Beomaster 1900 Humming

20 replies

Hi there, first time posting here, but I've been repairing audio / video equipment for 30 years.  I don't see a lot of B&O products, but I'm trying to fix one for a good customer.  He bought a Beomaster 1900 off eBay that supposedly worked.  But, it has a hum that is present behind the audio and increases as you increase the volume.  The main filter cap (I believe must have been a can style) has been replaced with a 10,000uf / 35v and a 1000uf / 35v (looks like recent work).  I can't rule these out as the cause, but I thought I'd check in here first to see if anyone has any experience with this sort of failure.  I'm not really looking to re-cap the whole unit as that might be cost prohibitive.  Any thoughts would be greatly appreciated.

Best Regards,

Greg

Hi Martin, thank you for the reply.  I've attached a picture of how the unit looked when I opened it up. Someone previously had wired these capacitors in the back of the unit under the speaker terminals.  One is 10,000uf / 35v and the other is 1000uf / 35v.  I'm not seeing a 4700 or 5000uf capacitor in the unit, so I'm guessing these were installed instead? Not sure why he wouldn't have just used the correct values???  I found the schematics, but was hoping to find a wiring diagram to make sense of the way these caps are wired?  I understand about the benefits of re-capping the whole unit, but I'm a little leery about the previous repair attempt and what else might have been done to it.  Should I start with replacing those two caps with 4700uf / 50v and go from there?  The physical condition of the unit is pretty nice, and my customer really likes these units as he has now bought two of them off eBay.  Unfortunately each one has problems.... the other is blowing fuses.

Thanks again,

Greg

What a mess.
Yes, replace those two with 2x 4700uF 50V.
They are in series with thieir common pin at ground.
That makes a negative pin from one cap for the negative supply and one positive pin from the other cap for the positive supply.
Just as any other dual supply.

Email me for kits if needed.

Martin

Hi Martin, Thank you for your replies.  I'll start with those two caps and consider the capacitor kits if I'm still having problems, or if the customer wants to go for a full restoration. 

 

Best Regards,

Greg

Hi Martin,  I am  the customer in question on this thread.  yes,  we'd like to get the cap and lamp kits.  I can't figure out where/how to email you.   

 

Thanks for your help !  Larry 

Location: California

Hi Martin,  I am  the customer in question on this thread.  yes,  we'd like to get the cap and lamp kits.  I can't figure out where/how to email you.   

 

Thanks for your help !  Larry 

Location: California

Larry, I sent you an email.

Martin

Hi friends

Let's introduce myself. I'm about 60 years old, Parkinson disabled ... and HiFi belover. I've bought a Beomaster 1900-2 and I would try to revise it by myself. I think I've to recap & change some lamps. Where could I buy repair capacitance & lamps repair kits and get instructions / tutorials ? Thank you in advance. I like this forum which allows so beautiful audio equipment to get chance for a second life ...

Hi, I am repairing a Beomaster 1900 that is humming. I have a couple of questions accordingly:

- Did you get rid of the hum?

- Did you replace all capacitors?

- Did you find the bad one or were there more defective?

- Could you connect me to the capacitor kit supplier?

 

Thanks in advance

Best regards

Jens

Same questions from me. Humming 1900, looking for a caps kit.

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