Beogram 6000 (5512): Replacement of a Corroded DIN5 Plug with a New Gold Plated Unit

Practically all Beogram 4002/4 and 6000 need their DIN5 plugs replaced due to various levels of  corrosion on the contacts, which were not gold plated back in the 1970s. This Beogram 6000 (5512) is a 'beautiful' example:

and with the shield removed:

I cut the rusty plug off and installed a new gold plated all metal plug:

and with the shield on:

Beolovely! The CD-4 preamp board is next!

Beogram 8002: Taking the restored turntable for a spin

The last bit of repair on this Beogram 8002 is to fix the problems with the dust cover lid assembly. Meanwhile I started playing records on the Beogram as a test drive (or burn-in test). This is always the best part of the restoration.

I set up the Beogram 8002 in my office so I could listen to it play for the next couple of days. One of my kids is a trumpet player so I find myself listening to a lot of music by trumpet players. This picture is the Beogram playing Freddie Hubbard's First Light  LP. My copy has a very slight warp in it but the Beogram had no problems tracking it.

Once the listening tests are over and the dust cover assembly is re-attached this Beogram will be returning home.

Beogram 6000 (5512): Repair of a Wavy RPM Trimmer Scale Background

After replacing the background illumination bulbs in the RPM trimmer panel with LEDs I realized that the white  reflective background that homogenizes the illumination was wavy causing a 'zebra pattern' in the illumination:

This seems to be an issue that only affects a subset of Beogram 400x. I only had to do this once before so far. To fix it one has to take the panel assembly apart. This shows the panel from the back:

The white part needs to be separated from the aluminum panel. This can only be done by cutting the locking washers loose with a wire cutter:

Then the parts can be separated:

This shows one of the wavy white stickers close-up:

The wavy pattern causes a variation in the reflection of the light piped in from the previously installed LEDs. The original white stickers can simply be pulled up with pliers (one needs to be careful to not break the red dial hand off). Once removed it can be replaced by white electrical tape cut to size:

The panel can be reassembled by using new 3 mm circlips and nylon washers:

After this procedure the background illumination was smooth again:

Beotiful! On to replacing the badly corroded DIN5 plug...

Beogram 8002: Service Manual Adjustments

Going in to the Beogram 8002 service manual adjustments I already know that the fixed arm and tonearm horizontal parallelism needs adjusting. The tonearm appears higher than the fixed arm as you can see in this picture.

The tops of the two arms should be the same height and that height should be 19.5mm from the top of the Beogram platter. So the fixed arm needs to be adjusted up and the tonearm needs to be adjusted down.

To make all of the necessary adjustments I have to get to the underside of the tonearm carriage assembly. That means removing the rails and the tangential drive screw. I have to do this anyway to clean and re-apply some lubrication.

The red arrow in this picture shows the adjustment screw for the tops of the arms (the horizontal parallelism adjustment). The green arrow is for the vertical parallelism adjustment (the gap between the two arms). I am pointing that out as it turned out I needed to adjust it as well.

After adjusting the horizontal parallelism I got both arms to the 19.5mm height from the platter surface.

I installed a new tangential arm drive belt.

I also cleaned and checked the lubrication of the platter hub. The following pictures show the Beogram from platter hub removed to the sub-platter re-installed. I was able to find a spare tonearm assembly cover trim piece. The original one was missing from this turntable and the wires were exposed.

When I put the top platter back on and connected the main board the tonearm and platter worked okay but I noticed something was not right with the tonearm. When the Beogram 8002 tonearm is at rest you should be able to push the arm towards the fixed arm and have it spring right back to centered position when you let go. With this tonearm I was detecting an obstruction that was hindering the spring back action.

I was concerned at first because I couldn't see anything wrong. The vertical parallelism looked correct. I took a peek into the tangential arm tracking sensor assembly.

Note the spring clip in the picture below. That spring mechanism moves the tonearm back to a centered position when you move the tonearm away from the fixed arm.

Everything was fine in there. Nothing was scraping.

I finally realized the tonearm vertical parallelism adjustment screw was the problem. It had been adjusted incorrectly. While the gap between the fixed arm and tonearm looked fine, the tonearm raise/lowering bar was not operating correctly in the V-shaped channel of the brass adjustment screw.

The following picture of one of my own Beogram 8002 turntables shows the tonearm lift/lowering bar and the V-Channel adjustment screw. The lift bar has a spring mechanism that will attempt to keep the bar pressed down on the V-channel when the arm is in the raised position (not playing). If you manually move the tonearm towards the fixed arm the lift bar rides up one side of the V-channel. When you let go the tonearm should pivot back to a centered position as the spring loaded lift bar returns to the bottom of the V-channel.

On this Beogram 8002 project turntable the lift bar was getting slightly stuck at the top of the V-channel screw when the tonearm was moved towards the fixed arm. By re-adjusting the V-channel screw (which is the vertical parallelism adjustment screw) I was able to get the tonearm back to its normal, springy self.

The tonearm and fixed arms are also vertically parallel to each other.

I test played one complete side of a record and observed the linear tracking working correctly as the stylus remained always centered. I could see the tangential arm assembly motor adjusting the tonearm position pretty much ever half turn of the record. Very nice results after all of that disassembly/reassembly of the Beogram mechanics.

