BeoCenter Board 8002495 - UK Vintage Radio Repair and Restoration Discussion Forum

AndyJackson · 8th Mar 2017, 1:56 pm

Good afternoon folks!

I have inherited a broken BeoCenter 2002 T2101, and on inspection inside, there is a small board before the speaker amp board (ref. 8002495) that houses what appears to be a relay, and some resistors.

Resistors R101, R102, R201 & R202 along with the relay are not there! Puzzling...

I have a schematic for the 2000, but there seems to be no info on component values for this small board.

Am I blind, and not seeing them? (perhaps - Ha!)

If any of you chaps have the component values for these resistors, I'd be most grateful. Also, I have since managed to source a replacement relay...

Best Regards,

Andy.

60 oldjohn · 8th Mar 2017, 3:36 pm

Hi Andy, welcome to the forum. Nice photo, can we have a photo of the other side please.

John.

Grubhead · 8th Mar 2017, 4:42 pm

I suspect the board is a speaker protection circuit. It's likely someone removed it thinking it was causing the amp not to work. I would make a close examination of the main amp section as that would be a primary cause of amp failure. The parts were clearly there at one time.

Michael Maurice · 8th Mar 2017, 9:25 pm

I would suggest the resistors are part of the headphone circuit.

AndyJackson · 9th Mar 2017, 4:01 pm

Here's a pic of the other side of the board. Check out that scorching! Something went explosively...

Best,

Andy.

60 oldjohn · 9th Mar 2017, 6:04 pm

Hopefully the demise of R101 & R201 have saved the amps from damage, Certainly been overloaded !

John.

D_S_J_R · 9th Mar 2017, 6:49 pm

For the first few years at least of their lives, these units were very reliable electrically, the main issues being sticky tonearm lifting (dried grease turned to glue) and ubiquitous neglect of the cassette deck despite often heavy use. They're getting old now so care should be taken to check electrolytic caps as B&O rarely under-used them for longest life (I know these units were far eastern made I believe, but even so...) and many Beomasters of the 70's suffered bulging 'Roe' caps I remember...

tri-comp · 9th Mar 2017, 10:40 pm

Quote:

Originally Posted by AndyJackson

Something went explosively...

I suggest selfoscillation in the output amp(s) because of deteriorated electrolytic capacitors caused this.
Replace all electrolytic's and blown resistors.

AndyJackson · 10th Mar 2017, 2:33 pm

Gentlemen!

Thanks for your help. I shall recap the unit, as advised, replace anything burnt out, and hopefully will have a unit! I'll repost some pics when I've completed the repair work...

...and also can I just say, as a member of various technical / repair forums on the 'net, you guys have been the most prompt, courteous and helpful.

Best Wishes to you all,

Andy.

60 oldjohn · 10th Mar 2017, 7:34 pm

Hi Andy, once you get your set running ok, I would advise you replace and set up the "Idle Current" skeleton preset resistors. In my experience they are usually way out and may drop in two when attempting to adjust. This applies to most of the B&O amps in the 1980s.

Good luck with it, John.

'LIVEWIRE?' · 10th Mar 2017, 11:12 pm

I usually replace skeleton pre-set pots. with enclosed types such as the Piher range whenever possible.

60 oldjohn · 11th Mar 2017, 12:06 am

IIRC I got mine Piher preset resistors from Maplins.

John.

8th Mar 2017, 1:56 pm	#1
AndyJackson Retired Dormant Member Join Date: Mar 2017 Location: Glasgow, Scotland, UK. Posts: 3	BeoCenter Board 8002495 Good afternoon folks! I have inherited a broken BeoCenter 2002 T2101, and on inspection inside, there is a small board before the speaker amp board (ref. 8002495) that houses what appears to be a relay, and some resistors. Resistors R101, R102, R201 & R202 along with the relay are not there! Puzzling... I have a schematic for the 2000, but there seems to be no info on component values for this small board. Am I blind, and not seeing them? (perhaps - Ha!) If any of you chaps have the component values for these resistors, I'd be most grateful. Also, I have since managed to source a replacement relay... Best Regards, Andy. Attached Thumbnails

8th Mar 2017, 3:36 pm	#2
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,989	Re: BeoCenter Board 8002495 Hi Andy, welcome to the forum. Nice photo, can we have a photo of the other side please. John.

8th Mar 2017, 4:42 pm	#3
Grubhead Heptode Join Date: Dec 2016 Location: Sheffield, South Yorkshire, UK. Posts: 539	Re: BeoCenter Board 8002495 I suspect the board is a speaker protection circuit. It's likely someone removed it thinking it was causing the amp not to work. I would make a close examination of the main amp section as that would be a primary cause of amp failure. The parts were clearly there at one time.

8th Mar 2017, 9:25 pm	#4
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,225	Re: BeoCenter Board 8002495 I would suggest the resistors are part of the headphone circuit. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

9th Mar 2017, 4:01 pm	#5
AndyJackson Retired Dormant Member Join Date: Mar 2017 Location: Glasgow, Scotland, UK. Posts: 3	Re: BeoCenter Board 8002495 Here's a pic of the other side of the board. Check out that scorching! Something went explosively... Best, Andy. Attached Thumbnails

9th Mar 2017, 6:04 pm	#6
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,989	Re: BeoCenter Board 8002495 Hopefully the demise of R101 & R201 have saved the amps from damage, Certainly been overloaded ! John.

9th Mar 2017, 6:49 pm	#7
D_S_J_R Heptode Join Date: Oct 2010 Location: Suffolk Coastal, UK. Posts: 603	Re: BeoCenter Board 8002495 For the first few years at least of their lives, these units were very reliable electrically, the main issues being sticky tonearm lifting (dried grease turned to glue) and ubiquitous neglect of the cassette deck despite often heavy use. They're getting old now so care should be taken to check electrolytic caps as B&O rarely under-used them for longest life (I know these units were far eastern made I believe, but even so...) and many Beomasters of the 70's suffered bulging 'Roe' caps I remember... __________________ Best wishes, Dave

10th Mar 2017, 2:33 pm	#9
AndyJackson Retired Dormant Member Join Date: Mar 2017 Location: Glasgow, Scotland, UK. Posts: 3	Re: BeoCenter Board 8002495 Gentlemen! Thanks for your help. I shall recap the unit, as advised, replace anything burnt out, and hopefully will have a unit! I'll repost some pics when I've completed the repair work... ...and also can I just say, as a member of various technical / repair forums on the 'net, you guys have been the most prompt, courteous and helpful. Best Wishes to you all, Andy.

10th Mar 2017, 7:34 pm	#10
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,989	Re: BeoCenter Board 8002495 Hi Andy, once you get your set running ok, I would advise you replace and set up the "Idle Current" skeleton preset resistors. In my experience they are usually way out and may drop in two when attempting to adjust. This applies to most of the B&O amps in the 1980s. Good luck with it, John.

10th Mar 2017, 11:12 pm	#11
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: BeoCenter Board 8002495 I usually replace skeleton pre-set pots. with enclosed types such as the Piher range whenever possible.

11th Mar 2017, 12:06 am	#12
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,989	Re: BeoCenter Board 8002495 IIRC I got mine Piher preset resistors from Maplins. John.