Beogram 8002: Functional Restoration, Some Trouble Shooting and a Test Spin with Manfredo Fest

This post describes the functional restoration of a Beogram 8002 that I recently received from a customer in Massachusetts. My initial assessment of this unit is posted here.

For working on a Beogram 8002 it is best to completely remove all functional components from the enclosure and plug them back together on the bench. I like to do it on a 'Lazy Susan' so one can rotate the fragile setup without pulling wires too much:

As usual with the 8002 I started my restoration process with rebuilding the board. It is easily extracted by unplugging all the wire harnesses and the transformer block:

I removed the microprocessor can:

I could not help noticing that the single wire that makes a connection to the main PCB had broken off from the solder tab:

I re-soldered the connection and secured it with a bit of shrink tubing:

Then I replaced all the electrolytic capacitors:

Next came the decoupling capacitor in the microprocessor can:

I opened it up on both sides. This shows the component side of the board inside:

The capacitor is under the small piggybacked board:

The shield connection of the wire that was broken off on the other end had come loose inside the can:

I cleaned up the mess

and secured everything with shrink tubing:

Then I implated a new capacitor from the top side:

It is important to know that one of the leads of this capacitor also serves as a "1980s style" (;-) board via and must be soldered on both sides of the board.

I closed the microprocessor can up again and re-installed it on the main PCB:

Then I had a look inside the transformer block. I found a fuse attached to the big motor phase shift capacitor:

The fuse that was in the fuse holder was burned out:

I replaced the fuse with a new one and then removed motor capacitor, which I replaced with a new Beolover Motor Capacitor for Beogram 8000 and 8002:

This component is a modern take on the original non-polar electrolytic unit. I designed it with ceramic capacitors that are 'naturally' non-polar. A much better and durable choice than the original capacitor the basically contains two back to back connected standard polar electrolytic capacitors of double capacitance (hence the large size). My replacement part also can be used both for US 60 Hz as well as European 50 Hz Beograms by simply selecting the correct capacitance when connecting the wires.

There are a couple more electrolytic capacitors that need replacing. They are directly connected to the 5V voltage regulator that is clamped to the bottom plate of the enclosure for heat dissipation. This shows the setup as I found it:

Sadly, a couple wires had damaged insulation from previous repair efforts:

I secured the damaged wires with some shrink tubing and I installed fresh capacitors:

Then I plugged the unit in. The keypad was completely dead and there was also no dot in the 7-segment display. But light came from the tracking sensor housing:

This indicated to me that there was most likely a problem with the 5V power rail. I traced the 5V rail from the 5V regulator to the board and and then to P6 that makes all the connections to the microcontroller can. At pin 1 of this connector I measured 0.45V instead of 5V: 

This indicated that there was some unwanted resistance on the way to this pin. Indeed after going solder-point-to-solder-point with my multimeter I found a poorly repaired cracked solder point. I cleaned up the mess and soldered a wire across the damaged traces:

This restored the power connection and the deck came alive and showed the normal illuminated decimal point in the 7-segment display. I pressed start and the carriage started moving. Very good signs indeed!

Now it was time to clean the mechanical parts and lubricate them with modern synthetic lubricants. I removed the rods on which the carriage travels, as well as the threaded spindle. This liberated the carriage:

which gave me access to the screw that allows adjusting the vertical alignment of the tone arm. I adjusted it parallel to the sensor arm. This shows the carriage parts as extracted:

Lots of teflon grease! Not sure why I find so much teflon grease in Beograms when I restore them. In my opinion it is the least suitable lubricant for these delicate devices! 

