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
Hi BEOWORLD,
this is my first post, so i would like to say hello to everybody here.
I am also new to the B&O stuff.
Currently i own BEO DVD 1 and a BEOMASTER 6500.
The last one doesn´t start up. I bought it cheap on ebay and the seller, told me it worked before shipping ;-)
First i heard the relay clicking, no leds on, nothing else.
Now it seems, he does even less.
I opened the silver box, to check the 1A fuse (honestly don´t know how, because on the back it seems that its circuited - a cable is welded from one pole to the other). The fuse itself looks good). All other fuses are o.k.
But i found an exploded capacitor (see picture) i think it s a 47mikroF/10V.
And i checked the Diode D12 (it´s open in both directions - shows voltage 0,5V and 2,5) .
Can i measure diodes, when they are still on board?
Any idea, how get forward with this materpiece?
Very best regards from Germany and merry christmas to You all over the world
69er
Hi, also erstmal ist es nicht normal das die Sicherung gebrückt ist.
das hat der Vorbesitzer wohl gemacht weil sie defekt war, ist.
das sollte rückgängig gemacht werden.
was denn Elko betrifft gehört er natürlich getauscht. Und Dioden wie auch Elkos oder andere Bauteile kannst du in eingelöteten Zustand nicht messen.
es reicht aber wenn du ein Beinchen auflötest um Elkos und Dioden zu messen.
warum nun dein Beomaster nicht geht kann mehrere Ursachen haben. Ist denn die Sicherung auf dem Netzteil noch intakt? Liefert das Netzteil die richtige Spannung?
mach mal ein Bild vom gesamten Beomaster in geöffnetem Zustand
Hallo Schletti82,
vielen Dank für die prompte Antwort.
Ja, das sieht wirklich danach aus, dass jemand die Sicherung überbrückt hat - wie verrückt ist das denn?
Siehe Bild oben. Ansonsten ein paar Bilder, welche ich gestern gemacht hatte.
Von was genau soll ich noch Bilder machen? Oder wo sollte ich messen? Erkennt man denn an einer Diode, dass sie kaputt ist?
Die Sicherungen auf dem Netzteil (die zwei Glassicherungen) sind intakt.
Wo kann ich die Spannungen des Netteils abgreifen (sitze jetzt vor dem Rechner und der Beo ist im Keller - wahrscheinlich finde ich die Punkte).
Viele Grüße und schönes Fest
Frage in die Runde: Die Sicherung und den Kondensator habe ich jetzt bestellt.
Der Austausch der Sicherung wird nicht viel ändern, da er ja eh kurzgeschlossen war.
Reicht das Einlöten eines neuen Kondensators?
Muss ich sonst noch auf etwas achten?
Viele Grüße
Hi 69er
Here's some ideas gained from recent overhaul of my Beomaster 5500 and a similar issue on a Beomaster 5000
No display / no or random microprocessor activity was caused by a failed capacitor responsible for STARTUP RESET. On the Beomaster 5500 and 6500, this is a 33uf capacitor designated C10 on microprocessor PCB 4 (4C10)
On both of the machines I worked on, significant degradation of 5V standby components had occurred, especially the capacitors. I also found an exploded capacitor near the microprocessor on the BM 5000, along with a cooked PCB near the standby bridge rectifier on PCB 2. The large 4700uf capacitor (2C15) is likely to have survived OK, but the small 10uf capacitors (2C14, etc) near the voltage regulators are more likely to have weakened.
Also, any Radial type black capacitors marked "ROE" (for Roederstein) are likely to be failing and should be replaced.
You may have noticed the giant coin cell battery near the microprocessor. This will probably still be putting out 3.2v and merely holds presets in the static RAM. I would leave it alone if reads at or over 3v.
What type or brand of capacitors to use? There is much debate and disagreement on this topic, with many insisting upon using only 105C caps or Film caps where possible, but I have noticed that Bang & Olufsen tended to use "Low Leakage" caps in many places, so my go-to caps are usually Nichicon UKL for low-leakage types, (orange Elna or Rubycon, many ROE caps) or Nichicon UVR for other 85C rated caps. A 105C (221F!) capacitor should only be replaced with a new 105C, of course.
It is OK to replace the Axial lead caps near the microprocessor with easy to find Radial lead ones so long as the ratings are the same and you avoid shorting the leads.
One checks the 5V standby voltage at connector 2P14, pin 2 (edit: pin 5) (on PCB2) to ground. it should read about 5.1v. Pin 1 is nearest the back of the unit.
When you get the microprocessor active, it is important to check the idle current on both channels. It should read 11mv across the emitter resistors at 0 volume with no speakers connected, but this is getting ahead of fixing the immediate problem....
Good luck!
¡No entiendo Español!
NEIN! Nicht Versteh!
Я немного говорю по-русскии но не очень хорошо... и
I'm not very good at English either! Maybe someday I'll find a language I'm good at?
Hi Keri,
i replaced the exploded capacitor and found a broken circuit on pcb 2.
now I have the click on both relays.
but nothing more.
the voltage on p14 is 3,754V.
so no 5,1v
where to look next?
thanx in advance
i replaced the broken capacitor and found a broken circuit which i soldered.
on p14 I only have 3.754V AC
the main power shows 31,9 and 6,16 V AC
what to do next?
3v AC? Uh Oh!
connecter P14 pin 5 (oops, not 2) should have something like 5.1V DC on it.
My main computer with pictures on it doesn't upload to this forum very well.... let me see if I can put up the schematic.
There! Schaltplan!
