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Hi everyone,
i have a Beocenter 9500 which is in perfect condition.. Except for the numerical display on the upper right hand side of the unit which does not work. (This is the display which shows radio frequency etc)
Any pointers on where I should begin looking/what the problem could be? There is no sign of life from any of the four digits.
Thanks in advance,
Steve
Hello and welcome to Beoworld!
I have had a BC9500 for several years and follow most threads about it, but have not heard of that problem before. Last time I serviced my BC, I took a few photos, hence I have one of the problem area. The four digit display is a discrete PCB (no 46), hence if the problem is just that display, then perhaps there is simply a loose power connection. You may wish to become a silver member so that you can download the service manual.
Here's a picture of the display with the BeoCenter in service position: (click the picture to get it fullscreen)
Hi Guy
Thanks for coming back to me on this. I am struggling to remove the small pcb from the bigger board - I do have the service manual, however I'm no electrical engineer so reading the diagrams proved difficult!
The top glass is loose, so I managed to come in from the top without opening the entire unit. I did did wiggle the board around and press it in, but to no avail. Do you happen to know where power enters this board, or where I should be looking?
Given that on the circuit diagrams there are a total of 8 connections between board 45 and board 46, I would say that the power comes through the 8 way connector on the right hand side! If you have a multimeter, try between the top and bottom pins - you should see 5v.
Just took the top panel off mine to check. At stand-by (when the board still gets power in order to produce the little red stand-by dot) I get 4.6V between the top and bottom pins of the 8 way connector. The bottom pin is +ve.
I will leave the top panel off for now in case you need me to check anything else!
Thanks Guy. I don't have a tester with me - so it will have to wait until next week. Sorry about that. I'll give you an update as soon as I get the readings - it's strange that this is the only fault part on the unit. I do hope it's not a sign of a massive underlying issue that involves bigger overhaul... :(
No problem - to be honest if everything else in the top display is working fine then hopefully it's quite a minor fix or replacement.
Thanks guy - I really appreciate all your help thus far. I'll let you know re voltage as soon as possible
Hi guy
good news - I get 4.65v when measured across those two pins. Both in stand by and when switched on.
That's good - hopefully then the fault is local to PCB 46.
A thought, it would be worth running the LED test procedure that is at page 7-6 of the manual. You can see the two pins that you have to short together in the bottom right of my photo (labelled TEST MODE). Short then pins, then pressing 'CALL' should then make the top right LEDs, and display, light up.
Thanks Guy. Can I access this without opening the entire unit - ie just removing control panel glass from the outside? I'm concerned that the panels are loose and may fall out. Re the CALL button.. Where do I find this?
Yes you can access just by removing the lower glass panel. It's in the manual, but simply undo the single phillips screw just under the bottom left edge of the unit. The lower glass and its plastic frame then slides to the right a few mm, and will then lift up. Be careful with the glass!
And the CALL button is above the number 5 on the bottom touch panel. It only lights up when you need it in normal use, but I think it will light up after shorting the TEST MODE pins. You can simply touch your finger lightly on the exposed CALL sensor - it is labelled on the lower PCB.
Nevermind - I managed! Did the test and got this:
I managed and got this:
This display is cooked!!
Am running out of ideas. Unless anyone else on the forum has a better idea, and given that PCB46 is possibly 'fried', you could try making a very small adjustment of the variable resistor R2 that is visible in your picture. According to the manual, the adjusts the PCB46 light intensity. It should be adjusted with a 100 ohm resistor across pins 20 and 18 of the IC, looking for 0.7V after pressing CALL in Test Mode.
Alternatively, start searching eBay for spares - probably PCB45/46 together. BC9500s are often being broken for spares. The PCBs in a BC9000 look similar but I note a slightly different part number for PCB46 - an A instead of B at the end.
See here: http://www.ebay.co.uk/itm/Bang-Olufsen-Beocenter-9000-OEM-Display-And-Notification-Top-Panel-/171817953784?hash=item280125e9f8:g:M5MAAOSwNSxVc32F
But it's a bit pricey!
Perhaps someone else on the forum has advice???
