"the only trustworthy man in whole Finland 😁"

Loved that!

Yes, in B&O technical.....

lausvi wrote:

 

Pekka, I'd suggest you contact a shop like http://www.classicaudio.fi and ask them for help or to point you to a nearest repairman. I know they have at least one B&O-specialist whose services I have used myself and I am sure you'll get someone to have a look on your Beogram.

 

Hi,

sure, I was there yesterday and today! (I live nearby)

I had been looking for a Quad amp and/or possibly a CD-4 capable turntable (record player) for some time. I would have gladly bought locally, especially for this kind of problems. Now I bought from a dealer (in Denmark, where else) and he seems to know his stuff, but still this happened. :(

It did not work even for 24 hours, with Classic audio (I bought an Akai GX-630D-SS from them and a bunch of vintage speakers) I would have a complete one month warranty.

here the problem is that this is a complex devoce that was working 100% pergectly before it shut down. Why could it not be just the Power supply / Transformer? (Sorry for short, and strange typing, darn iPad, good for reading, BAD for writing...)

Menahem Yachad wrote:

Pekka

I have received your request for help.

I would start by looking at 2 areas, which draw high current - the DC motor which moves the arm to the left or right - if there is some obstruction to the movement there, and also the solenoid coil which drops the tonearm, which should measure a minimum of 9 ohms.

The input to the transformer at 100V - completely unreasonable - aren't you in a 230V country? 

Check your Multimeter.

The only other man in Finland whom I would trust is Mika - known here as tournedos.

If there is any other way I can help, feel free to ask.

Regards

Menahem Yachad

Hi,

Thanks. I will look into these and take measurements. The motors seem to move freely, I can test them too. I had to move the arm to get the disc out, as it had stopped in the middle of a record. I could quite easily rotate the wheels to slowly roll the arm back.

Yes, I have several multimeters, and this is the best of those. I use them on DC stuff (car electronics) quite a lot. The wall socket and extension cord with power surge protection show 230V AC. That's why I asked about the transformer voltage originally as I did not know what happens inside the voltage selector switch housing etc. Now I have complete schematics and can see what's supposed to happen and where.

I suspect some shorting or leak to the ground as the other fuse terminal (the right hand side, the one that burned) shows almost 14V AC to about all terminals found anywhere inside the Beogram. Including the connectors for the audio output socket, where I can measure 13.9V AC between the ground connection and the mentioned RH fuse and 12.5V AC between all four channels and the fuse.

That's why I was so confused about the whole voltage issue and started thinking the whole thing operated with AC!  :D

But my logic would say the transformer has a short to the ground of the whole and thus I can measure AC voltage across anything and the fuse holder.

Yes, I agree, fixing a board and putting it back in a situation where there is unwanted voltage across the whole board or the whole casing is not something I would do either. That's why I want to find out more and once all places show correct connections and correct voltage then the damage can (hopefullly) be repaired.

Cheers!

Pekka T.

If you bought from a dealer (shop/business), the unit comes with a certain warranty.
In that case, I suggest you contact the dealer.

Martin 

Dillen wrote:

If you bought from a dealer (shop/business), the unit comes with a certain warranty.
In that case, I suggest you contact the dealer.

Martin 

Hi Martin,

I did. And of course I contacted him immediately and told him in great detail, how the wooden shipping box had lost one "leg" but the box itself was intact, everything inside was absolutely fine, complimented him on great and careful packaging (the lid for the Beogram 6000 has on one crack in a corner, but that may have been there for decades) especially the cartridge and needle that had extra padding and taped together over the regular protection cover for the cartridge and needle.

I also told him how I let the box get warn first in our office (21.9°C) and also several hours after opening the wooden shipping box and only then when everything was room temperature I mounted the equipment on a steady, good table surface and then plugged in the cables and switched the power on etc.

I also told in great detail what I did and what happened, how the Beogram just stopped suddenly in the middle of playing a record and how I replaced (carefully) the 0.25A 250V fuse and how then it triggered the power protection on the extension cord (and other equipment also went down, except my laptop as it was then running on it's battery) That is also why I started to measure all connections as it seemed there was indeed an electrical problem.

I do not wish to have the Beogram shipped back and forth, I will do it of course if I have to, but like I wrote, it cost me ca. €150,- euros (1.100,- DKK) just to get it here. If we have to ship it back and forth, there's always the risk of further damage AND it will cost worth the unit itself just to get it shipped there and back etc.

I did get a response from him and did get in touch with Alain who has serviced/restored the Beomaster 6000 Typ 2702 and got a PDF about the details of the restoration (looks like really good work) and other material. That unit had from start when it arrived in my office, a rather disturbing buzz in the Left rear channel, and still has whenever the Rear speakers are switched on, regardless if there's signal or not. And all three other speakers, incl. Right rear, sound fine, but this Left rear just keeps buzzing and does not produce any other sound. Now that might be the case of another thread or discussion, but for now I AM trying to solve that between the Danish dealer who sold me the whole lot and Alain who had restored it and me.