The last check I wanted to make was the voltage level of the light driven sensor in the control panel. This is for the Beogram forward/fast forward and reverse/fast reverse function. After the Beogram has been operating for at least five minutes the voltage of the forward/reverse sensor should be around 620mVDC in its normal state. This check is done my monitoring control panel connector P5-4 to P5-3 (ground) and P5-6 to P5-3 (ground). To adjust the sensor voltage levels there are two screws on the control panel that operate an aperture for the sensor lamp source as seen in the picture below.

The procedure requires checking the voltages at both test points a few times as each screw is adjusted. Each adjustment screw can affect the measurement at both test points. After a few iterations I got the sensor to a satisfactory level.

Tomorrow I will re-assembly the Beogram 8002 (except for the dust cover lids) and do some actual record playing testing.

Beogram 6000 (5512): Replacement of the Sensor Arm Bulb with a FlexPCB Based LED Assembly

The final light bulb to replace with an LED in the Beogram 6000 that I am restoring right now was the bulb in the sensor arm. It is arguably the most difficult bulb to replace due to the space constraints, as well as the design of the control system, which demands that a current comparable to a light bulb flows though the light source in the sensor arm. More detail about the specifics can be found in this recent post where I implanted it into a Beogram 4002.  Here are a few impressions of the process for this particular Beogram 6000:

This shows the original light bulb:

This is the replacement assembly based on a Kapton flex PCB that folds into the bulb compartment and places the LED in the right spot:

And this shows the LED in action:

Like all Beolover parts featured in this blog, this assembly is available to other enthusiasts. Just send me an email or use the contact form on the right.

Beogram 8002: Recapping Complete

For the replacement of the electrolytic capacitors I will pick up where I left off...with the Beogram 8002 transformer box that I opened up. The 27uF capacitor for the motor circuit will be replaced using Beolover's nice 3D printed assembly. I like to measure the old capacitors to see how many are bad, out of tolerance or on the verge of being out of tolerance.

The original 4C1 27uF capacitor of this Beogram is out of tolerance by almost 20%. 

The replacement part just drops into the transformer box and the two leads soldered to the new 4C1 27uF capacitor. This is a bipolar capacitor so it doesn't matter which wires to connect to the capacitor module leads.

That is way better than soldering a new capacitor and letting it dangle loose inside the transformer box.

The next capacitor is the 2C28 47uF capacitor in the microcomputer case. I cleaned off the old thermal paste (that was starting to dry out) from the microcomputer integrated circuit and the heat sink. The 2C28 capacitor was replaced and new thermal paste was added to the heat sink. The replacement of the 2C28 capacitor is a little tricky as the negative side of the capacitor must be soldered to the board on both the trace side and the component side as noted by Beolover a while back.

For the Beogram 8002 main board I replaced all of the electrolytic capacitors 2.2uF and less with WIMA MKS capacitors (the rectangular, red capacitors in the picture). The rest were replaced with new 105°C, long lasting electrolytic capacitors. For the large 1C27 2200uF, 50V capacitor I like to use the three prong base off an original Beogram 1C27. I had a spare base so I used it here.

The center hole is for the capacitor positive lead. I take the capacitor negative lead and solder it to the metal base. After that I use black hot glue to secure the rest of the capacitor to the base and place it on the board. This makes for a solid installation of this capacitor like the original.

The last two capacitors are on the Beogram 8002 chassis - 0C1 and 0C2. These are easy to get to. Just remove three wires (the yellow, black and blue).

The next picture shows how close together traces are on the Beogram 8002 main board. When re-flowing the solder joints of the board connectors it is best to use a smaller tip on the soldering gun. If the tip is too wide it is really easy to accidentally create solder bridges between traces. I have to use a magnified lamp when soldering on this board to tell if the result is good.

That completes the electrical restoration of the Beogram. A quick check of the work with the Beogram turntable assembly verifies that everything is good.

Now it is on to the service manual adjustments which will make sure this Beogram is ready for full use again.

Beogram 4004 (5526): A New Arrival from California

A customer in California who already bought some Beolover parts for his Beogram 4004 (5526) recently decided to send me the entire unit for a restoration. Unfortunately, it arrived with a bit of damage due to sparse packaging. I can only recommend watching our Beogram 400x packaging videos on the 4002 and 4000 pages listed on the right. So far, we never had shipping damages with the packing technique outlined in the videos.

Here are a few first impressions of this 4004:

This is how it looked after I took it out of the box:

The RPM panel was not taped down and therefore it liberated itself and unfortunately caused a few minor scratches on the keypad:

I think one could still recover from this damage and restore this pad to a fairly pristine state. Another area with issues is the tonearm:

It is missing its mounting screws. This Beogram was also shipped with a fairly new looking Soundsmith SMMC 20EN cartridge on the arm without much protection except a plastic tube and some bubble wrap:

Miraculously, this cartridge may have survived the dangling RPM panel and the loose arm:

The cantilever seems still straight, but I would need to do a few measurements to see if it is indeed undamaged. There are a few more cosmetic issues around the unit. One is the broken off aluminum trim on the left side of the hood:

Another is a crack in the veneer of the plinth on that side:

The platter also has a few marks:

There is nothing one can do except finding a better platter. On the positive side, this Beogram has very nice plinth corners at the front:

Under the hood I found a mostly original set-up

except that the Beolover tracking sensor light source has been already installed:

Due to the condition of the carriage/arm I did not turn the unit on yet, but it was immediately clear that the platter motor has issues. It can only be turned with some force, indicating that the bearings need attention at a minimum. 

So in summary, this unit is in a bit of trouble, but could still be returned to a pristine state if a better looking platter and hood with intact trim could be procured and the keypad would be restored.