Repairs & upgrades

Part

Relay replacement

The original relays in the BeoGram 4000 series wear out with age. I replace them with my own relay PCBs, built around modern Omron relays.

Part

LED tracking sensor

The BeoGram 4002 tracks the groove with an optical sensor lit by an incandescent bulb that dims with age. I replace it with a calibrated LED on a small PCB.

Part

LED RPM adjustment lights

The bulbs behind the 33 and 45 rpm scales on the BeoGram 4002 and 4004 panel have usually burnt out after more than 40 years. I replace them with a warm white LED PCB of my own design.

Speed testing with SpinDex

Every BeoGram 400X I restore is speed tested with SpinDex, an open source RPM logger I designed for the BeoGram 4000 series.

Part

RIAA preamp

A new RIAA preamp for the BeoGram 4002, built around the OPA2134 in the same form factor as the original board. The second SMD prototype is built and tested.

Part

Sledge motor

The original sledge motors in the BeoGram 4000 series can get noisy and unstable, and their bearings can't be serviced. I replace them with a modern Portescap motor, with a Maxon motor as the alternative.

Part

Pickup mount

The plastic tab in the BeoGram 4000 pickup mount can break with wear and age. I replace the mount with my own nylon part and flexible PCB.

Restoring the keypad and chassis on a BeoGram 4002

Decades of use wear through the varnish and black paint on the BeoGram 4002 keypad. I strip it, have it professionally painted and refit it to the chassis.

Replacing the electronic components in the BeoGram 7000

The electrolytic capacitors in the BeoGram 7000 and its 59xx siblings have reached the end of their life. I replace them on the control board, power supply and motor board, along with the rectifier diodes.

Adjusting and lubricating the BeoGram 7000

After the electronics, the BeoGram 7000 gets new belts, fresh lubrication and a full adjustment to the service manual.

Adjusting the speed on a BeoGram 6500

After the capacitors, belts and lubrication, I measure the speed over a long run. This BeoGram 6500 ran at 31 and 43 RPM until it was adjusted.

Part

Backlight

A weak or dead backlight is the most common fault on the BeoLink 7000. The EL foil behind the display wears out, and I replace it with a new one.

Replacing the batteries in the BeoLink 7000

The BeoLink 7000 has two batteries, the main battery and a lithium coin cell that keeps its settings. Both are long past their life, so I replace both.

Cleaning and lubricating the BeoLink 7000

The display lift in the BeoLink 7000 runs on a small belt, gears and a guide rail. I clean and relubricate the mechanism, fit a new belt and replace the capacitors and fuse on PCB01.

Testing the BeoLink 7000

The BeoLink 7000 has a built in test program. I use it at the end of a restoration to check the keys, the display and the memory.

Part

Stainless steel top plate

The top plate on the BeoLink 7000 is almost always scratched or dented. I replace it with a new plate in mirror polished stainless steel.

Regluing the glass front on the BeoLink 7000

Now and then the adhesive between the glass front and its plastic frame starts to let go on a BeoLink 7000. As long as it hasn't come off completely, a syringe of thin superglue fixes it.

Part

Piezo element

Tapping the top plate wakes the BeoLink 7000, thanks to a small piezo element underneath. When that stops working, the piezo has usually failed with age, and I replace it.

When a new backlight foil doesn't fix a BeoLink 7000

A BeoLink 7000 still had no backlight after I fitted a new EL foil. The cause turned out to be a failed transistor in the backlight oscillator.