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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
I picked up a Beocenter 9300 that was for sale locally back in June. The CD player didn't work and the glass panels were loose (they were missing all of the trim pieces except for the two that bolt to the frame).
After adjusting the CD player and finding some replacement panel trim pieces I have the unit working again. The only problem is the remote control doesn't work. I have two Beolink 1000 remotes that work fine with my Beomaster 5500. Nothing happens when I try them with the BC 9300 though.
I pulled the remote control receiver board but I'm not sure if I should open it up any further. The connections look fine. Where is the best place to start on this type of problem?
-sonavor
I presume that you have checked it is not set to Audio Option 0, whereupon it will not respond to a remote?
On a Beolink 1000 press STBY, SOUND, 1, STORE
Does the 9300 work with the remote work now???
Regards Graham
I tried that with each remote but no response from the Beocenter. Beoworld doesn't have a service manual for the Beocenter 9300 specifically. There are service manuals for the Beocenter 9000 and 9500. I have an original service manual for the 9500 which shows how to put the Beocenter into a test function mode. I wonder if the 9300 also has that feature? I'll remove the bottom glass and check.
After going through the Beocenter 9000 and 9500 service manuals I see that the 9300 IR board is different. So far I haven't had any luck tracking down a Beocenter 9300 service manual. I found a reprint of one for sale on Ebay from the UK but the shipping seems a little steep. I can go ahead and use the Beocenter as it is (without the remote).
What is that black discolouration by the silver capacitor? Is it leaking?
cozza: What is that black discolouration by the silver capacitor? Is it leaking?
The black marking on the side of the 22uF silver capacitor is a polarity marking (black is the negative side). The base of that capacitor is a black plastic material. It is a surface mount capacitor. Beoworld member Menahem already suggested replacing that cap with a new one. As I don't have a service manual for the BC 9300 yet I decided to go ahead and replace that capacitor. Unfortunately, it didn't fix the problem. I didn't have a surface mount capacitor and the smallest I had is as pictured here. I should receive a photo copy of the BC 9300 manual in about a week.
Correction - On my posting of the replaced 22uF capacitor I think I see what your question was about. You are referring to the series of black spots between the 22uF capacitor and the SMD resistor. Yes, I was wondering about that too. Is that just discoloration from the manufacturing of the board or is it just age? Or is it a symptom of a problem there. Replacing the 22uF capacitor didn't fix the problem though and the trace side of the board doesn't show anything unusual.
I finally received a copy of a Beocenter 9300 service manual. The copy isn't too bad. Some of the images of the circuit boards could be better but it looks usable.
As it turns out, the Beocenter 9300 internal test mode doesn't test the IR section as the BC9500 does. The service manual does show the IR circuit board and shows what the what the board connections are. I will check power on the board (5V) and see what else I can measure.
I don't know if this is a valid test but here is what I tried today.
I pulled the IR Receiver PCB out of the BC9300. According to the service manual, the three pins on the single, board connector are P49-1 : +5 VDCP49-2 : SignalP49-3 : GNDSo I connected my +5 VDC power supply to P49-1 and 3 and my scope probe to P49-2. Occasionally I saw some pulses on the P49-2 line but mostly it was quiet. I didn't see any activity on the scope when I pressed buttons on the remote control. With power on the IR board, should I be able see signal activity on P49-2 when I press buttons on the remote control? Since I didn't, it seems like the board is dead.
I have a question about refurbishing the glass panels on the Beocenter 9300. There are a few places where the black coating on the back of the panel (where the old glue/tape was) has rubbed off. It is noticeable when the glass is mounting in the trim so I would like to fix that. My local art supply store suggested I clean the back of the glass and paint it with 1 Shot Sign Painter's Enamel Paint. It sticks to glass and has excellent coverage. I think it only comes in gloss enamel though. Has anyone successfully fixed these Beocenter panels? I am planning on masking off the display areas so no paint gets on the colored film strips.
sonavor:With power on the IR board, should I be able see signal activity on P49-2 when I press buttons on the remote control?
I haven't seen the schematics of that board, but I can only presume it contains the entire front end - demodulator combination (where does the signal line go in the other end? Directly to a processor pin?), and you should see clean digital level pulses on the signal line. So it seems that it indeed does not work.
As to your panel question, I have simply used a black felt pen on the scrubbed off areas, and can tell diddly squat of a difference to original paint once the panel is installed. If you have larger damaged areas (not just scratches), it might be worth trying a proper paint.
--mika
Here is a scan (of a copy) of the Beocenter 9300 IR Receiver.
sonavor: Here is a scan (of a copy) of the Beocenter 9300 IR Receiver.
Seems like it definitely should be a clean digital 5Vp-p signal at the output. Try scoping pin 7 of that (which?) IC. If you don't see a clear correspondence to the remote signal there, it might be difficult to repair unless it's simply a dead photodiode. If you do, you have a problem around those two output transistors.
Obviously check internal supply voltages and those few caps.
Looks like you've already changed C8 on PCB2 but there seems to be another of those dreadful leaky Panasonic SMD caps in the silver box.
That one (C9) is smoothing Vref and could well be the reason for not receiving IR.
I think the Beolink7000 has a similar circuit and that is known for missing 2-way-IR-reception with the 22uF Pana's leaking
Don't know how to open the box, I suppose it's soldered to the board like usual.
You will smell if the cap has been leaking while desoldering it - a smell you'll never forget again
Good luck,
Gunther
EDIT: looking at your pictures the metal cover IS soldered to the PCB...
