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

Hi,

I wish you luck - one learns a lot about these receivers if it is a ‘to restore unit’ 🤗....but I am not saying yours will be one 🤞

with the help of some of our treasured experts I revived two....one is still in intensive care.

still fighting the volume issue - one of the problems is getting the genuine ICs without wasting time and money on fakes......

Luckily I have another donor unit coming to exchange some boards to see what exactly  is playing up....

still chasing some genuine AD7110KN ICs - my second delivery was labelled almost beyond recognition, meaning another delivery of fakes 😡

again I have gone over the tone/filter board, where quite obvious something is not as it should be....

gently!! tapping on P28/29 connectors responds with a horrible crackling noise.

both interconnecting flat cables (P28/29 to uP board) were fine, no wire-break, all showed healthy resistance.

all solder joints look healthy as well - I don’t want to remove the two IC sockets for the AD7110KN pair - that should not have any impact

as both are soldered in perfectly!

anyhow, thank you all for your interest in the problem...

ALF

back to the Tone/Filter board,

something that seemed odd - can't imagine that would be original ?!

first two pictures (solder side & component side) show cut tracks between Stereo and Loudness switch and "fly wireing" between those switches

but why ??

solder side of cut tracks

the next two pictures show a cut track of the Signal switch and the 'fly wireing" from the Signal switch D18/D17

last picture is the component side Signal switch "fly wireing" to D18/R25

can someone shed some light why this would be necessary ?

as always - many thanks

ALF

No comments on those rather strange tone/filter mods ???

anyhow, another donor unit arrived and I was keen to swap over its control board to see whether the volume issue has gone away....

NO - it was still the same 🤬

I began to wonder if it would have been too much coincidence that both boards had mal-functioning AD7110 attenuators?

yes, possible but likely ???

question: who would be the next suspect on line here ? 

I will move on to the preamp board, however still trying to make sense out this !

as usual, any input would be most appreciated - it feels like I am almost there......😳

ALF

No comment on the board someone modified. I couldn't tell you why they did what they did so I would use an original as a guide to put it back right.

It is pretty unlikely that the latest unit you received also has faulty volume control ICs. I would try swapping the microcomputer boards (before altering anything).  Same goes for the preamplifier board. 

John

Hi John,

thanks for your comment - swapped over the uP board as suggested first.....same outcome - that is with the tone/filter board from the “new” donor unit.

will move on to swap the preamp board but want to recap it first - no point running into way out if spec caps (the red Roe ones) and its consequences.

report back as soon as....

ALF

So are you saying that in the Beomaster 8000 that has the volume problem you are currently using a different filter & tone control board and a different microcomputer board?  If you switch the preamplifier board next I would first try it as is...before changing anything. If the problem persists then start changing the cables between the boards, one at a time, checking the problem after each swap. 

John