Beomaster 7000 2-way does not work

[filip_kbh]

After recapping my Beomaster 7000 the 2-way communication does not work. I originally did the recapping because the amplifier was getting a bit hot even though the idle current was set at 11 mV. The good news is that the Beomaster is almost completely cold now. The bad news is that my beloved 2-way function is not working. Any idea what could be wrong or where to look. I have the service manual but not completely sure what to look for.

Location: Copenhagen

[Die_Bogener]

Have you checked the lithium cell 3V and the option programming?

The display is ok?

The ir sender use a pretty high voltage… 32V when i remember right… and the axial caps are pretty old. I found already some of them with a short, and a burnt resistor on the display.

But it can also be dirt on the red plexy glas.

[filip_kbh]

I replaced the 3V battery – didn’t actually need to as it measured 3.1V after all these years still.

Yes, I checked the option.

The display is okay.

I replaced on the front panel these capacitors – they all had very high ESR measurements

C15 1uf/100V ESR 40.3 BAD
C19 2.2uf/63V ESR 14.2 BAD
C20 10uf/63V ESR 2.30 BAD

After this, I checked that the amp was working but I did not check 2-way communication.

I also replaced 2 capacitors on the CPU board – both of them gave no ESR whatsoever:

C1 100 uf/10V – measured capacitance 14.7 – way out of spec

C57 47uf/10V – measured capacitance 11.7 – way out of spec

So, I presume that I may have done something wrong with one of these capacitors – or they need to be a certain brand. The two from the CPU board were the blue Philips type as well as two from the front panel.

 

 

Location: Copenhagen

[Guy]

What remote are you using, and have you checked its two-way functionality with another Beomaster?

Location: Warwickshire, UK
My B&O Icons:

[filip_kbh]

I have a Beolink 7000 and Beolink 5000. Both of them worked before I recapped the Beomaster. Highly unlikely that both of them would fail at the same time – especially since I repaired their 2-way communication module 1-2  years ago.

Location: Copenhagen

[Guy]

filip_kbh wrote:

I have a Beolink 7000 and Beolink 5000. Both of them worked before I recapped the Beomaster. Highly unlikely that both of them would fail at the same time – especially since I repaired their 2-way communication module 1-2  years ago.

Ah OK that makes sense. I have to replace the caps in my BL5000 a couple of years ago when the two-way suddenly stopped working.

Location: Warwickshire, UK
My B&O Icons:

[filip_kbh]

Hmm – I have a hard time trusting my ESR metre. On the front panel board, I get open line readings on these:

C3, C5, C7, C8, C9, C11, C12, C16, C18, C23, C24

However, testing with the multimeter, only these ceramics give me no reading/reaction:

C5, C11, C23, C24. Still it’s a lot of ceramics …

Putting power on the board, only C5 is suspicious with a voltage across it of 0.142 V DC

Location: Copenhagen

[filip_kbh]

Hm. I have about 28V on the diodes

Location: Copenhagen

[Die_Bogener]

Have a look at the connectors…

[skolesen]

To check that the TX IR LED is active (transmitting) you can use the front camera on a iPhone or iPad.

 

/steffen

Location: Hvidovre, Denmark

[Die_Bogener]

“on the diodes…” or around the diodes?

“At” means dead diodes… at least one has died.

… and yes, there are around 40V around them. TR10 is the switch to fire them up…

… and a dead C19 can fire them… literally until they crack.

[filip_kbh]

Regarding TR10:

Base to Collector: 0.570 V 3.3 M Ohm

Base to Emitter: 0.273 V 333 Ohm

The diodes have been tested and they check out fine. I have inspected the board and there are no cracks as far as I can see.

Location: Copenhagen

[filip_kbh]

I’m getting a little bit frustrated. 1-way function was working. I decided I wanted to play a new record that I bought today, so I assembled the Beomaster. Now, IR does not work at all. And I didn’t touch anything. Must be a connection, I guess.

Location: Copenhagen

[filip_kbh]

Well, that was an easy fix. A wire had broken off. After soldering it on, I also soldered one pin on the big chip on the panel as it looked slightly suspicious, and now 2-way IR is back. It now reports the radio channel. Yay! Still no read out of Volume, and it seems like the range is limited.

Location: Copenhagen

[Guy]

Great news about the easy fix.  Those wires between boards are becoming more and more of a problem as the equipment gets older and more delicate/brittle.  I worry every time I put my BC9500 into the service position – there are just so many connections that could fail!

Location: Warwickshire, UK
My B&O Icons:

[filip_kbh]

Also no readout of RDS. Guess I will have to seek professional help.

Location: Copenhagen

[Die_Bogener]

You need a Beolink 7000 “RDS”…

Has it “RDS”?

 

Not all BL7000 can handle RDS.

[filip_kbh]

yes. I have an RDS BL7000. Worked before the recap of the BM.

Location: Copenhagen

[filip_kbh]

Finally had some time to look again, and also I understand the schematics a bit better now.

Checking the voltages on board P9. On pin 3 there should be 40V but I measure around 26V – it drops ever so slightly and keeps dropping until 25.87V when I measure with the multimeter. 40V is supposed to come from 2P14-6.

On board 2 P14, pin 6 gives me also around 26V – logically. Seems like it passes through C10 which I did not change – it measures 57uf capacitance and should be 47 – so I guess it is slightly out of spec – could that be the issue?. P18 measures the specified -40V.

On board 2 P24 should give me 11V but it gives around 5V.

Any help is appreciated.

 

Location: Copenhagen

[filip_kbh]

Looks  like D10 is shorted. Will change it.

Location: Copenhagen

[Author]

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