Thanks Martin, I always appreciate your advice.  I will be replacing the trimmers as soon as I can source some horizontal, 100ohm items which are pretty hard to get over here.  Can you use a higher rating such as 200 or 250 ohm if the 100's prove too hard to get.  They will be less sensitive but should work??

One item that has cropped up since the 8000 has cooled down is a faulty mains capacitor on board 7, rated 330nF and 275Volts.  This has been slowly burning in the background but wasn't apparent when everything else was smelling hot.  From local information, this item is going to be hard to get.  Can you recommend some alternative values or combinations that I can try if such a capacitor is no longer available.

Thanks

Geoff

Hi Geoff,

The trimmer should be 100 Ohms. I have some in stock if you need.

That capacitor should be a Class X component. I don't know where to buy a new cap of this value but I may have a good used component in stock, I will have to check.

Martin

Thanks Martin.  This morning I managed to find a supplier of a suitable mains capacitor, class x2 and have fitted it.  The BM8000 now seems to be working well but no doubt something else will crop up soon - such is the nature of these old amps.  As for the trimmers, I should be able to source some locally but they might look a bit different to the existing ones.  At the moment, I can only source 200ohm items in the original style so I might have to wait.  Anyway, I am in no hurry to take the Beomaster apart again right now.

Thanks for the offers and the help

Geoff

I am new to the BM world and was lucky enough to have been able to acquire a BM8000 in pretty good condition.  It has similar issues to many that have posted here, hot heat sinks, burned out LEDs.  I want to thank everyone for their posts, because if it had not been for you, I would have never known the "quick" fix to the hot heatsinks.

I am starting to replace the LEDs on the displays, as they are all bad.  I will keep you posted.

Thanks!

Welcome to Beoworld and thanks for signing up as a silver member, your support is greatly appreciated !

I've developed my own techniques for repairing the original displays and it's not an easy task but please keep us informed as you progress.

Martin

Martin,

I removed the display for volume (two seven segment displays).  I used a high power magnifying glass to see the existing "LEDS" on the board.  These belong in a museum!  I can't believe they even used these, but now it makes sense why they are so vulnerable to vibration etc.  I am going to replace with smd LEDs that fit into the display's case.  I am not sure about the Vf on the LEDs but I am going to try a couple different ones.  I will also mount a socket header strip to the pc board, with a matching male header on the display.  This will make for much easier future removal/replacement.

Gerhard

Gerhard:

I successfully redid the entire display on my BM 8000 2 weeks ago replacing all segments with surface mount LEDs.

You really need to replace all of them because there the voltage between the old and new leds don't match and more importantly because the display is strobed. The new ones are much more efficient and are too bright.

I replaced all the current dropping resistors with 820 R in order to match the brightness of the original display. I prefered mine to be a bit brighter than original, but if you are picky you can go with a slightly higher value dim it a bit.

As you dim the LED the color gets closer to the original, but it isn't exactly the same.

I've taken pictures of the entire process which I'd like to share with the group but haven't figured out how to attach them.

Regards,

Derek

GDSammet wrote:

I removed the display for volume (two seven segment displays).  I used a high power magnifying glass to see the existing "LEDS" on the board.  These belong in a museum!

So what are they actually? Chips bonded in place like in 70's pocket calculators?

@auric, I'd love to see those photos. When composing a post, click on the "Options" tab and you'll see an add/update option. Only one attachment per post, though...

Here is a close up image of one of the segments with 1.7v power  applied.  I used a 105mm macro lens with a 36mm extension tube.  The "silicone chip" is less than .5mm in diameter.  The difference between the Beo LEDs and traditional LEDs is the LEDs we use now are encapsulated to prevent damage from vibration etc.  The filament wire you see is a gold strand and is very delicate.  This is the piece that breaks from vibration.

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I am wondering what value and physical size SMD LEDs you used.  I have ordered two sizes with a 2.1Vf.  I would like to see your picture too.  To attach a pic to a message, just reply, not quick reply, and click the "Insert Media" button.

Gerhard