Luckily there are ultrasonic cleaners that can clean such messes quickly! This shows the nice and shiny parts after the clean:

I also cleaned the teflon mess from the underside of the carriage:

And then I reassembled everything:

I also installed a new Beolover Carriage Belt for Beogram 8000 and 8002:

It is a good idea also replacing the output relay. They are often oxidized. This shows the setup inside the DIN7 jack assembly. The relay is under the clamped on cover:

I pried the cover off with a screwdriver, which revealed the original relay:

I implanted a new modern encapsulated Output Relay for Beogram 8002:

The new relay has a similar width like the original one and the shield still fits as before:

The Beogram 8002 often has hum issues when it is connected to phono inputs of amplifiers. Connecting system and signal grounds normally quenches the hum. I usually install a switch (red) that allows easily making this connection when necessary:

The next step was replacing the light bulb in the << and >> buttons assembly. The Beogram 8000/8002 models have a nifty mechanism that allows variation of scanning speed of the carriage depending on how strongly the buttons are pressed. This functionality is achieved by a mechanism where the buttons drive apertures into the light path between a bulb and photo resistors. The less light falls on the resistors the faster the carriage moves. This setup is inside the black box on the backside of the keypad:

In order to be able to work on this the PCB has to be removed from the actual keypad. Unfortunately, the person working on this Beogram before me did not seem to know that the board can slide out to the side, and so a couple of the flimsy plastic clips broke off during his "learning process" and correction was attempted by using some gunky adhesive. Not very Beolovely:

I cleaned up the mess as best as I could and slid the keypad out. Then I removed the plastic cover. This revealed the light bulb and the photo sensors. The button-activated apertures are the metal strips right in front of the photo resistors:

I removed the bulb and prepared a white 5 mm LED by sanding it a bit to ensure even diffusion of the light. I also Dremeled the bottom lip off since the bulb is exactly 5 mm, while the lip on such LEDs is a bit wider than that:

This shows the LED installed:

On the backside of the PCB the current limiting resistor is visible:

It is important that it is installed in about this location. Otherwise it will interfere with sliding the PCB back onto the keypad. I re-assembled the keypad and plugged it back in and started the Beogram. After 5 min runtime, I measured the photoresistor voltages and adjusted the light intensity controlling screws in the black housing to get the manual-specified 620mV:

This is an important adjustment since the circuit uses this voltage to decide whether to lift the arm or keep playing.

After the adjustment I restored one of the cracked but still dangling plastic tabs on the back of the keypad with a dab of epoxy. I also restored the threads of the small screw that secures the PCB in place with some more epoxy:

And then it was time to enjoy this functionally restored Beogram 8002 with a first record! I selected a vinyl I recently bought: "After Hours" by Manfredo Fest. He recorded this wonderful album in 1972 for Daybreak Records. I read it was his first foray into the US market after already having made a name for himself in Brazil. Of course this album was ultrasonically cleaned on a CleanerVinyl ProXL setup before listening! 

This shows the Beogram playing the record: 

I will now play the unit for a while and if nothing else comes up it will be time to put it back into its enclosure and send it back to its owner.

Update after ~three weeks playing around 50 albums on this Beogram:

Everything seems to be working perfectly and I was not able to find any intermittent issues. So I put it back into its enclosure and played it a bit more. Here a nice photo together with a recent Blue Note re-issue of Horace Silver's "Serenade to a Soul Sister". One of my favorite and hard to find albums and when they recently re-issued it I immediately ordered it. Beolovely!:

It is time to part with this perfectly restored Beogram 8002 and send it back to its owner!..;-).

Beogram 8002: Full functional Restoration and a Test Spin with Cannonball Adderley

This post discusses the functional restoration of the Beogram 8002 that I received from a customer in California a while ago. This post discusses my initial assessment of the unit.

When I work on a Beogram 8002 or 8000 I usually extract the technical parts from the enclosure:

This makes it much easier to work on them. This unit had some mechanical issues with the carriage. The first step is always to extract the parts that guide and move the carriage for cleaning:

A 30 min run in my ultrasonic removed the original lubricants and the parts could be reinstalled. At this point I also adjusted the tone arm parallelism since it is necessary to have the carriage up for the vertical adjustment.

Next I focused on rebuilding the PCB. Often the electrolytic capacitors are out of spec or even short circuited. Another common issue are bad solder joints on the board headers. This shows the board in its original condition:

I removed the microprocessor can and replaced all the capacitors:

I also added small 'hooks' to pins 4 and 6 of P5:

They are useful for connecting a multimeter for doing the <</>> button adjustments later on.

