tricky to capture - hope you can see the difference on the imprint on the two ICs:

Lettering is printed. Should be laser-engraved.

Counterfeit, I'd say.

Martin

I can’t possibly speculate whether those AD7110KN attenuator chips are a “popular source” of vol7me issues  ?

disappointing, it is such a pain to find some good parts these days - practically everything seem to come out of China - there is no real supplier choice !!

I gave it another go from a different (chinese) supplier 🙄 and ordered some more AD7110 ICs. Everything seem to point towards the 

tone/filter board and its volume attenuators....can’t think of a different problem source unless all power transistors in both channels are dead....

but then the fault switch would become active .....or is it ?!

let me repeat:

all interconnecting cables/connectors are fine - appropriate volume signals are coming through from the uP board to the tone/filter board, both attenuator ICs are getting the vol signals!

any other ideas......?

ALF

Hi everyone,

back on the job finally delivered a win.....

one question remains: what is a stupid mistake ?

I dare to say there isn’t one as we all do “those” in moments of distraction, frustration, tiredness ect......

gone back to the SM and its table of interconnections between boards - rechecked the wiring again....guess what ?

4P27 was connected to the wrong plug !!! 🤬 which was the reason for the “volume issue”

for now one of the two patients BM8000 is working fine and enjoying life again  — 🤗

the work now turns to the other BM8000 with the obvious similar “volume issue”.....no, all interconnections are fine 😬

which brings me to the last comments and replies about fake ICs....a new lot of volume attenuator chips AD7110 is coming

as this time it looks as the problem is on the tone/filter board ?!?!

again, the volume can be turned up and down with corresponding numbers on the display but nothing but a hiss is audible ?

will get back with some more news once the second lot of good “fakes” AD7110 has arrived.

in the meantime don’t hesitate to reply with alternative pointers or suggestions....

thank you

ALF

Hi Alf,

I'm glad you got the one problem sorted out. On my Beomaster 8000 restoration projects I started labeling both ends of all the connectors. Going by memory was not cutting it for me and it is much less stressful to just read and match the connector number on the cable with the board....with the exception of the preamplifier board which had no room for B&O to print any connector labels.  While most of the connectors have keys there are two or three that have the same key and can be connected wrong, as you found out. 

John

I take lots of pictures at each stage of the strip down.....and before too, always helps

craig

Craig wrote:

I take lots of pictures at each stage of the strip down.....and before too, always helps

craig

Actually I sometimes still do......though I take a lot of pics from different angles, in my work I used to do a lot of site surveys and make lots of sketch's....now the digtal camera does all of that, and the pics get embedded in reports etc.

Craig 

am waiting for a Beomaster 8000 to arrive so am following this with interest. Seller claims is working perfectly but we shall see.