[KolfMAKER]

Thnx Die_Bogener!

The issue of Auto stand-by clicking On-Off-On all the time, even happens when having no audio source connected to PL or RCA/Line in.

What about that ?

[KolfMAKER]

@Matador: thanks for sharing the leaflet!

@Geoffmartin: check.

[KolfMAKER]

Thanks @Matador!

Very interesting document. Thanks for sharing.

[KolfMAKER]

Very interesting @geoffmartin!

Great that you respond to this topic, as you have a lot of access to things. So very much appreciated that you like to share.

Is it possible that you share some pictures of what you describe as white and black sleeve versions?

 

PS.
Is this the Technical Sound Guide you are referring to?

https://tinyurl.com/4a72t56v

 

[KolfMAKER]

Interested to know more about what this is.

Is it a record, what is on it?

[KolfMAKER]

Thanks a lot Die_Bogener !

I now also noticed following. I touched the solder connection of the Left/Right signal wire (see red circle), with a screw driver. And immediately, the power switches ON. And when it is on, the hum/buzz gets stronger. Same happens (obviously) when I touch the back of the RCA connector (as it is the same connection of course). This does not happen when I touch the GND connection.

Concerning your advise to test by measuring (before plugging in the RCA):

• The voltage between source and 8000, both AC and DC
• Measure ground to ground
• And signal to signal

Just to be sure, do you mean …

• Ground & Signal at the RCA connector on PCB 05, at one side?
• And Ground & Signal at the P4 connector Amp PCB, as the other side?

 

[KolfMAKER]

That’s a real nice model. To be honest I did not recognize it first hand, but after a bit of searching I found it.

It’s the BeoLit Teena 609 AM, from 1962. AM only, battery powered, plastic casing, available in 4 colors.

 

Reference links:

• https://beocentral.com/beolitteena609am
• https://www.radiomuseum.org/r/bang_beolit_teena_609_am_exp_iii.html

BeoLit Teena 609 with FM: https://www.radiomuseum.org/r/bang_beolit_teena_609.html

[KolfMAKER]

Here’s another update. I made several other checks.

(Check 1) PCB 05 exchanged – I took the ‘PCB 05 Link shift board’ from another BeoLab 8000 and put it in the ‘trouble BeoLab 8000’.

(1) Result – Nothing changed. So, when nothing is connected to the RCA input on PCB 05: still a loud Hum. When an iPhone is connected to the RCA input, the hum is gone, Auto stand-by goes to OFF, but it also goes back ON again when I touch the 5-pin cable P4 on PCB 05.

So I conclude that the problem is not in PCB 05.

 

Observation: I noticed that when I touched the 3-pin JST cable from PCB 06 to the Amp, the Auto stand-by also switches to on. Same as when touching the 5-pin cable on P4 of PCB 05.

 

(Check 2) 3-pin JST cable changed – I hand-made another 3-pin JST cable to check if the original cable is the issue. This is to check if there is something wrong with the original cable between PCB 06 and the Amp.

(2) Result – When powering on, a slight hum/noise can be heard. Though it seems to be a higher pitch than before. Unfortunately, this hum/noise seems a bit to strong as the Auto stand-by does not switch OFF.

 

Observation: In the situation with the hand-made 3-pin JST cable, I noticed that when touching this cable or the 5-pin cable on P4 of PCB 05, nothing happens. Though, the BeoLab does not switch OFF.

 

[KolfMAKER]

I am not sure as I have never setup such system with new BeoLab’s. Nevertheless, maybe some questions and suggestions to think over.

 

• Did this setup work before (showroom/pre-owner), or is this a first install?
• Did you try to reset the BeoLab’s to factory standard?
• Did you try to reinstall or update the speaker firmware?
• Did you try to change the order in which you connect and pair the speakers?
• Did you remove the B&O configuration App from your smartphone, and than reinstall it again?

[KolfMAKER]

@Die_Bogener: As you suggedted, I connected a shorted RCA plug to the RCA connector on PCB05. Result: the hum is gone, Auto stand-by switches to OFF and stays OFF, and when touching the P4 cable, Auto stand-by does not switch on.

So this does look good! But now I need to make a next step, because I need the RCA connections, so I cannot keep them shorted.

 

Here’s some additional things I changed, tested and the results.

 

Checks 2

I took another look at PCB05: used a dentist tool to scratch along the edges of the RCA GND contact on the PCB, and at some other connections/traces on the PCB. Just to be sure, there’s no traces that make unwanted contact.

Tested after checks 2

1. Input switch set to RCA: When the BeoLab was switched on again, the hum was more or less gone. The Auto stand-by does switch to OFF, but after one second immediately switches ON again, and then repeatedly goes ON – OFF – ON – OFF.
2. Input switch set to PL: Auto stand-by switches OFF, and stays OFF > OK. Touching the PCB, P3 / 4 cables, etc. has no influence on Auto stand-by, it stays OFF > OK.

 

Checks 3

Extra checks on the GND and disturbances of the RCA plug on PCB05.

 

Tests with Checks 3

All checks done with the input selector set to RCA.