@ tournedos - according to the SM the chip is a U2506B...
hemenex: Looks like you've already changed C8 on PCB2 but there seems to be another of those dreadful leaky Panasonic SMD caps in the silver box. That one (C9) is smoothing Vref and could well be the reason for not receiving IR.
Indeed... a typical 455 kHz B&O IR receiver is actually very close to being an AM radio receiver, both functionally and from circuit design viewpoint. It doesn't need much interference to not work properly.
I opened the shielding box. You are right, there is another electrolytic cap inside. I think I will go ahead and change it but I will have to order a smaller size replacement than the standard one I used to replace the cap outside the shield box.
I replaced the other SMD, 22uF capacitor on the IR board but that did not bring the board to life. I double checked the signal again. With power (+5 VDC) applied the board output signal (P49-2) goes up to +5 VDC and stays there. Using the remote control I cannot catch any activity on that line.
You may be "chasing your tail " here somewhat sir?
It's very common for the ir diode to become noisy with age,this will obviously affect the remote control function.
They are readily available,the type No is on the body of the device.I've also used a replacement type available from Maplin Electronics in the UK,or online.
Surface mount electrolytics are also available as direct replacements to fit inside the can etc.
Regards,
Nick
I will try that next then. My replacement components so far were from recommendations of other forum members. The capacitors I replaced were also the easiest for me to try first.
Thanks,-sonavor
It is a good idea to take a cotton swab dipped in isopropyl alcohol and clean the board thoroughly. Those leaky caps usually leave electrolyte on the board which will be a problem. Don't be afraid to get the board really wet, and focus on the the IC itself, you want to dilute and flush away any residue. I see a couple of the pins look a little green on the U2506 which is typical corrosion from leaked electrolyte.
Thanks, I will try that.
Is the IR decoding on these boards proprietary to B&O or is the IR decoding something common? Can another IR receiver (that uses +5VDC for power) be used as a replacement?
The receiver does not do any decoding of the data per se. It demodulates the signal removing the 455kHz carrier and sends the received data out the output pin, just like the integrated receiver packages do. The IR is also filtered and processed by an automatic gain system before demodulation.
Another receiver chip could be substituted, however the discrete design used by B&O used has very high sensitivity and you will find a TSOP style receiver is very directional if used as a replacement. This means you'll have to aim the remote at the beocenter more.
If you persevere you should be able to fix the receiver. The IC is used in other B&O equipment, so if you have a scrap beolink 5000 or a beaten up link eye (ML) lying around there is a spare in that. It is very unlikely to be the IC at fault, but not impossible. The filter circuitry around the IC is fairly high impedance and would be impaired by leaked electrolyte.
In the past I've found beolink 5000s with poor or no IR receive have had leaky caps around the U2506B receiver, and cleaning the board and replacing the caps fixed the problem, same with the beolink 7000.
The decoded data pulses are pretty short, so make sure you have your scope set to an appropriate timebase when fault finding.
Definitely try a replacement photodiode if recap and cleaning does not fix the problem, however make sure that it is a close or identical replacement. The capacitance of the photo diode affect the tuning of the IR front end filtering.
The BC9300 service manual says it is a B&O part (8330145) - IR Detector 455kHz. That same part is used in the Beosound MK-III where it is described as an IR Detector, 880nm, 455kHz. The back of the device says TEK BPW82 which appears to be a Vishay photodiode. Mouser has it in stock so I will pick one up before the weekend.
I picked up my replacement photo diode (Vishay BPW82, 60V, 215mW, 650nm) today and I am happy to report that did the trick. My Beocenter 9300 remote control functionality works. Thanks for the help in debugging that.
The next step for this project is cosmetic. The unit came with detached glass panels that I had to reinstall into the plastic trim. When I first re-installed it I checked the glass borders and didn't see any light pass through. However, after I glued the pieces in (Aleene's Tacky Glue), various places along the glass border looked like they had bubbles. I was able to easily remove the panels from the trim and get rid of the glue. The glass is missing some black paint from around the edges in a lot of places now. I have two ideas to repaint it black. One is to mask off the areas that need light to go through and spray paint the back with a flat black. The other is to paint the back with a brush using 1Shot Sign Painters' Lettering Enamel (199-L Lettering Black). I guess the best thing to do is take some blank piece of glass and test how well each paint works after painting, drying and test gluing a piece of plastic to it.
My success was short lived. After I re-installed the IR board into its normal position it stopped working. I removed it again, took off the metal shield box and it started working again. But only for about a minute. I was able to operate the radio and volume control, then it went dead again. I am afraid that there are other components (SMD components) that might also be bad. So I am back without remote control capability on this Beocenter. I have to decide if I want to take on trying to replace the IC and/or transistors. I will probably wait for a spare to come up for sale.
Update on this Beocenter 9300.
After repairing the DC power for the processor on a friend's Beocenter 9500 I started looking at my Beocenter 9300 again. With the 9300 cover open yesterday, the remote control functionality started working again. It continues to work today. So I am thinking this problem must be a wiring or connector problem. An odd problem for sure these apparent connectivity issues.
I think I am over the hump with the Beocenter remote control problem. I never had a problem with the remote control functionality while it started working with the BC9300 cover open. I left it like that for a couple of days and tried the remote several times during that period. It always worked. When I closed the Beocenter up, the remote stopped so it had to be with the connecting cable. I thought about building a new one with new connectors but I decided to remove and resolder the connector on the P2 IR Board. That did the trick. I have the Beocenter all put back together and the remote is working properly. How many times does a problem end up being caused by a bad connection or a wiring problem?
This unit is in getting in pretty good shape. The radio and CD work good. The auto-reverse cassette deck works okay but I think it needs some maintenance before I can declare it fully functional.