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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 28th Sep 2019, 11:09 am   #1
davyrocket2
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Default Bang & Oulfsen 8902

I have just been given a Bang & Oulfsen Beovision 8902,I examined and found it works very well.I removed the rear cover and found that there is a damaged capacitor it is on board 6 just below the plug for the deguassing coils ,It has a hole where the plastic has blown out and that would have had the voltage and ,uf value on it
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Old 28th Sep 2019, 11:15 am   #2
paulsherwin
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Default Re: bang & oulfsen 8902

Is it an X2 which has failed?
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Old 28th Sep 2019, 11:18 am   #3
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Default bang & oulfsen 8902 circuit diagram

hello yes its on board 6 and the items are resistor one and capacitor two .I can load a photo if someone can explain how I do this
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Old 28th Sep 2019, 11:32 am   #4
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Default Re: bang & oulfsen 8902

Hello Paul not sure what X 2 cap means ? .If you could tell me how ,I have taken a photo but don"t know how to upload it to here regards David
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Old 28th Sep 2019, 12:26 pm   #5
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Default Re: bang & oulfsen 8902

Quote:
Originally Posted by davyrocket2 View Post
I have taken a photo but don"t know how to upload it to here
See here:-

https://www.vintage-radio.net/forum/...ad.php?t=77650
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Old 28th Sep 2019, 12:58 pm   #6
ms660
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Default Re: bang & oulfsen 8902 circuit diagram

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Originally Posted by davyrocket2 View Post
hello yes its on board 6 and the items are resistor one and capacitor two .I can load a photo if someone can explain how I do this
Do you mean F1 and C2?

In the schematic I'm looking at C2 is a 0.1uf (100nF) capacitor connected across the mains input after the fuse, if that's the one you should replace it with an X Class type, X2 type being what most folks would use, the fuse is a 2 amp job (delay type "T")

Lawrence.
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Old 28th Sep 2019, 4:53 pm   #7
davyrocket2
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Default Re: Bang & Oulfsen 8902

Hello Lawrence. It's below the deguassing plug parallel to the resistor. I have just found the panel was being sold on ebay but it's found a new owner. My set is working, but I am guessing it's not going to last as the top of this cap has burnt away, so I need to obtain another of the correct type . I am also looking for another A66/540AX tube mine's OK but the A1 volts are at max, the grey scale and colour are fairly good and brightness, but for how long? I have just seen photos and it seems to be 47 uF 275 volts, does this sound correct?

Regards, David.
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Old 29th Sep 2019, 1:16 am   #8
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Default Re: Bang & Oulfsen 8902

For now, you can just remove it. It's probably a 0.47u (470n) 275VAC X2 rated paper capacitor by RIFA. Avoid paper capacitors as a replacement, just get an MKP (polypropylene) 470n X2 capacitor from a reputable brand.

What brand is your picture tube?
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Old 29th Sep 2019, 11:48 am   #9
davyrocket2
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Default Re: Bang & Oulfsen 8902

Hello Marten its a phillips tube it could possibly be the original its a one owner from 1985 . I turned up the A1 volts which brought up slight green tint so . I carefully adjusted all three colours on a black and white picture showing no tints the contrast is good, but the picture brightness is very good but the A1 is at end of its travel slightly backed off because of flyback lines .I cleaned the HT cap and it does arc slightly at first turn on but. I have some HT sealant . I will use,if. I can find a tube/ I am prepared to travel to collect or pay reasonable costs regards David Grant .
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Old 29th Sep 2019, 5:32 pm   #10
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Default Re: Bang & Oulfsen 8902

Hello Maarten I would be interested if anyone knows of the whiteline version of this set or any tubes A66/540AX they were also fiited to Grundig sets
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Old 1st Oct 2019, 10:22 pm   #11
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Default Re: Bang & Oulfsen 8902

The 540AX tubes were used in many sets at the time. In my experience only the Philips could make good tubes, and even they managed to make a lot of bad ones. Does the tube still have good focus? They usually got a soft greenish pic when they started to show wear.
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Old 2nd Oct 2019, 1:24 pm   #12
davyrocket2
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Default Re: Bang & Oulfsen 8902

the focus is still very good although I redid the greyscale as the red was high compared to the blue and green ,I have seen good and poor examples I recall that mullard white label seemed to not last very well, very poor, the green label ones seemed to last very well by comparison.
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Old 3rd Oct 2019, 12:24 am   #13
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Default Re: Bang & Oulfsen 8902

I'm not sure of the correlation between label colour and quality, I suspect the main correlation is between the factory/revision and quality. Just as with normal valves, Philips/Mullard picture tubes have stamped factory codes. Possibly, foreign made Mullard tubes have another label.
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