1. Connected a wire between GND of the RCA connector outside shell above the PCB, and the GND underneath the PCB. Problem remains > No positive result.
2. Put a metal cap over the RCA plug for shielding. Problem remains >  No positive result.
3. Connected my old iPhone with a ‘mini-jack-to-RCA’ cable to the RCA socket on PCB05 > No hum, Auto stand-by switches to OFF and stays OFF.
4. In situation 3. I also touched the cable of P4 on PCB05. When touching it, Auto stand-by switches to ON. When releasing the P4 cable, Auto stand-by switches OFF again and remains OFF.

 

What bothers me is, that the Auto stand-by actually works well, but …

Touching the P4 cable makes the Auto stand-by switch ON again. Therefor, it is not yet working reliably.

 

Questions

• What do you conclude from this?
• What next step do you suggest?

 

 

[KolfMAKER]

Thnx BeoTool!

In my case the RCA connector is not soldered to the PCB. It is fixed to the board by a nut, and I have tightened the nut well. So it must be another cause.

Any idea?

 

[KolfMAKER]

Findings

First I disconnected and took PCB05 and PCB06 out of the speaker. Checked again for foam rot rests. Did some extra cleaning to be sure. Then I made following checks and did resoldering.

Checks
PCB 05 – Link shift (in outside foot)

• Continuity: measured continuity on all traces and solder points connected > OK.
• Re-soldering: re-soldered all solder points, incl. connectors and component pins > Done.

PCB 06 – Stand-by (in bottom speaker casing)

• Continuity: measured continuity on all traces and solder points connected > OK
• Re-soldering: re-soldered all solder points, incl. connectors and component pins > Done.

P4 Connector (between PCB05 & PCB06)

• Continuity: measured continuity on all 5 pins of the cable > OK.

 

Next

After this I put the BeoLab back in original configuration: PCB06 screwed back in normal position, PCB05 connected but hanging loose. iPhone connected (as audio source) via external mini-jack to RCA cable, connected to RCA in foot. Result: There is a little hum, but Auto stand-by does switch OFF.

Findings:

• When the P3 connector or cable is touched, Auto stand-by switches ON. But when let loose, it also quickly switches OFF.
• When the P4 cable is touched, nothing happens.
• When the P6 connector (audio cable) on PCB05 (Link shift) is touched, Auto stand-by also switches to ON. But also, quickly switches OFF when let go. This also happens when the connector of this same cable on the amplifier side is being touched.

 

Question

There still is sensitivity in the audio signal path.
What is the best next step I could make?

[KolfMAKER]

@Die_Bogener

Thanks! I will make those checks and come with my findings.

[KolfMAKER]

To make this thread complete, here’s a picture of the by-pass wire correcting the broken trace.

 

[KolfMAKER]

After having made the by-pass wire for the T2 transformer and concluding it worked properly again …

I today put the PSU/AMP block back in the speaker casing, and connected the speaker panel. So back to the original configuration.

Having done some tests, and using the system for a few hours; it’s properly alive again!

Special thanks to: Beobuddy, Dillen and Die Bogener!

[KolfMAKER]

Thanks for your response Tignum, great info again!

Yes, I will do some reburbishment with Akustikstoff in the near future. I have several BeoLab 8000 grills with terribly looking cloth; wrinkles, holes, discolored, ect.

I do like the looks of Akustikstoff standard black, so that’s what it is gonna be. And I am sure it will look better than the original.

[KolfMAKER]

Update, after adding a wire between 7 + 3.

I added the wire and made a first check powering the system. Result:

• I immediately heard the relay clicking.
• The power LED became alive again; turned green and back to red.

 

Next I measured AC voltage on T2:

• Between 4 + 6 = 43 volts AC
• Between 4 + 5 = 22 volts AC
• Between 5 + 6 = 22 volts AC

Are these the correct measurements?

[KolfMAKER]

Thnx BeoBuddy.

 

So, you measure from 7 along the trace to point 3 where the trace is broken.

• Yes, confirm. From 7 to 3 there is no continuity.

But, you should have continuity between A and 1, and between B (through 7) and 3.

• Between A + 1 = continuity.
• Between B + 3 = no continuity.
• Between B + 7 = continuity.

 

Piece of wire between 7 and 3 will solve it.(or at the point of where the trace is broken).

• I am gone do that.

[KolfMAKER]

Thanks so much Tignum (fellow Dutchman!) This is really good information and the pictures speak for itself; wonderful.

There’s two things I am curious about how you handle that.

1. I think I saw that you put the HPX tape on the length of the plastic grill, but both on the outside and the inside.
   • Is that correct?
   • Does it mean the cloth folds for about 1.5 cm to the inside of the grill, so also covering the notches? (Because B&O utilizes a very small edge where they stick the cloth, not covering the notches)
   • If you make the cloth fold 1.5 cm how do you handle the the notches, so that they are not covered?
2. How do you handle folding the cloth (without wrinkles) around:
   • The circle shape of the top lid?
   • Around the corners of the top lid?
3. Did you order the cloth at Akustikstoff.com by the meter, or pre-cut?

Thanks again, looking forward to your tips.

[KolfMAKER]

So I did some measurements again.

• Between 1 + 3 = 0 volts / and also no continuity.

Also checked for continuity between the incoming 230v connector and Pin 1 and 3 of the T2 transformer.

• Between A + 1 = yes, continuity.
• Between B + 2 = no continuity.
• Between B + 3 = no continuity.

But I also found something interesting:

• Between B + 7 = yes, continuity.
• Between 7 + 3 = no continuity. (Visually I cannot see any broken trace)

 

[Author]

Posts