The perhaps trickiest part of the board restoration is replacing the decoupling capacitor (C28) that stabilizes the power supply of the microcontroller. Such capacitors need to be placed close to the to be decoupled device and therefore it is located inside the can:

I opened it:

The capacitor is found after lifting up the small additional board that is inside:

This shows the solder points from the bottom:

The tricky part is that the ground lead of this capacitor is also used as a ground via, i.e. is soldered to pads on both sides of the board. 1980s technology is fun!...;-). Since there is not much space around this capacitor it needs to be destroyed for removal. I usually unsolder the 5V lead first and then pull it upright. The next step is rotating the capacitor until the ground lead breaks and it can be removed:

With a desolder pump the remaining fragment of the lead can be extracted and the pad cleaned on both sides. Installation is reverse. With a small tip solder in the ground lead on the component side and then on the solder side, followed by soldering the 5V lead:

After this operation I closed the can back up and re-installed it on the baord:

Then I reflowed all the board headers. Especially the one that connects to the transformer block is often affected by broken out solder joints, which causes intermittent power to the deck. I usually ad a bit of solder to those points to make them stronger.

The next step was replacing the output relay, which is often oxidized. It is mounted under a shield inside the DIN7 output connector assembly: 

The shield is just clamped to the relay and can be pulled up easily:

I replaced the relay with a new Omron relay with the same pinout:

Nowadays such relays are fully enclosed, which should make them last longer. The relay I used has the same lateral dimensions like the original relay, which makes it easy to put the shield back on:

In many cases there is a hum when connecting the 8002, espeically to RCA type inputs. This hum can be quenched in most cases by connecting system and signal grounds. I usually install a switch on the output assembly that allows choosing whether to connect the grounds or not. It is convenient to solder it directly to one of the big GND pads on the PCB and make the signal ground connection with a wire:

There are two more capacitors (OC1/2) that need replacement. They are directly soldered to the voltage regulators that use the floating chassis as heat sink:

This shows the new caps in place:

One more in the transformer block:

This capacitor is responsible for the phase shift necessary for the second motor phase. Since the motor runs on AC this one is a non-polar electrolytic capacitor. It can be replaced with two back to back polar units, like I did it in earlier days, or with the more modern Beolover Motor Capacitor for Beogram 8000 and 8002, which is designed based on modern SMD ceramic capacitors. Those do not care about polarity and so are the perfect choice for this application. The board is set up that it can be used in both 50 and 60 Hz configured Beogram 8000 and 8002, which need different capacitances for the proper phase shift. In this case the unit is a US 110V/60Hz unit and so I used the smaller 27u capacitance:

After closing up the transformer box I focused on replacing the light bulb that enables the pressure sensitive gradually adjustable << and >> carriage speeds with an LED. LEDs emit light in a more consistent way over time, which is important in this case since the light intensity permitted onto the photo resistors mounted on the sides of this assembly governs the carriage speed. The bulb is inside the black box on the board:

This shows the board from the bottom. From this perspective one can see the seesaw metal aperture component that is pushed down on either side with the <</>> buttons to change the amount of light on the photo resistors:

Removal of the top cover of the box reveals the light bulb and the two photo resistors:

I usually replace the bulb with a 5mm white LED that I sand a bit to diffuse its light emission:

Since LEDs run at a lower voltage than the bulb it needs a current limiting resistor, which can be conveniently added on the bottom of the assembly:

Then I plugged everything back together and adjusted the <</>> voltages by using the two hooks I soldered to P5 when I rebuilt the main PCB:

The two screws on the <</>> assembly need to be turned in or out until 620mV are achieved on the respective P5 pins.

After adjusting the tracking feedback to yield carriage movement after about 2 turns of the platter it was time to play a first record. I selected one of my all time favorites, "Somethin' Else" recorded by Cannonball Adderley together with an illustrious group of contemporaries including Miles Davis, Hank Jones, Sam Jones and Art Blakey in 1958. I currently only have the Blue Note 75th Anniversary Reissue (2014), which was (sadly) cut from digital hi-res transfers of the original analog tapes. Still sounds pretty good on this Beogram 8002 in 'service position'..;-):

The scratched hood is on its way to Beomazed, who figured out a way to transfer the original 8002 trim to new hoods from dksoundparts. Stay tuned!