There I am, sitting back relaxing after my evening meal, listening to an album playing on the Beogram 6000. I am in that "I'm about to doze off state" where you know something has happened but you're not sure if it's a dream or not.

Wait a minute, "what's that acrid smell of smoke", I thought and "why has the music stopped"?

I come to my senses to find that the dust cover on the Beogram looks like one of those "pea souper" type fog banks perfected only by old American films about London. You know what I mean.

I jump up a pull the plug, the Beogram 6000 is dead.

Never has a state of euphoria been so short lived!!

Ouch. But the smallest components can make a lot of smoke, so it doesn't need to be drastic damage!

tournedos:

Ouch. But the smallest components can make a lot of smoke, so it doesn't need to be drastic damage!

I'm hoping so Mika. Maybe a capacitor if I'm lucky. It's complely dead so I'm thinking power supply.

I'll probably take it apart tomorrow.

Hope it's not too bad Graham.

Craig

I think I have 2 spare power supplies Graham 1 for each type of BG6000 - tangential 4000 based one & the radial one. The one for the BG4000 based 6000 is from (I think) a 4002 & hopefully will be the same as yours (I know there were several versions of the 4002).

Chris.

It's a 6000 Quad Tangential Chris. I'll be in touch when I get the top off, you could be my Saviour!

Many thanks

Graham

Put some pictures up of the damaged areas - I have lots of parts, and I'm sure I can help

Menahem

Thanks Menahem, the only damage at the moment which is visible is a blown 250mA fuse on the incoming mains supply. Need to ascertain exactly when this fuse blows to help me get an idea of where to look. Need to get some of these fuses before I can proceed, otherwise I could be looking everywhere.

Suspect the solenoid circuit. 1R56 looks as if it has been getting a bit hot!

Graham

When fuses blow, it's pointless to just put in new fuses without sorting out the problem. You'll just blow the new fuses as well.

A smart solution is to wire a 60W bulb in series with nour AC lead to the mains.

In your case here, just wire a 60W bulb into where the turntable fuse used to be, with a long wire going away from the turntable.

When you switch on the unit and the problem still exists, the bulb will illuminate. As the 60W bulb absorbs the "short" energy, this will allow current to flow inside the turntable without destroying anymore components. Feel around for very hot components, and replace them. Those are likely the cause.

When you can switch on the turntable, and the 60W bulb NO LONGER illuminates, then the problem is solved, and you can replace your new fuse without fearing that it will blow.

Menahem

What a good idea!!

I have a visitor at the moment so I'll try later on tonight.

Thank Menahem

The arm solenoid would appear to be the source of the acrid smoke - it has certainly been hot! Will need rewinding!

The left hand end of the arm does NOT make contact with the micro switch under any circumstances - should there be some sort of plastic shoe on the end of the arm to make contact with the switch??

I will get the hang of this posting photos on day!

Getting better at it!

joeyboygolf:

I will get the hang of this posting photos on day!

No problem there, that's one quality closeup!

I have an early AC motor version (type 5505) as well, and it seems very much the same, although the switch arm is plastic (and has been repaired long ago, never noticed that before).

But... you seem to be missing the plastic bit on the switch itself! If the switch never tripped, I believe the control circuitry supplied the solenoid with full power all the time, causing it to melt. It is supposed to work a bit like the starter solenoid in cars - full power to kick it in, then much less to keep it in.

You'll probably need a new solenoid if the winding insulation has melted, and perhaps the control transistors / resistors as well...

I have found the black plastic laying in the bottom of the box. It has broken such that it will not stay on the switch. Will need to fabricate a plastic widget to either fit on the switch or possibly fit on the arm.

Could possibly araldite the original to the switch but I am not in love with that idea. What do you think??

I will need to think about it. Have talked to Tim J and Nobby who both say "just get some same guage wire and rewind it". Sounds easy !!!

I will look at associated transistors as they could be knackered (technical term).

