[Dillen]

The very thin leads from the cone to the voicecoil tend to break under the lip of the center dustcap. It’s quite common for Beovox S120 and Beovox MC120.2.
Most can be repaired if you work carefully.

Martin

[Dillen]

Replace the standby relay. It must be hanging (welded contacts), allowing the output stages to be powered even in standby.

Martin

[Dillen]

Is it only the far right side of the cooling fin that is warm?
And how warm?

Martin

[Dillen]

Yes, wrong tracking force setting. Check it with a gauge and reset the scale if it is off.
Or damaged stylus.

Martin

[Dillen]

Resolder the relay for the amplifier.
Its solder joints for the coil cracks, making it impossible to pull the relay and close down the amplifier.
– Yes, this relay is active when the Beomaster is in standby.

Still no luck – replace the relay (new relay here).

Martin

[Dillen]

Bad solder joints?

Martin

[Dillen]

They are excellent decks, great performers and a fantastic design.
Absolutely worth restoring. Not sure why anybody would say otherwise.

Clean the laser lens.
Check if the drive suspension rubber parts have deformed, allowing the drive to sag down.
This typically causes the disc to rub on the tray when rotating, and it can cause many strange symptoms.
Replacing the tray belt is a two-minute job when the cover is off.

Check for cracked solder joints at connectors and other large components, and
particularly the center pins of the large filter capacitors.

And replace capacitors on the servo board (grab a kit containing the correct type of caps).
They can also cause many strange problems.

Keep in mind, that CDRs are not following standards. The same goes for many types of
copy-protected discs (“Copy-Control” etc.).
Most Beogram CD5500 will play CDRs without any problems, but it cannot be guaranteed
that all decks will play all CDR discs.
And not all CDRs age well. Over time they may lose information making them more or less unreadable.

Martin

[Dillen]

Gorgeous piece!

Martin

[Dillen]

I bought something on Ebay years ago called “liquid bearing”.

Martin

[Dillen]

Replace the wedge-shaped belt for the carriage motor.

Also dirt and/or dry lubricants towards the leftmost end of the threaded spindle can cause
excess friction and make the belt slip.
Clean the threaded shaft and add a handful tiny drops of teflon oil.

Martin

[Dillen]

You cannot tell if they are any good by looking at them.
They will be out of spec by now, that’s almost guaranteed after all these years.
Capacitor kit here.

Martin

• This reply was modified 1 month, 3 weeks ago by Dillen.

[Dillen]

Running the power output of Beomaster 8000 to the input of another amplifier (Beolab 8000 is an active speaker) could easily destroy both.
How did you connect it?

Martin

[Dillen]

It’s a mains phase issue. The metal chassis’ of your products are capacitively coupled to neutral, so if not phased correctly (coupled to live) a very small amount of AC current
will run through your body and to the ground you stand on.

Try rotating power plugs 180deg. Start with the Beomaster as it is the one with most connections to other products.

Martin

[Dillen]

A scope to the signal path would reveal the cause in a few minutes.
Lacking a scope you could compare DC voltages on the transistors in the preamp L+R sections.

Martin

[Dillen]

The problem is that the carriage is moving while the tonearm is lowering.
The diaphragm adjustment method can be found in the service manual.

And something in the damper linkage still doesn’t move exactly as it should, causing the tonearm
to drop fast if lowered soon after being raised.

Martin

[Dillen]

Nice video.
Wrongly adjusted tracking opto (diaphragm).
Could also be that the tonearm alignment is way off, but that’ll usually be visible, and yours doesn’t look that wrong.

Martin

[Dillen]

Was this problem also present before you started work on the Beomaster?

Martin

[Dillen]

The decoder is the module to the right of the amplifier module in this photo.
It has no visible leads out side this.

When Tape or Phono is selected as source, the stereo light should be lit.
If it flashes, it could be because of a bad switch contact or the lamp is not securely fixed in
its socket. Or the lamp itself is on its way out.

Martin
(Photo from http://www.vintage-radio.net)

[Dillen]

The stereo decoder module was an optional extra in Beomaster 900K.
Not all Beomasters had them installed.
If no stereo decoder module has been installed, FM reception will be mono only, and the stereo indicator won’t light up.

Martin

[Dillen]

And some versions have protective diodes at the datalink signals. They can short.

Martin

[Author]

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