[herrit]

I was recently pointed in the direction of https://www.quality-dream-audio.co.uk/ by a forumite on here, and couldn’t have been more happy with the service. They are near Lewes, E Sussex.

 

If they are unable to supply parts for you, https://www.beoparts-shop.com/ in Denmark have also been very helpful.

 

HTH

(I am based nr Haywards Heath)

[herrit]

Steve at Sounds Heavenly wrote:

I’m pleased that B&O aren’t standing still with their design [snip]

There is more than a whiff of irony there, with B&O rehashing a 50 year old design ?

[herrit]

Wilco ?

[herrit]

Thanks everyone! Quality Dream Audio are so close that I have booked a visit on Thursday. Fingers crossed that it is a simple fix …

[herrit]

Many thanks for the replies. I’ll try to answer them in turn…

• The cartridge was re-furbished by a well known UK B&O specialist independent, who seem to be well regarded. Not sure if it is fair to identify him just now, but his diagnosis was “It is suitable for a rebuild / Coils good / Diamond heavily worn not suitable for suspension only / Suspension failed”, and so I went for a “Nude Elliptical Diamond, Aluminium cantilever”.
• The problem _could_ be a poor connection between the turntable and the amplifier, but why would it _always_ push sound through the LH channel at needle drop & needle rise only?
• The cartridge looks to deflect fine when it lands; the tracking force on the slider was cross checked with a stylus balance scale.
• Sadly I don’t have access to another Beogram.
• I am based in Sussex / UK.
• I can’t find a suitable external phono pre-amp to use with the Beogram and a Sonos ZP120 amplifier, but plugging the deck into the Sonos and raising the volume a _lot_ (due to no phono pre-amp), both channels seem to be at the same volume.
• If this last bit means that there is something wrong with the Beogram phono lead and/or the Beomaster 5500’s phono input, then what to test next? It does seem strange that the briefest of unmuting only happens at needle drop and needle raise though.
• I am awaiting receipt of an opto-reader for my MCP before I can try connecting the Beogram back up to the Beomaster – I will try the phono RCA inputs next – as the volume is too loud and I can’t at the moment reduce it (the MCCP will only raise the volume, not lower it !!!)

[herrit]

I don’t have another, no. And they are sufficiently expensive that I am hesitant to want to buy one if possible

[herrit]

With the cartridge removed I get ~ 764 Ω on both channels, and OL across the other pin pairs. So combining both of the above two replies I think that a) the cartridge itself, b) the wiring to the mute switch and c) the mute switch itself are all doing what they should be doing.

Interestingly, with the power to the turntable removed, but the phono plugged in to the Beomaster, the mute switch _does_ mute / unmute the LH channel when I press on the lever with my fingers. Not sure if this matters or not, but when the mute switch is released (ie unmuted), I do get some additional hum from the LH channel if I touch the metal shielding on the switch body.

But with a record on I still only get the briefest of sound out of the LH channel when the stylus is lowered or raised.

[herrit]

Thanks; with the MMC4 back in, I get the following resistances … but am not sure how to interpret them. Might I have some assistance?

I’m still not sure whether the channels are vertical or horizontal.

TIA

 

[herrit]

There are four terminals coming out of the back of the muting “switch” – just below the “11” on the board; the lower pair show OL when the switch is “out”, and 0.2 Ω when in. The top pair show OL & 0.4-0.5 Ω. The leads themselves measure 0.2 Ω, so does that suggest that it is the top pair that are not making “perfect” contact (ie 0.2 – 0.2 = perfect, but 0.5-.02 isn’t)? Forgive me, but I am very new to all of this.

If I check the left hand (vertical) pair of contacts then the readings are OL & 0.3 Ω, and the right hand pair are OL & 0.2 Ω

In the other thread it suggests shorting the muting switch; how do I determine which contacts need shorting?

 

[herrit]

I have just fitted the new muting relay and the Beomaster is sounding great again. Thank you to all for your input.

PS I meant to say relay and not transformer in my previous post – sorry. But I did take the opportunity to replace the 8 transformer mounting bushes which had failed.

[herrit]

Thanks everyone – very helpful. I swapped the speakers over to #2 and the problem goes away, so will focus on the muting relay.

Firstly, would I be right that the power relay is by the large transformers, and the muting relay is close to the speaker outputs? (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. I have not yet removed the transformer, so it was measured in situ.

 

You may have gathered that I am a beginner at such things, but I do have a multimeter, and ESG meter, soldering equipment, IPA & some Dioxit.

[herrit]

Sorry for not being clearer. By “drive pins” I mean did mean the capstans, yes – I had thought that the capstans were the plastic “gears” that go through the centre of the cassette. My bad.

• When I turn the deck on the capstans (and flywheels below etc) are stationery
• When I press PLAY (on the slide out control panel or front panel or Master Control Panel) the capstans rotate & the tape plays
• When I press STOP on the fascia the tape & the capstans stop. (The capstans actually continue to rotate for ~4 seconds, then stop).

• When I press STOP on the slide out control panel OR the Master Control Panel the tape mechanism stops & the pinch rollers retract, BUT the capstans do _not_ stop rotating, unless I press Play on the fascia twice, and/or turn off the power.

Glitch wrote:

I assume that you are asking about the capstans? I’m not familiar with the BC5500, but on other Beocords the capstan turns whenever the deck is not in standby. Glitch

 

Thanks @Glitch – it looks like what I have then is “normal” for a B&O tape deck. But it does seem strange behaviour to me, and can’t do much for prolonging component wear.

[herrit]

Thanks both – very interesting. I never realised that the second arm on the Beogram 5500 was there almost just “for show” !

[herrit]

The small vertical white plastic “pin” has broken on my Beogram 5500 too; I designed and 3D printed something that _should_ work OK, but I have yet to install it. More robust than the original, and weighs virtually nothing.

Will let you know if it works!

[Author]

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