ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Little bit more about the 5500. I don't know if this is common fault in 5500 series but RCA sockets in this amplifier were lose from the soldering points. I had to solder them back to the board.
It sure looked like no external damage just poor soldering job from beginning. I discovered it when plugin in my phone via tape 2 RCA sockets. Lucky for me that was very easy soldering job and didn't even have to take off the cover.
I just (hopefully) repaired another 6500. This Beomaster worked fine for a couple of hours, but if you then put it into standby, after an hour or two the standby dot would vanish and the Beomaster seemed dead. Leaving it unplugged from mains for some time usually gave another try.
I replaced the usual caps - see the first pages - and it seemed to work fine. I then disconnected it from mains to remove the probes I used for idle current adjustment (I don't do that "my probe slipped and I fried the device" stuff) , but it was dead again when I connected it back to mains. Not even the usual relay click (which actually means the amps are powered on - the Beomaster energizes the main relay when it goes to standby).
Some measuring around revealed missing standby power, just a little over a volt at the emitter of TR12. So no power to the CPU either. Turned out to be an intermittent standby power rectifier (D3). I replaced it and all seems fine again.
I'm posting this because my BM5500 had an intermittent D3 as well when I bought it years ago. Seems like a common fault.
--mika
Does anyone have parts to this card available, (processor, rom )? I have one with no life. Only some curious level pulse between processor and rom data line. Chrystal, voltages etc are ok. Card is identical as yours only S/W is 1.4
The processor is a generic 8032 which should still be available; if not new, then NOS on some popular auction site (avoid the later "downward compatible" derivatives which have additional features, as they may not work properly with the B&O firmware). I guess the ROM could be easily replaced with a regular 27512 EPROM chip, but of course you would need to get the firmware from somewhere. I would be suprised to have a faulty ROM, but the CPU is a bit susceptible to ESD and overvoltage hazards from the external Datalink lines.
But first check carefully the reset circuitry, as the processor won't start up correctly if the RESET signal isn't driven properly when the power comes up. The PSEN and ALE lines should have a lot of clean logic level traffic at ~1 MHz when the CPU is running.
Hello all!
I have decided to replace some capacitors in my BeoMaster 7000 (module 9, the front circuit board with the display) as described in this thread.
I have measure the three of them with my ESR meter and one was dead, one had 5 times the resistance and the third was ok. I will be replacing all three.
Question 1:
The values I read from the components are:C15: 1uF/100v (Question, I cannot find 100v anywhere, only 63v, will this be okay???) When i look at the service manual I am not sure how to read it. Is it mean that the voltage is 40v? Please see picture from service manual I have attached.
C20: 10uF/63v
C19: 2u2/63v
Question 2:
Will I need to tune the IR receiver once I have replaced the capacitors as per this quote or was this due to a more complex issue being investigated?
Look at page 7 from the below service manual, that is where I took the clip from:
BeoMaster 7000 service manual
Many thanks all, I will report once I have completed the repair.
BeoMedia
63V should be enough for C15. It sits on the unregulated 40V power supply line, and the filter cap for that line (in the power supply) is actually specified as 50V. 100V was probably just a convenient choice when the Beomaster was designed.
Don't touch the adjustments (I probably wouldn't have needed to either).
All three capacitors are now replaced and the system started up effortlessly from standby (so far so good). The repair went very easy and I have some pictures I can upload later if there is any interest.
However, trying to start it up from standby at a later time (i.e. after it has been connected to the mains for some time) it is again not very sensitive at all to receive an ir command like RADIO or similar. (I have even disconnected the aerial but it is the same issue.) Once it is turned on it is very sensitive to new ir commands and works as it should. The problem is only when trying to wake it from standby.
Are there other capacitors on a different circuit board I should be looking at as well? Should be likely as they are all equally old.
Any pointers would be much appreciated.
BeoMedia: However, trying to start it up from standby at a later time (i.e. after it has been connected to the mains for some time) it is again not very sensitive at all to receive an ir command like RADIO or similar. (I have even disconnected the aerial but it is the same issue.) Once it is turned on it is very sensitive to new ir commands and works as it should. The problem is only when trying to wake it from standby.
I have the same problem with Beomaster 6500. If I disconnect it from mains and replug it, it will work fine again - for some time. I would also be delighted if someone has clues where to look for...
Hello Mika and all on this thread,
I thought I would need to continue my work on my BeoMaster 7000. The issue I have had for some time now is that the BeoMaster 7000 is not very sensitive at all to an ir command when it is in stand by and has been connected to the mains for some time. (If it has just been connected to mains it is fine. Once it is powered up and playing it is also fine.)I have looked at the capacitors on the power supply and power amp board as per Mika's brilliant tutorial on the first page of this thread and I will be looking at replacing these. I measured them with my ESR meter and all but one gave an acceptable value.