Well as long as the fix positively works and stays on... hard glue on the switch itself might make it harder to operate, looks like the metal bends in operation although there is a separate spring as well. So I guess I would rather attach a suitable blob to the actuator arm.

I used to make electric magnets etc as a kid, and still remember what an annoying job winding them neatly is unless you make up a winding machine / jig (and have new wire without any kinks instead of something salvaged from old transformers!). Other than that it will certainly be possible to rewind it, the wire isn't even very thin.

If the fuse blew in time the control circuitry might still be fine.

Quick and dirty fix - OK

But remember that that arm didn't just fail willy-nilly - It was very stressed to the point of cracking and then failure. I would take apart the entire mechanics there - it's not a difficult job at all - and clean all the old gunk out, put new lithium grease on, and then reassemble them all.

Also, get hold of an ESR meter - I'll lay 90-1 that most of those red tantalums and all the electrolytics on the control board are shot, and aren't doing anything healthy for your unobtanium transistors.

Check out my BG6000 pdf on my website, it's got lot's of insights on the things you need to do here!

Menahem

I don't remember the circuit that well so I don't remember if the switch has ground connection at the center contact but the
metal actuator arm would surely short the switch to ground now that the plastic blob isn't there to insulate. That could also
have caused some distress.

Martin

I am not surprised that the plastic blob disintegrated and fell off. The design of the fixing was particularly poor with a very small amount of plastic left to hang on to the spring and the only tension that it is under in normal use is that provided by the switch spring itself.

I have fixed a plastic blob (cut down foot from a Beolab 2500) onto the arm with superglue as a development solution while I think about a more elegant and functional method.

I have now to find a way to measure the wire diameter for the solenoid rewind?? I need to find a local contact with a small micrometer. Not easy in a predominently farming area!

**edit** found one!

Once you start to unwind it, you could carefully lay out 10-30 turns on a round tube and measure the width with a regular caliper. Round down to next seemingly sensible standard size to account for the insulation layer and other imperfections.

But are you actually sure that the solenoid has melted? Probably is, but it would be a lot of work for nothing if it isn't... perhaps you could test it by disconnecting it from the rest of the circuitry and feeding it some 20-30V from a current-limited power supply (or through a suitable resistor, car light bulb, or something).

I've used Polymorph in the past to fabricate plastic parts/widgets with successful results. You can either create a mold using a lump of it and pressing the original into it to make the impression, let it cool down and push more into the mold to duplicate the original...or hand create the original using a hot blade on a cooled lump of the stuff. It's suprisingly tough once cooled down.

Stonk:

I've used Polymorph in the past to fabricate plastic parts/widgets with successful results.

Never heard about that stuff before. Thanks for the tip, that was my quickest eBay purchase so far!

tournedos:

But are you actually sure that the solenoid has melted? Probably is, but it would be a lot of work for nothing if it isn't... perhaps you could test it by disconnecting it from the rest of the circuitry and feeding it some 20-30V from a current-limited power supply (or through a suitable resistor, car light bulb, or something).

I disconnected one end of the solenoid winding and measured the resistance out of circuit at 2 ohms which means that if the supply voltage is 22.8v then the windings would be drawing 11.4 amps ( please excuse my high school electronics - it was a long time ago! ). If I am correct then that is too high.

Can you measure the reistance of your coil Mika and are my calculations correct?

I measured mine with the solenoid still connected to the rest of the circuitry and got ~9 ohms both ways - so there's no way it could be any less when disconnected and the DC resistance in yours seems way too low. I guess it is safe to say that it has internal short circuits.

Thanks for you help.

I spoke to Tim Jarman last night and as soon as I mentioned smoke, he was adamant that the solenoid would be the problem and caused by the switch not activating, thus holding the solenoid at max voltage for too long.

He indicated that the situation had possibly been happening for some time and the windings finally gave out in despair.

He has apparently had to rewind several in the past and modify the arm with a plastic affair to ensure that the switch activated when the arm had travelled sufficiently far.