But for this Beogram 6000 Typ 5502 Alain has nothing to do it, it too has been serviced at some point (one screw missing from one of the boards, and it was not loose inside the housing. Yes, I would like to have it working again, but no I would not like to ship the whole unit, unless the dealer pays the shipping, which I think may be unlikely. If I just return it, I would loose the wooden shipping box (could be handy for shipping another Beomaster 6000 Typ 2702 for restoration) and the shipping cost one way (anything between €50,- and €100,- euros I think one way) and possibly then I would not have a Beogram 6000 wityh a CD-4 demodulator anymore, which is what I wanted in the first place.

Sorry for this much explaining, but I thought maybe you did not realize that doing this checking myself and seeking help from the beoexperts and beolovers was kinda my last chance, ok?

Cheers,

Pekka T.

Dillen wrote:

If you are in Finland, your mains is not 100V AC.
In Europe mains is 220-240V
If you measure 100V AC with your meter across your mains in Finland, your meter is not working (or you are not using it right).

Martin

Hi,

Thank you for pointing that out. And like also pointed out, that was really odd.

That's now fixed. :)

Perhaps this would explain, why the unit was set to 220V although it came from Denmark, where I believe they also have 230V AC 50Hz like we do. LIke you all kept telling me that it should read 230V AC and doubted my tools and my knowledge it turned out to be the voltage selector. I opened it and then measured the voltages again. Yes, input cord obviously had 230V AC just like the wall socket and extension cord, BUT the other connection for the voltage selector only showed 100V AC. I switched it back to the 220V setting and now I have 230V AC on both terminals and both fuses. About 232V or 233V to be more exact.

So one problem down.

But the rectifier still outputs ca. 0.5V DC instead of 25V DC and the input /the two thin black cables show erratic AC readings. So I take it that the transformer has to be toasted. The rectifier (ITT B80 C3200/2200) shows a resistance of about 16kΩ one way between the AC and the DC terminals and about 46kΩ the other way.

Before I intend to use an auxiliary power supply or replace the transformer with anything, I will of course hunt down all of the unwanted voltages and connections to the ground where there should be none. All good ideas are welcome. :)

Pekka T.

Menahem Yachad wrote:

I would start by looking at 2 areas, which draw high current - the DC motor which moves the arm to the left or right - if there is some obstruction to the movement there, and also the solenoid coil which drops the tonearm, which should measure a minimum of 9 ohms.

Thanks Menahem, the mains voltage issue is now sorted out (voltage selector switch) and I looked at those you suggested, they both seem to operate ok, the motor gives a static resistance of 21Ω and (unfortunately?) the coil for the dropping tonearm gives a static resistance of 8.6Ω (Ohms, maybe it's better not to use the symbols on web forums, with no UNICODE guarantee across readers).

You say it "should measure a minimum of 9 ohms, now it measures 8.6 ohms, Could that blow a fuse? Or does it just mean the for the near future I would need a) a new coil?  b) someone really handy rebuild that coil for me?

I'll need to find Mika then, unless he happens to be the same guy the Classic Audio folks use, in which case I have found him. :)
The biggest problem at the moment seems to be the clearly non-functioning transformer. I guess someone can also rebuild those?

Cheers!

Pekka T.

TR28 is part of the motor drive circuit – which means that the motor was subjected to severe load, which caused that transistor to heat up and burn the PCB.

So, you MUST look for the cause in the motor area – something prevents the carriage from moving freely to the left or right.

Hi,

thanks again, ok I will look. Now of course I have the tonearm rolled all the way to the right. It was a bit over half way to the left when it quit. But it had successfully played two and a half LP's that same day, and two 45's without any glitches. Well, perhaps that proves nothing, except that all the automatic functions were working for half a day.

I don't have the schematics here, I can look tomorrow and roll the tonearm all the way to the left to see if there could be any obsctruction or something stopping it. Which is the TR28? How do you think the resistances measured are? And which transistor burned out? I thought the transformer was so far the only thing definitely damaged?

Pekka T.

TR28 is the burnt transistor, which is shown in the picture which you sent me.

TR28 indicates where the problem occurred, in the motor circuit, and probably due to a physical obstruction or short in the motor travel.

IF the transformer is damaged, then that was a secondary effect of the stress imposed on the entire electrical circuit.

There are a LOT more parts which need to be replaced on that PCB - your thinking that there are only 1 or 2 parts to be replaced, is completely mistaken.

8.6 ohm is probably OK, based on your multimeter's error.