However, I am now also struggling with poor signal reception on the radio. I can hardly get a channel. So, I also looked at the caps Mika mentioned on his post concerning the radio circuit board. Here I also had poor caps according to my ESR.
Then I went on to measure other caps on the same radio circuit board and many of these were also out of spec!
Question: It seems to me that most caps on these systems are ripe for replacement. How should an amateur go about this? Shall I try to replace all caps that measure out of spec or only take one step at the time (for me it would probably be replace the caps on the power circuit board, then later move on to the caps Mika mentioned on the radio board).
Shall I leave the other out of spec caps be for the time being?
In theory it should not hurt to replace them all but I understand that the circuit boards are rather fragile and traces can easily lift from the board.
Question: How do you guys repair a lifted trace? Are there any pens that can carry this sort of current or how do you save your boards once a trace has lifted? What is the best temperature to desolder caps with to avoid lifting traces perhaps 400 celcius?
Many thanks all! I really want my system back to full glory and I will happily be posting pictures and comments from what I have learnt along the way once I am done.
BeoMedia:Question: It seems to me that most caps on these systems are ripe for replacement. How should an amateur go about this? Shall I try to replace all caps that measure out of spec or only take one step at the time (for me it would probably be replace the caps on the power circuit board, then later move on to the caps Mika mentioned on the radio board).
Do the mandatory caps first - these are the small electrolytics in the power supply and the CPU board (maybe the front panel as well). No need to even measure them.
The rest is optional... the tuner problem is probably something else than caps, and it is easy to get back to that later anyway because the board is the first to come off.
BeoMedia:Question: How do you guys repair a lifted trace? Are there any pens that can carry this sort of current or how do you save your boards once a trace has lifted? What is the best temperature to desolder caps with to avoid lifting traces perhaps 400 celcius?
The old soldering alloys that contain lead (and these were definitely used at the factory at that time) melt at about 180°C. Current lead-free solders melt/cure at about 220°C. The right temperature depends on your soldering iron. If it is slow to react to the cooling of the tip of the tip (so to speak) or the tip has poor heat transfer to the object, you may need a bit more to compensate. But 400°C is probably the upper limit, you shouldn't need that much - with a too hot iron, the resin evaporates off the solder making soldering difficult, and you will overheat the components and the PCB.
But don't use too low temp either, because then you will also overheat the components because (de)soldering takes so long. The "usual" tip temperature for lead-free solders is 350°C.
To help save the traces, don't start wiggling the components until the solder has actually melted through. With two-legged upright components such as most caps in this case, try to avoid pushing the opposite leg in while trying to pull the other out through the PCB. If the component is to be replaced anyway, you can cut the legs off first if there's space, and then easily remove them one by one.
And when the accident happens, I usually solder in a jumper wire if the next solder spot is very close (1 cm or so). For longer distances, it may be more sensible to scratch off the insulation on the trace and solder a short wire on top of that.
Just match the capacitance and voltage and you’ll be fine. If you cannot find the exact voltage rating, replace with the next higher value (10V -> 16V and so on).
The T and M are probably tolerance ranges, you can ignore them in these applications.
I was reading this and wanted to mention something a bit similar that I did.
I live in NYC and I bought a BM and a BC6500 from France. I converted them from 220 to 120V (actually on the BM6500, 120 is not an option. They seem to have had separate transformers for the US and Japan of 120 and 100V, respectively. The two coils on the 220/240V models have taps at 110 and 130V only, not 120).
I decided to go with the 130V taps. Now these are normally connected in parallel and in phase, to have the same power at 110/130. But I will not be using the power amp on the BM. Then why waste electricity on a larger trafo? So I only connected one of the two 130V coils to power, leaving the other idle. I should have tried it both ways to see if in fact it draws fewer milliamperes that way in standby but that is a project for another day.
tournedos:...the tuner problem is probably something else than caps, and it is easy to get back to that later anyway because the board is the first to come off.
Hello again, I have replaced caps on the BeoMaster and the IR reception is perfect again. I also replaced the backup battery while I was in there and it turned out it was a little sweaty underneath so timing was good.
However - my radio reception does not work. Occasionally when fiddling around with it I may be able to get one channel with sort of okay-wish signal. Then it disappears and I can't get a channel to tune in again. When I start the radio up and try to tune for a radio station it tros for a very little while and gives up. I only hear static.
When I look in the service manual the advice is to replace the entire radio board. What can I do as this is not possible. I have replaced many of the caps to no avail.
I do not have a lot of equipment other than an ESR reader and multimeter (and obviously soldering iron).
