking care not to break the ferrite magnet in the process….

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[hcraig244]

Back on the bench the coil still measures a healthy resistance confirming no damage was inflicted during dismantling, always a worry.

As I dont have sufficient epoxy resin to hand I will have to wait until tomorrow to continue the excercise

Craig

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[hcraig244]

Knowing it was loose it was held in a vice by the rear keeper plate and with a quick firm and even lift from the speaker frame the plate and core where left behind…the cone and coil now move freely in and out with no scratchy catching

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[hcraig244]

I was even happier when I measured the resistance of the coil and it came up a little under the specified 4.0 ohms

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[hcraig244]

Came well wrapped up and taking it out revealed nothing untoward, apart from the fact that the cone didnt want to move up or down, also someone had kindly unpicked the dust cap…tricky exercise so I was happy about that ;¬)

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[hcraig244]

Its unlikely that replacing the capacitors/trimmers/lamps etc  provided within a service kit will resolve your issues, its a very good idea to purchase one and carry out said service…however the fault described above will need a little more investigation to track down. Service manuals are available to silver members on the site along with a wealth of guidance from other members, pictures are a great help too….do you have any experience with test equipment such as a multimeter to check for voltages inside the unit? do you have a multimeter?

Craig

[hcraig244]

I checked out the BG4000 recently advertised above on ebay and was quite surprised to see it made over a thousand pounds…..not bad for a sight unseen with issues, a testament to the rising interest in vinyl and the equipment required to listen to it. I may have to increase my home insurance policy to keep pace ;¬)

And thank you Peter for your kind words….your a gent.

Craig

[hcraig244]

If you can deliver it to me in person I will sort it for you….couriers wreak havoc on these decks and will cause more damage, have a punt at it. I can use one of my cartridges to test it prior to your purchasing one if your successful….good luck!

[hcraig244]

Check this out…price will inevitably go up but maybe not as high as £1500

https://www.ebay.co.uk/itm/306021586288?_skw=beogram+4000&itmmeta=01JHJXE2X0X46MFQX97VHCKV6D&hash=item47404ed570:g:pQgAAOSw0oRnetVA&itmprp=enc%3AAQAJAAAA8HoV3kP08IDx%2BKZ9MfhVJKmaF3V1lT2OD8N3cr6gD3y6JtTUnfdRrznZ6bkNI3uwDJryLU6%2FC5%2Bik5SrZJzZHROODoak10JeAtC%2FmDkVfNvlk4WFcMqCJTHdRzijCYT7MNwVDnb3L4uybJk7QUQIRj%2BInaslhTRV%2F2pnHFUZig9QzOcAaumZ9UUlfrF%2B6sbjogbr0rMkjNfpDCy5gDfnVVjAx2s6AW%2Fe9%2BOYNoW1Fvzxhh0yVUOd04CVPvCvaypGPrHu8ugQTSMePt%2Fg%2BsmG%2FHY%2FMFO2xx46UrF%2Fa%2F4SGoOmJeBFJdGgrtqChfFy7PPxTw%3D%3D%7Ctkp%3ABk9SR9CuuN2MZQ

[hcraig244]

I only have experience with the vintage equipment, dont have much interest in the more recent products….I like the Beograms 4000 & 4002, the Beomasters 4000 & 4400 and also the Beolab 5000 mostly..I did have a couple of adventures with the Beocord 5000 with some success….however these are very complicated and heavily mechanically orientated ;¬)

[hcraig244]

I do all my own repairs/restorations….with the service manuals and wealth of support available here its not as difficult as you may think, there are very few options for this work these days…out of curiosity I enquired about repairs at our local B&O shop in Yarm….was told for the vintage items they have a chap locally who will take a look at the item and give an estimate for the repairs for a standard charge of £150……just to look at it!

I advised him if he ever had anyone looking for a competitive price to give me a call…….of course he never has ;¬)

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