Hi All,
this one is going to be a bit tricky to explain: the erratic behaviour of my BG4000.
So far I have observed the following issues:
activate ON, the arm moves in one cm or two, stops and nothing else is happening ?
activate ON, the arm moves in about the same distance and lowers way before the dropdown point.
activate ON, the arm moves to to dropdown point, stops but nothing else. I I “finger-activate” the solenoid everything works on as normal.
activate ON, everything works normal as it should…and that can go on like this for half a dozen records without a glitch and then out of the blue is playing up again ???
in all those scenarios the main platter spins.
i am sorry, but I can not find any meaningful explanation for that behaviour or simply put don’t know where to start.
those brass contacts which may potentially be the source have been cleaned multiple times.
Perhaps one of you guys can make sense out of this - I would be very grateful indeed.
ALF
Thank you to our Sponsors
Beogram4000 behaving erratically
17 replies
Alf
When you say you have cleaned the "those brass contacts" are you talking about the carriage transport switches?
I have had similar strange behaviour on a BG4000 deck that was eating my lunch for days....intermittent faults. Finally traced it to the transport switches (one in particular) and it turned out that the actuating plastic nipple that operated the brass leaf switch was sticking every so often....I had thought i would lubricate these switches with silicone grease to keep them moving freely.....mistake! cleaned all the lubrication off them and everything was fine.....just a thought.
That is a interesting point - I actually used silicone spray for those plastic nipples not just at the carriage switches but on the keyboard switches as well….but I never had that trouble with other Bg4000 tables ??!
ALF
I’d say an erratic bulb perhaps? When it’s on its way out the deck will have the strangest behaviours…
Jacques
Well, two ways to interprete:
on its way out = about to die
on its way out (in) = approaching the drop down point, drop and play a record.
just today I played about 6 or 7 record sides in succession over the course of the day
and the BG hasn’t missed a beat…….?!
which means precisely nothing as it is just as likely to fail at the 8th records.
that is exactly the issue here.
of course I can keep taking transistors off the board and checking, cleaning switches but i do not believe that will cure it. Simply put: some component isn’t playing ball !
all I wish for is a consistent fault.
ALF
Is it a silly question,but is the carriage drive belt in good condition?
Silicon anywhere near those switch contacts is bad new's too!
Nick
No silly Q at all Nick, yes the servo belt is fine. I am just questioning the mentioned issues caused by silicon spray ??
i have never observed any issues with it like sticking on plastics etc.?? What I will do is getting all the plastic nipples out and wash them including their holders.
the reason I am sceptic is the BG works fine for a number of records and then all of a sudden something is happening and I wish I’d know what ?
ALF
It may well be something entirely different, however it only takes one switch to be out of step to create havoc with the logic controls. I do suspect the old timer design engineers decided to create the most complicated deck ever built, integrating complicated logic gates simply because they could.....logic gates that are still in lots of modern day control systems (albeit in sotware format these days)...bear in mind the only thing that opens the switch is the quite light pressure of the leaf spring contact....take a look i nothing else other than to eliminate them from your enquiries
This type of problem is of course tricky to trace as it's so intermittant,but I suspect a power supply problem.
Have you refurbished the machine Klaus?
Those reed switches that route the supplies,can cause all sorts of problems.The 6 volt regulator is a known troublemaker too.
If you can connect a meter,then when the problem occur's again,check if anything is missing?
Could temperature have some bearing?Do you leave the machine in standby,or disconnect when not using?
Freezer spray might provoke the gremlin?Try around the power supply board.
Nick
Martin recommends moving the voltage regulator 2TR6 from the 2 PCB and mounting it away due to heat issues.....I cant recall exactly but I have a feel ing the logic switches state around 0.5 to 2.5vdc and its the IC that supplies the power to "wet" the switch contacts I have a feeling that it all goes tits up if you dont have 4vdc min......
Please Log In to Reply
You must be logged in as a BeoWorld member to post replies to forum threads.
or
Join BeoWorld
Register to access the forums, reference material, and exclusive member benefits — including our monthly prize draw.
Become a MemberDecember 2026 Prize Draw
Gold Members OnlyAs a Gold member you're automatically entered into our exclusive prize draw — your chance to win iconic Bang & Olufsen products. A unique benefit of BeoWorld Gold membership, every draw brings a new opportunity to win something special.
1st Prize
2nd Prize
3rd Prize