I would really appreciate help in getting this unit up and running again :-)
Thanks and have a great weekend, BeoMedia
Unfortunately I cannot help much with tuner problems. Major repairs to it would need test equipment even I don't have.
I can only suggest that you redo any dubious looking solder points, and perhaps clean the connector socket/plug on the tuner board that receives the aerial cable from the rear panel. Mine was black inside.
Also check that the wiring looms are all connected with no loose wires.
tournedos:The preamp board has plenty of electrolytic caps on the signal paths and they could be replaced with fresh caps or upgraded - if you're interested in that, visit Die Bogener's workshop thread on BM6500/7000 in the archived forum.
Hi Mika,
Thanks for all your tips in this thread, I am new in a B&O world. I just bought beosystem 6500 and using it with beolab 8000. Thanks to your tips I changed power to 240V (which reduced heat at work and an electric smell near the device). Now I am thinking to change capacitors in the pream line, the speakers significantly play more open sound when connected directly to the source than through the preamplifier. The link you pasted does not work at the moment, I hope it could help in the selection of new caps. Do you know where I can find this archive?
olmaster: tournedos:The preamp board has plenty of electrolytic caps on the signal paths and they could be replaced with fresh caps or upgraded - if you're interested in that, visit Die Bogener's workshop thread on BM6500/7000 in the archived forum. The link you pasted does not work at the moment, I hope it could help in the selection of new caps. Do you know where I can find this archive?
The link you pasted does not work at the moment, I hope it could help in the selection of new caps. Do you know where I can find this archive?
Ah, the link needs to be https to work; like so.
Hi Mika and others reading this thread.
Firstly a quick recap of the tuner problem: It plays static noise and occasionally it will randomly catch on to a signal (after been disconnected from mains for some time) that is not super clear. Changing the frequency (the stored channels) does indeed show a new frequency but plays the same as if it has not changed the frequency though the display suggests this. I cannot tune for a strong signal as tuning (auto or manual) does not find a signal.
Since my last post I have now acquired a second BeoMaster 7000 that didn't look as nice cosmetically but worked fine (including the tuner part). I wanted to move tuner card to my initial BM7000 which looked nicer and to which I have changed caps and updated the SW.
I successfully moved the tuner card that I had confirmed was working in the donor BM7000 (which was same part number) to the initial BM7000. In the beginning it worked fine (few moments while I was trying to store some channels) then after say a minute or two it reverted to the same symptoms as I experienced with the old tuner card.
I then tested the donor BM7000 with the old tuner card (which I thought was the problem) and it worked perfectly.
The good news is that the tuner cards (both of them) are perfectly fine which is great as these are very difficult to repair.
The bad news is that I have still not managed to sort out the problem.
What do you think it sounds like the problem is?1) is there a bad cap somewhere suppling stable power to some relevant part which could explain this? (I have replaced the caps at the power supply and behind the display to ensure good two-way communication which solved the previous issue that it would not respond to IR signals and turn on). Doesn't it sound like it is a bad cap as it works well the first time for 1-2 minutes after when I connected it after I had swapped the tuner card but then fails again?
2) Could it be the CPU of the BM? Likely not as it does perform all other tasks?
3) If one of the connectors or wires could you please help direct me to which one it could most likely be? They are all rather brittle and fragile after all these years and I would prefer not to pull in all of them too much. Perhaps it is the electronics near the CPU that are at fault as I guess that is where the instructions to the radio card is coming from and where station presets are stored?
I am really looking forward for some help on this topic as I hope to get them both alive and working again.Many thanks, BeoMedia
tournedos:So, after a quite a while of tinkering, every electrolytic cap in the signal path of the preamp is now either Nichicon audio grade electrolytic (10µ) or Wima MKS2 (smaller values).
Curious where do you order components from or was it ready cap kit or did you make use of the list in the old forum thread Workshop BM6500 BM7000? Also, where would be the best site to order from?
//Kim
Regarding switching from 220V to 240V - I presume you can also do the same for the CD, tape deck and turntable? Any experience with this?
I recently also made the 240V change to my Beomaster 7000. However, it is still warm in standby. I tried hooking it up to one of these power saving sockets, and it does not shut down other devices when put in standby, so I guess it draws the same current whether in standby or not. I did a few measurements, and I suspect that TR19 is faulty as it lets current flow both ways, which I am pretty certain it shouldn't. Any other guesses?
Cracked solder joints at the amplifier power relay.Or a bad relay.
Martin
wow - so simple - it was indeed a cracked solder joint. I had inspected it but it looked okay but apparently it wasn't. It works now as it should. Thanks, Martin
Here is a picture of the part - if you look closely you can see the cracked solder.
Good!
Now on to your magnifying glass and inspect the rest.
Jacques