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B&O Beomaster 2400 (type 2902) touch panel unresponsive

PCMALO

PCMALO

Member
Greetings! I just picked up a very nice Beomaster 2400 that had a few problems - some burned out indicator lamps, noisy balance control, dead phono section - but otherwise worked well and sounds fine. So I took it apart and replaced the lamps and cleaned the balance control contacts. But when I put it back together, the touch controls were not all working. So I removed the control panel and manually touched the pins that the copper fingers on the touch panel normally touch to activate the control. All the switches worked fine when I did that. So I replaced the control panel, making sure the copper fingers engaged with the pins on the PC boards, thinking that was the original problem. However, now the #4 tuner switch lit up but wouldn't switch off and none of the other switches would work.

So I took the control panel off again and tried touching the pins with just my finger again. That had worked earlier but now would NOT work! Huh? Initially I could hear the switching relay chatter a bit as it tried to switch inputs but now nothing. The volume up/down touch controls work fine but not the input switching switches nor the standby switch.

Has anyone else had this experience and determined the problem? I had high hopes for this unit to be my turntable repair testbench control center, especially since it can be hung on the wall! Of course, that all depends on if I can eventually get the phono section working...

Any and all ideas and suggestions welcomed!
 

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The last time I had this type of issue with a 2400 (volume pads inoperative) it was one of the IC's in the switching circuit. Can't recall the details, it was a long time ago.
 
Doing a bit more online research, I came across someone with a similar problem that he resolved by replacing the TR27 transistor on board 2 (2TR27 - 8320257-TIP 32 A). If I de-solder it to test, what values should I be looking for at the E, C and B terminals? And if I don't de-solder it, are there values I should find if the receiver is turned on as well as when it's turned off? I can find a replacement in Denmark that costs less than $5 but about $20 to ship! So I'd love to know whether it's defective or not before just replacing it.

Many thanks!
 
You can get a TIP32AG from Mouser in the US for $1.36 but shipping will be about 5 times that.
 
Thanks for the info, nerdorama. I ordered two of them for a total (with shipping and tax) of $11.46. Fingers crossed! :thumbsup:
 
Well, replacing TR27 didn't help. In the meantime, I found another Beomaster 2400 v.2902 on eBay that seems to work better except it is stuck on tuner FM3, not FM4! If I press any other input, that input will connect but as soon as I lift my finger off, tuner FM3 will latch on again.

I removed 2TR19 since a friend looked at the schematic and said that transistor played a part in the switching and thought removing it would unlatch the input. But it did not. FM3 stays latched on.

If anyone has had a similar situation and found a solution, I would be most grateful! I have the service manual but it is over 4MB and too large to attach. But it is available at https://www.hifiengine.com/manual_library/bang-and-olufsen/beomaster-2400.shtml, if you are curious. :)

Many thanks! Pat
 
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