Beogram 4002 Type 5513: Speed Test #3 Completed

The third platter speed test is complete on the Beogram 4002 restoration. This test was to check the platter motor speed stability after the Beogram main board was reworked (new capacitors, trimmers and RPM relay).

The result is even more improvement on the turntable platter speed. There were a few spikes in the steady state speed but the magnitude and frequency of the spikes are way less than the first two tests.

The next step on this restoration is the replace the RPM scale bulbs and the Beogram main reservoir capacitor.

Beogram 4002 Type 5513: Results of Platter Motor Test 2 - Beolover Rebuilt Motor

As were the results of other Beolover rebuilt DC Beogram platter motors, I expected much more consistent speed readings from this second twenty-four hour speed test. That is the case here but it is impressive to actually run and record the test results myself.

To restate this second motor test - I took a Beogram 4004 platter motor that Beolover already re-infused the bearings with oil. That motor is now in this Beogram 4002 and I recorded the platter speed for twenty-four hours with the Beolover RPM Measurment Tool. This Beogram hasn't had any of its electronics restored yet so they are still as I received them and as far as I can tell still operating with the original 1976 parts (perhaps 1975 as that is the date marked on the motor).

Here are the test results:

Quite an impressive improvement and it leaves no doubt in my mind the importance of this restoration service on Beogram 4002/4004 DC motors that are over forty years old now.

That is very consistent speed for twenty-four hours straight and all with an analog control system.

The next steps in this project are to send the 1975 DC motor to Beolover for that part of the restoration and I will continue on with the electronic restorations. I will work on the main circuit board next then run another motor test to check the speed stability again. That test isn't really necessary but I am curious to record the improvement provided by each step.

Beogram 4002 Type 5513: Results of Initial Platter Motor Test

After a little over twenty-four hours running I stopped the Beogram and loaded the measurement logging data into my analysis software. The previous post yesterday showed that the Beolover RPM Measurment Tool logs a timestamp HH:MM:SS and an RPM measurement every ten seconds. Plotting this on a graph of RPM by time gives the following result.

The top level speed for the selected 33 1/3 RPM turntable speed stayed pretty level but you can see quite a few dropouts down to a lowest speed value of 30.324 (at the three and a half hour mark).
Note that this result is consistent with measurements that Beolover typically gets on his initial testing for one of these motors.

Like Beolover's other Beogram DC motor tests, it will be interesting to see the result of this Beogram with a DC platter motor whose bearings have recently been re-impregnated with oil. I would also like to do that before doing any other restoration work on this Beogram so I can see the incremental effect each restoration task has on the motor stability.

Luckily I happen to have a spare Beogram 4002 motor that Beolover treated the bearings on already. So I'll install that motor in the Beogram and run the speed test again.

Beogram 4002 Type 5513: Start of a Vintage Beogram Project

This past week I received a beautiful Beogram 4002 Type 5513 (USA model) turntable to examine and determine restoration tasks. It came from the original owner who bought the Beogram new around 1976. Even though the journey for the shipment was not too far it was double boxed as it should be and inside the outer box was the original box. That is always so cool to see that.  The original box has special packing material that secures the turntable chassis, platter, tonearm and dustcover so everything is tight and cannot move. These next sequence of pictures show the unpacking from the Beogram box.

Normally the dust cover would be mounted around this section of the styro-foam mold (fitting on top of the platter). However, in this case the original dust cover is in great shape and doesn't require any work done on it....So we decided, why risk shipping it as it isn't required for any of the other restoration tasks.

The inner styro-foam is removed and here is the Beogram chassis.

Now it is time to look over the turntable and see what kind of wear and tear there is. Overall this is a wonderful example of the 4002. The wood is beautiful and I can't see any sign of fading. No need for any wood work type restoration on this one.

The control panel does show the usual wear from human oil. Our fingers leave permanent wear marks over time. Beolover offers a restoration of the control panel so we will see if that is something the owner will want to do here.

The two removable, aluminum deck plates reveal a bunch of deteriorated plastic pieces inside. No surprise and no concern about that. Those are the old transport lock bushings. The yellowish ones like this unit had are always broken into small pieces by now. All it means is a cleanup task and new bushings will be installed. The original guide washers for the cabinet's wood trim are also gone and replaced by regular metal washers. It would be a good idea to install the replacement guides that are eccentric shaped like the originals were.

Except for the deteriorated bushing pieces the interior is pretty clean. There is a little excess oil on some of the parts but that is easy to clean off.

The tangential arm drive pulley is crack free and appears to be in good shape. We still might replace it with one of Nick's aluminum pulleys.

Mechanically I don't see anything out of whack. The arms are decently aligned and I will go through all of the service manual adjustment checks later once the restoration tasks have been decided.

The arm lowering lever operates really smooth. None of the common stiffness to the movement there.

The DC platter motor is always a question. This one operates extremely quiet so that is a good sign.

So it is time to put on the top platter and bring out the Beolover RPM measurement tool.  Both the 33 1/3 RPM and 45 RPM speeds were off a bit.

I adjusted the speeds with the main board trimmers.

...and was able to bring both speeds into respectable range.

To really know how well the platter motor is doing I will have to let the measurement tool run for several hours (and the platter turning) as a computer records the speed. The results will get plotted and tell us how stable this analog system is.

Here is the speed test start.

While that runs I can write this blog post about the project :)

Another item that may be on the restoration task is the Beogram phono cable. This Type 5513 came with a five pin DIN plug so an adapter is necessary when using the turntable with a non-B&O preamplifier. The original DIN plug looks okay.  We often install a new one so that is an option here. Some people will never be using their Beogram with an amplifier that supports the DIN plug so another option is to install a new phono cable that has RCA jacks.

On this particular Beogram the correct adapter for the DIN plug to RCA plugs must have been lost. This picture shows it being used with the DIN 5 to tape deck RCA plug adapter.

Tomorrow sometime will have the results of the platter motor test and we will go from there.