Beocenter 1 with Suspicious Display and IR Board (PCB58)

[Narles]

Hi all. I am new to the community. I have a Beocenter 1 that I absolutely love but it suddenly stopped powering on from standby recently. I am highly suspicious that the problem actually has to do with the IR sensor board and not any kind of power issue for the tube. I believe this TV can only be operated via IR remote so I want to make 100% sure that the IR system is working properly before I start to look at other components for the culprit. I actually got the set to power on last night when I was fiddling with the IR board (identified as PCB58) but I can’t seem to reproduce how I got it to power up from standby. The little metal shield at the bottom with three holes in my picture is the IR receiver. I tested the resistor in the top left and it seems to be good. I also tested with a different 16-pin ribbon cable and that doesn’t appear to be the problem either.
Does anyone have any ideas for how to troubleshoot or test this PCB for functionality? I can’t seem to find a replacement PCB58 for sale. I have some electronics/soldering/repair experience but have no idea where to even begin with this one.

Thank you!

[Madskp]

There are other B&O products where IR issues are related to bad electrolytic capacitors. In most cases it is capacitors near the IR receiver, so they might be within the metal shield.

Other than that have you tried to reapply options settings to ensure that it somehow hasn’t gone to option 0(no ir)

Location: Denmark

[Narles]

Thank you so much for responding and telling me about this. I had thought about removing the metal shield but I will go ahead and do that (after I try checking that it hasn’t somehow switched to option 0). If it is the capacitors under the shield, I am guessing those would be surface mounted components since the back of the PCB has no through-holes in that section?

Thanks again. This is my only B&O product so it really helps to hear from someone with more experience. I tried getting help from the CRT TV enthusiast community but it seems that B&O TVs are such a different kind of product that the regular CRT TV enthusiast community can’t really offer much help for issues like this. Thanks again!

[Madskp]

You are very welcome.

Unfortunately B&O at one point stopped showing schematics in the servicemanuals because the began replacing boards instead of repairing them.  Therefor it can be hard to figure out which components are in the products without disassembly and measuring.

Narles wrote:

If it is the capacitors under the shield, I am guessing those would be surface mounted components since the back of the PCB has no through-holes in that section?

That is very likely.

Narles wrote:

Thanks again. This is my only B&O product so it really helps to hear from someone with more experience. I tried getting help from the CRT TV enthusiast community but it seems that B&O TVs are such a different kind of product that the regular CRT TV enthusiast community can’t really offer much help for issues like this. Thanks again!

Not much experience with repairs on them. I have had B&O CRT’s some 15-20 years ago, but never had to repair them when I had them.

Not much activity about CRT’s here on Beoworld either. Only once in a while. I guess most people that use CRT TV’s today are retro gaming entusiasts. You might be lucky to find something on the archived forums thought.

Location: Denmark

[Narles]

The shield is actually really difficult to remove but, instead, I used some tiny probes and my multimeter to probe the IR RX pin on the ribbon cable connector on PCB58. It reads 5V when idle and then when I use my Beo4 remote to issue the “Go” command, it quickly drops to 4.6V. I’m guessing that means the IR sensor actually is working and maybe the fault is higher up the chain. The search continues. Any other advice from anyone would be greatly appreciated.

[Narles]

Just to close the loop on this, it appears the problem was with a melting adhesive that is used on the inside of the TV. There is a parchment paper that separates one of the PCBs from shorting on the metal DVD player. This piece of paper is fixed to the PCB with a double sided adhesive tape. This tape had become very gummy, almost like a liquid and had turned a nasty shade of brown. I cleaned all of this adhesive off with isopropyl alcohol, removed as much as possible, then attached a new piece of paper to the inside of the PCB with some new double sided tape made for electronics. The TV now works. Thanks to everyone who read this and provided assistance!

[Guy]

Thanks for letting us know the solution – and well done for finding the problem!  Great news that your TV now works 😀

Location: Warwickshire, UK
My B&O Icons:

[Madskp]

Yes very good to know what the issue was. Thanks for getting back as that can be usefull for the next person having this issue 🙂

One more of these detoriation of materials issues to the list of rubber belts, speaker foam and what have you.

This kind of issue can not be predicted by anyone even if they had both the servicemanual and the schematics of the TV set.

 

Location: Denmark

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