Appreciate all the help Guy. I did see the 9000 PCBs on eBay, However as you say, the part no and chip numbers differ. I'll keep an eye out for something.
is it possible to remove PCB 46 from PCB 45 by hand, or is it soldered on from the back? I tried but struggled and didn't want to snap PCB 45 in the process. Ideally if I buy 45 + 46, I'd like to remove 46 and put it onto the existing board.
I have never tried removing PCB45 or 46, but if you disconnect all the connectors it looks like just two screws to remove both PCBs - then you should be able to see how the two are joined.
Before doing that, it's worth checking (unplugging and reconnecting) the two cables between these boards and the main PCB. It's possible a loose connection there could be the problem.
EDIT: From the circuit diagram, one of the data feeds is going exclusively to PCB 46, so perhaps the data is just not getting through to initiate the display.
EDIT 2: Are the FM, AM or STEREO lights working? Although they are on PCB45, they are controlled by the IC on PCB46.
The AM. FM and Stereo lights are fully functional. I'll try disconnect and reconnect - hopefully that solves the problem?
Of course your photo showed the STEREO light working. Assuming that even in TEST MODE it is controlled by the IC,, then perhaps the IC is functional.
In this case, the only components that supply just the 5 digit display are the two diodes (D2 and D3) - one or both could be faulty: Both are 1N4002s which should be readily available. Could be worth removing the boards and replacing the diodes - if you can get at the back to solder. Perhaps ask someone qualified to replace?
I struggled to remove the bigger white plug. It's just too tight. I did remove the 4 pin brown connector and reconnect. Nothing unfortunately.
What is the likelihood that the diodes are the issue? It seems the only logical explanation?
Maybe check the voltage at the lower (white stripe) side of D2 - this should be supplying constant voltage (approx. 5V) to the digit displays.
(Excuse my ignorance -how would I do that with the multimeter - where would I touch the two pins from multimeter)
OK, touch the negative probe to the top pin of the 8-way connector - I think we established that was ground yesterday.
Then touch the +ve probe to each side of each diode in turn: D3 then D2. I think by design you should see an equal voltage drop across each, with something less than 5V at the lower end of D2.
D2: 4.13 (top), 1.06 (bottom)
D3: 4.13 (top), 4.67 (bottom)
(The lower end of D2 seems to drop to 0.00 then back up to 0.6 then up to 1.06.. Fluctuating occasionally)
Great - that all makes perfect sense and I reckon D2 is faulty - the Voltage drop across it is too great to supply the display with power. (The display needs more than the 1.06V that it is getting)
If you know someone who's good with a soldering iron, it's time to engage their help! If unable to get access to the base of PCB46, it may be possible (with care) to cut out the faulty diode and resolder a new one from above.
The diode's a '1N4002' and should be cheap and easy to get hold of!
Guy, you have been an enormous help. I cannot thank you enough for all your time and patience. Holding thumbs that this is indeed the issue. I'm going to track down someone... Or dare I even give it a bash myself. I have soldered before (any tips - esp soldering near a controller chip?)
No problem at all - a pleasure to help. And I just opened my BC again to check voltages - I have 3,3V at the output of D2. Other voltages similar.
Just use a soldering iron with a fine tip, and keep the temperature and contact time to the minimum required to melt the solder. There's plenty of advice on the net, but practise with a few bits of wire first.
Good luck and keep us informed of progress!
Thank you! Final final question - these tight connector plugs on PCBs. Any tips on how remove them without causing damage?
Sorry - I have often had the same problem! They all seems to be different, and very stubborn! Try various tools, including those used for opening mobile phones. Guitar plectrums sometimes help, prised into small gaps and twisted!
In the case of this PCB46 I may try a top solder. I'm too afraid of cracking the PCB below it.
A good decision - I'd do the same!
Guy, great news - you were right. I replaced the diode and she's working again!
Thanks again mate. Hopefully someone else with the same issue with find the solution in this thread
Excellent news indeed! And many thanks for letting me know - it's always useful to know what may go wrong with mine in the future!
No problem - I hope you never have this issue though!! That diode is so very tricky.
On on to the next challenge - A NO CONTACT Beolink 7000.. And a 5000 with the same problem!!