If you are getting significant AC on P14 pins 1,3 or 5 you've got trouble! Should be around 5.1V DC.
So, new measures.
on pin 1,3 and 5 there are 4,25V DC
seems not to be enough, correct?
hopefully it’s just a capacitor or resistor.
thanx for any additional help.
maybe we’ll fix it this year 😎
Happy new year B&O Fans
Any additional help?
best regards
Any luck on getting the 5.1v fixed? The schematic in my preceding post shows some related voltages to check. It is unlikely to work correctly with only 4.25V, though something might operate, or operate erratically...
Also, it's possible that something is dragging the 5.1v down to 4.25v somewhere else, like maybe the processor board. Speaking of which, did you check both electrolytics? The startup capacitor 4C10 doesn't have to explode in order to fail.
The Main relay will normally pull in and click when the system is plugged in. It is energized so as to turn the main power to the amplifier OFF, not on. As the relay coil circuit is active when the system is OFF, this could also drag down the auxiliary voltage, it should be around 12v before transistor TR12 and 8v after.
No, unfortunately no grogress - i am not the expert in reading ciscuits :-(
When you say, did you check both electrolytics, which one do you mean?
No, unfortunately no progress - i am not the expert in reading ciscuits :-(
On the microproccesor board, Board 4, inside of the metal can are two electrolytics.
One appears to have a tendency to explode, capacitor 4C1. The one that didn't explode is a 33uf axial designated 4C10, 4C10 is responsible for "startup reset", without which the CPU won't start. It is located right next to 4IC3, and on the systems I have worked on they have all degraded seriously without exploding or showing any visible degradation. In particular, on my system that would not start, 4C10 measured a few Picofarads, which is very far from the rated 33 Microfarads, and this was preventing the CPU from starting.
So I highly recommend removing and testing 4C10.
But you also have pretty low standby voltage. at 4.3v, when it should be at 5.1v.
On Board 2, connector P14 terminal 2 should measure around 12v and terminal 4 about 8v. Terminals !,3 and 5 should be at 5.1v, all referenced to chassis ground on P14, terminal 9.
Looking at the pictures, Keri seems to have already swapped out 4C1 (the backside of the PCB shows the position as empty), which presumably was the exploded one. So maybe a good idea to swap out 4C10 too ?
Beogram TX, Beovox S45, Beovox MC 120.2, BeoSound 1, CX50, Beovox S75, Beomaster 2400, Beomaster 5000, Beogram 5005
i exchanged
the 4c10
The 1A fuse
voltages on p-14
1 : 4,18v dc
2: 8,85 V dc
3: 4,18v dc
4: 6,12v dc
5: 4,18v dc
i lost 2-4v somewhere.
the only thing working is the relay, which opens on power.
I just checked the two big 10000yF capacitors with my new MESR-100.
both seem to be not good (even if the capacity seems ok).
rhey show 3,97 ohm and 4,11ohm.
should I replace them?
I would hold off on the two big caps for now, they are not used during Standby.
You say the relay opens upon attaching power to the unit. This is the normal Standby state of the relay 2RL1. The microprocessor system must de-energize this relay to turn the system ON. At this point, the two large 10,000uf capacitors come into play.
In particular, p-14 pins 1,2,3,4,5 and 9 seem most relevant to Standby.
You say pin p-14-4 is at 18v. I believe it should be at 8v.
You did not say what p-14-2 is at. It should be around 13v according to the schematic, I could check on my system later.
You said that p-14-6 is at 12v. According to the schematic, it should be around 40v. This comes from the main power winding of the transformer, tthrough a 15 ohm Fusible resistor 2R18, rectified by diode 2D10 and filtered by capacitor 2C10. As resistor 2R18 is designed to blow open like a fuse, it is a likely failure point for this circuit.
This apparently powers the infrared remote control on display board 9, so I'm not sure how much it would affect Standby. Of course, something like this "could" drag down voltage from elsewhere, like maybe the 5v Standby. If 2R18 is indeed open-circuited, the most likely cause is a short circuit in capacitors 9C15 or 9C20 on display board 9.
I would first check resistor 2R18. It should read 15 ohms or possibly less if in circuit but not more.
If 2R18 is found to be "open" it must be replaced with a similar 15 ohm Fusible resistor. If it is replaced with a regular 15 ohm resistor, causing damage elsewhere is more likely.
You might also try unplugging connector P11 on display board 9 to see if this has an effect on Standby voltage. If I am right, about 5.1v Standby voltage being dragged down, I would start here.
Also, What is voltage on 2P14-2 and 2P14-4? 18V seems wrong for 2P14-4 2P14-9 should be 0v.
i think you read my measurement wrongly or i did not make it clear.
On P-14 i have following voltages
P-14-1 : 4,18v dc
P-14-2: 8,85 V dc
P-14-3: 4,18v dc
P-14-4: 6,12v dc
P-14-5: 4,18v dc
I will check everything else you wrote - thank you very much for your help!
Best regards
I know more:
2r18 has 22ohm
when disconnected the display 11
p14-1 4,97v
p14-2 13,11v
p14-3. 4,97v
p14-4. 8,2v
p-14-5. 4,97v
p14-6. 0v
p14-7. 2,47v
p-14-8. 4,9v
p-14-9. 0v
69ee
P14-6 is 43v
9c20 is short circuited and 9c15 has 25ohm (measured with mesr 100)
I exchanged c920 with three 3,3yf100v
so the voltage on p14 is now a little bit higher.
not 5,1v but 4,9v
we are getting closer 😄
No idea how to move on