Beogram 4000 TT schematic. - Page 2

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Re: Beogram 4000 TT schematic.


I don't need to waste any time replying in detail to
Mr T's blatherations, which mainly set out to discredit me.

He missed the part where I said I thought I would be compelled to get a
workshop manual
and schematic after spending more time yesterday on the POS B&O.

However, after an hour today I discovered more about what was wrong, and
about what
would never have appeared in the manual, since it involved
a very slightly broken plastic part.
Then there were some more obvious simple adjustments.

Once I fabricated a metal reinforcing bracket to beef up the plastic part
and adjust a position of a solenoid, and an adjust screw to minimise the
lateral play
of the arm cariage, the chattering stop/start action of the carriage ceased
and the item now runs flawlessly, nothing gets hot, and I was able to play
several records ok.
I think B&O have an inherent design problem with the 4000.
The solenoid controlling the arm lift/set down motion pushes against a  lever
which
stays against the threaded rod which is rotated to draw the carriage across
the record.
Clearly whoever designed it this way made a blue for not allowing enough
space
to prevent the solenoid shaft and lever striking the threaded rod and
bouncing a bit,
enough to make the solenoid act like a buzzer if the adjustments of solenoid
position
and threaded rod position are at extremes of their travel.
Basically,things are too crammed in, and I wouldn't have been the first
to find this problem. Anyway, the item is fixed now.

I might add I don't have a schematic and manual to use when playing chess
in my local group of players; sometimes you just gotta come up
with a solution without any aid.

The B&O cart has rather dull HF imho.
The Denon 103 MC in a Thorens TD160 is far better.

( Never did I say I had a Decca.)

Patrick Turner.



"Mr.T" wrote:

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Re: Beogram 4000 TT schematic.




<Snip Patrick admitting it's not so complicated after all, a person with no
experience can even fix one without a service manual. :-)

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If it's 30 years old I'm *NOT SURPRISED* !!!!!!!!!!!!!!!!!!!!!!!

And the MMC20CL I used was not the original, but did have an almost flat
response to 40 kHz, and came with an individually tested B&K plot to prove
it.
Any dullness when new would be due to poor load matching, the records
played, or Patrick's hearing.
(No longer made though unfortunately, so Patrick will never know)
Also I would bet money that it did less damage to a record than any moving
coil cartridge!
(Always my number one priority with vinyl, my Thorens has a Shure V15VMR)

MrT.





Re: Beogram 4000 TT schematic.




"Mr.T" wrote:

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Many things from 30 years ago had excellent bw.

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The unit I have had a normal B&O cart, and the whole unit
was suitable to give quadrophonic sound.


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I used to have V15.
Denon MC was much better.

I am still seeking a scematic for the 4,000 TT,
to check my work, even though it now appears to work perfectly.

The client wanted me to fix it before taking it to Melbourne
when he leaves town, so there wasn't much time to
order a manual from OS and wait a month for it to arrive.

There is a B&O discussion group to which I have
subscribed, and gues what, another guy has the same trouble
with vibrating/chattering arm when stopping/starting.

Don't worry Mr T, I normally perform blameless
repair work on all items.

I must say your posts have not been of any real help.

Patrick Turner.

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Re: Beogram 4000 TT schematic.



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Sure did 30 years ago. Cartridge suspensions don't seem to last that long
though, unfortunately.

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Any cartridge can manage SQ or QS. The standard cartridge was NOT CD4 rated
though, the MMC6000 was optional as was the decoder board.

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In your opinion obviously. Not all V15's are the same BTW! They are all
kinder to vinyl records though.
The idea of a record sounding slightly better, but once only, didn't appeal
to me that much.
Fortunately vinyl problems are irrelevant since the invention of CD.

MrT.



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