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All fine so far.
The fact that you actually have sound from the affected channel, even if only briefly, suggests that the wiring is fine.
The problem could be with the cartridge itself.
I have seen cases where sound is lost when the needle is on a record.
Perhaps a dying cantilever suspension.
Do you have access to another cartridge for testing?Martin
It has been a while since the last Beogram 5000 on the bench, but I seem to remember
when you lift off the dustcover hinge block, a small connector becomes visible.Martin
Cracked solder joints near the relay?
Martin
Firstly, would I be right that the power relay is by the large transformers, and the muting relay is close to the speaker outputs?
Yes.
(See attached image). I have never got involved with such transformers – might I ask for a bit more detail for “cleaning the contacts” and a view on the resistances shown attached. Some of them are very approximate as they were slowly falling during my measuring them.
Replace the relay. Cleaning will not be a long lasting solution.
I have not yet removed the transformer…
You don’t have to.
Martin
So, basically, you are comparing a 45 year old speaker still running on its original
capacitors that, ideally, should’ve been replaced 20 years ago, to two speaker models
that are currently available new in shops – and you find them lacking a little treble?Well… replace the capacitors to grant it just a hint of fairness.
Kits are readily available.Beovox S45-2 is an incredibly well balanced and sounding speaker, but it is not “audiophile” and will never be.
Keep in mind it was merely somewhere in the middle of the Beovox model range at the time.Martin
MINI 41K? – Are you sure?
Martin
What other speakers did you compare to?
Did you replace the capacitors or are the still the original?
Martin
I agree on the cleaning. A piece of paper soaked in contact cleaner pulled through the contacts – nothing more, or the very delicate platinum coating on the relay contacts will be damaged.
– And you may find that oxidation from airs moisture already did just that.
So – replace the relay.Martin
Anyone ever thought -or tried out modding any of their speakers? I have these Beovox S45-2 ones and I do like the imaging but feel like the tweeter driver could be replaced with a better one.
Why?
Martin
They are interchangeable.
But if yours is the version with the white “see-saw”-arm between the switch rows, check that it doesn’t bind.
Else – give it a good dose of contact cleaner to shift any dry lubricants in the release mech.Martin
Two different switch banks can be found in Beocenter 3300.
One cannot be easily diassembled – and it’s usually not necessary. Most will respond well to a shot of contact cleaner and a little exercise.Martin
In Beogram 6500 muting is not done by a relay but by a mechanically operated switch.
This switch does not break the signal paths, – it grounds them. This means, that a bad contact won’t cause silence but instead the muting will fail and sound will be audible when the needle lands on the record and lifts again.If you are sure, your amplifier is good, I agree on:
– Cartridge
– DIN solders
– Broken tonearm wiring inside carriage housing
– Bad RIAA connection inside the Beogram
– Faulty RIAA
in that order.Martin
The white head of this arm should be on the other side of the cam wheel, operated by it.
Its head should be riding against a teflon sheet with a thick metal backing plate found under the platter.Take off the cam wheel, the metal plate with teflon backing and fit the arm correctly so that
it swings the tonearm when the cam wheel rotates, dampened to a smooth travel by the spring loaded teflon sheet.Martin
The solenoid should NOT be lubricated.
Martin
The solenoid is fairly sturdy. An electronic problem could cause damage to it, though.
There should be no oil or grease on/in the solenoid. It should be clean and dry.
Martin
If the Beogram didn’t lower the arm itself, it wouldn’t have deactived the muting circuit either.
Pressing down on the tonearm to make the needle touch the record won’t produce sound.Martin
What parts are not available?
Check if the motor bushing touches the metal bracket.
If it does – replace the motor mounts.
https://www.beoparts-shop.com/product/motor-suspension-rubber-bushing-grommet-f-several-beogram-beocenter-models-2/If the motor itself is noisy, it must be taken apart and repaired (most can be)
– or replaced, and a good condition used original motor would be the way forward in that case.Martin
In the OP, your first schematics are for Beogram 1800 (= Beogram 2000 but no datalink), and the next is for Beogram 2000 & 5000.
The RX-2 schematics shown in the same manual is wrong. It should’ve shown RCA plugs.
Martin
The Beogram RX and TX (R for Radial. T for Tangential) models were intended primarily for customers having a non-B&O receiver/amplifier.
They have twin RCA plugs from factory and none of them have datalink support.Martin
If the output stage transistors are held by a long bar with threaded brass inserts, the output
stage transistors are special in that they have a matching, relatively large, “hole” for the mounting bar.
If that’s the case PM me and I’ll have a look in the dungeons.– And check everything else in that circuit before powering up again.
Of course also check the idle current setting. Replace the trimmer, adjust and monitor the current while slowly powering up on a variac.Martin
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