Beogram 4000 Restoration

****Most of our Beogram 4000 parts are available for purchase at the Beolover Store.****

Please, send an email to beolover@gmail.com if you need a part that is not yet available via the store.

This video shows how to prepare and double-box a Beogram 4000 for shipping (please make sure to also read this update about securing the carriage for transport, and this post about how to secure the arms with a reproduction B&O style elastic support):


This post shows how to place the cartridge into a Beolover MMC shipping container, which will be supplied along with the Beolover double box.

This video shows how to unbox and set-up a Beogram 4000 after it comes back restored:

This is a list of key Beogram 4000 related entries. They represent most of the essential tasks that I performed for full restorations and also give some insight into repairing miscellaneous issues. All the parts that I developed are available to other enthusiasts and shops - just use the contact form and get in touch!

Beogram 4000: Cleaning of the Tone Arm Carriage Position Switches and a Non-Returning Carriage

Beogram 4000: Recapping the PCBs

Beogram 4000: Adjusting the AC Motor Voltage (additional info here)

Beogram 4000: Restoration of AC Motor (this post shows how to fix a 'knocking' motor)

Beogram 4000: Replacing the Reservoir and Motor Capacitors Using a 3D Printed Adapter
(see here for additional information on this procedure). There is also a new part that uses a PCB-based approach to replace the capacitors. Much cleaner installation and it also includes a modern 24V power supply that will make your Beogram 4000 run much cooler and reduce the power consumption by 50% (almost 80% in standby mode).

Beogram 4000: Replacing the Light Bulbs in the Control Panel with LEDs
Please, read this post, which discusses a different keypad PCBs that can be found in some Beogram 4000s)

Beogram 4000: Restoring the Slow Slide Transport Function

Beogram 4000: Replacing the Light Bulb of the Tracking Sensor with a Drop-In LED Assembly
some more info about the photoresistors in the tracking sensor here.

Beogram 4000: Replacement of the Incandescent Bulb in the Sensor Arm with an LED

Beogram 4000 (type 5215): replacing sensor arm photo cell with modern one (it is a similar procedure for the 4002/4). Note that sometimes all that is needed is to glue the photo cell back into its small slot. 

Beogram 4000: Restoration of a Seized Solenoid to Tonearm Linkage

Beogram 4000: Adjustment of the Tonearm Height and Tracking Force

Beogram 4000: Adjusting the Platter and the Chassis

Beogram 4000: Adding a Grounding Switch to Get Rid of Humming. This post has some higher resolution pictures of the way the grounding switch can be installed.

Beogram 4000: Adjusting the Solenoid and the Switches

Beogram 4000: Installation of Hood Mounting Screw Springs

Beogram 4000: Polishing the Hood

Beogram 4000: Installation of a Brand New Hood! Since late 2022 there are brand new hood reproductions available!

Beogram 4000: Exchanging the Plinth Panels

Upgrades:

Beogram 4000: New Aluminum Carriage Pulley

Beogram 4000: New Main Capacitor Array with Integrated Efficient 24V Power Supply

Makes your Beogram 4000 run much cooler (~50% reduced power during play and ~80% during standby)

Beogram 4000: Gold Plating of Terminals in Control System Switches

Some faults and their repair:

Cracked/broken off MMC cartridge mount:

There are two types of cartridge mounts that were used in the Beogram 4000. Both break off occasionally. These two posts show how to replace
(1) the later type: Beogram 4000: Replacing a Broken MMC Cartridge Mount with a 3D Printed Replacement Assembly and

(2) the early type: Beogram 4000: Replacement of an 'Old Style' MMC Cartridge Mount with a New 3D Printed Assembly

Beogram 4000: Solenoid oscillates

Beogram 4000: Replacement of a Stuck RPM Relay with a Modern Encapsulated SMD Relay

Beogram 4000: Fixing a Bent Output Switch Contact Tab

Beogram 4000: Adjusting the Gap at the Carriage Servo Pulley Bearing

Beogram 4000: End Groove Detection Issue
(Carriage stops before end switch is reached when no record is present)

Beogram 4000: An Entertaining Evening Exploring the Differential Stop Circuit
(Carriage sometimes does not return and needle remains stuck in the final groove)

Beogram 4000: An Entertaining Evening Exploring the Differential Stop Circuit
(record detection works for 12" set down point but not at 7")

Beogram 4000: Intermittent "17" Position Switch Causing Immediate Touchdown After Launch

Beogram 4000: Prematurely Activating Solenoid
(After pressing ON the solenoid briefly twitches, then the carriage moves on normally to the LP setdown point)

Beogram: Hot transformer, weak motors, suddenly activating solenoid when mechanically tilting the carriage
(This post discusses what happens when the bolt insulator of a chassis-mounted transistor is omitted and if one of the push-pull transistors of the AC motor output stage is shorted out)

Beogram 4000: Choppily Rotating AC Platter Motor - Repair of Wien-Bridge Oscillator Circuit

(This post describes how to replace the automatic gain control bulb in the AC platter motor oscillator circuit with a resistor and a diode clamp)

Replacement strobe light: We do not have a part yet for the Beogram 4000 strobe light, but there is a supplier in Germany who sells LED replacements. Apparently, Dual used the same bulbs in their turntables. Note that it may also be the reed relay that controls the strobe if it does not turn on.

MMC Cartridge Repair:

We do not do it, but you can get your cartridges professionally repaired/rebuilt here:

https://www.tonabnehmerservice.de

https://audio-origin.co.uk/index.html

https://www.sound-smith.com/bo-cartridges

Joseph Long aka 'groovetickler'. Email: Cartridge_Retipping@outlook.com