Sign in   |  Join   |  Help

BEOMASTER 6500 does not start up - one error found

rated by 0 users
Answered (Verified) This post has 1 verified answer | 22 Replies | 2 Followers

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er posted on Thu, Dec 24 2020 12:13 AM

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

 

Answered (Verified) Verified Answer

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
Answered (Verified) 69er replied on Sun, Jan 17 2021 2:47 PM
Verified by 69er

Hi Keri,

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.

 

best regards 

69er

 

 

All Replies

Schletti82
Top 500 Contributor
118 Posts
OFFLINE
Bronze Member

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 

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Thu, Dec 24 2020 12:36 PM

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

69er

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Sun, Dec 27 2020 3:18 AM

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

69er

Keri
Not Ranked
Chicago!
33 Posts
OFFLINE
Bronze Member
Keri replied on Mon, Dec 28 2020 7:31 PM

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  (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?

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Tue, Dec 29 2020 10:52 PM

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 

69er

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Tue, Dec 29 2020 10:57 PM

Hi Keri,

i replaced the broken capacitor and found a broken circuit which i soldered.

now I have the click on both relays.

on p14 I only have 3.754V AC

 

the main power shows 31,9 and 6,16 V AC

what to do next?

Keri
Not Ranked
Chicago!
33 Posts
OFFLINE
Bronze Member
Keri replied on Tue, Dec 29 2020 11:21 PM

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.

 

¡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?

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Wed, Dec 30 2020 5:14 PM

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 😎

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Sun, Jan 3 2021 8:08 PM

Happy new year B&O Fans

 

Any additional help?

best regards 

69er

 

Keri
Not Ranked
Chicago!
33 Posts
OFFLINE
Bronze Member
Keri replied on Sun, Jan 3 2021 11:47 PM

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.

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?

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Mon, Jan 11 2021 7:16 PM

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? 

69er
Not Ranked
30 Posts
OFFLINE
Bronze Member
69er replied on Mon, Jan 11 2021 7:16 PM

No, unfortunately no progress - i am not the expert in reading ciscuits :-(

 

When you say, did you check both electrolytics, which one do you mean? 

Keri
Not Ranked
Chicago!
33 Posts
OFFLINE
Bronze Member
Keri replied on Tue, Jan 12 2021 12:49 AM

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.

 

 

¡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?

jesperb
Not Ranked
79 Posts
OFFLINE
Silver Member

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

Page 1 of 2 (23 items) 1 2 Next > | RSS
Beoworld Security Certificate

SSL