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Saturday, January 5, 2019

Beogram 8000 Type 5613: Finishing the floating chassis components, transformer C1 replacement & cleaning the control panel

Last night I wrapped up the work on the floating chassis components.
The cleaned tangential drive components (spindle, spindle nut, rails and new bracket) were reassembled and fitted to the floating chassis.

The spindle was lubricated per the service manual. The specified lubricants are pretty similar to the Beogram 400x. That makes sense as both series of turntables have similar tangential drive mechanics.
One interesting thing on the Beogram 8000 lubrication chart I hadn't really noticed before was the entry for the lid damping grease. It calls out a product called Kilopoise. I discovered it is made by Rocol (Rocol Kilopoise 0868). I found one seller on Ebay that sells it in small samples. Most sellers offer it in a large quantity which costs quite a lot. On these 80's series of Bang & Olufsen components that used various damping controls I have been using Nyogel 767A. It isn't cheap either. So it will be interesting to compare the Nyogel to the Kilopoise.

Here is the lubrication chart from the service manual with some notations I added.

For the spindle components I have the Molykote DX, white paste and I have a very close Rocol grease (MTS 2000 instead of MTS 1000). I also have the Esso NUTO H32. Another interesting thing about this chart compared to the Beogram 400x is this chart doesn't mention coating the rails with a thin layer of the Molykote. I have found that to still be necessary on the Beogram 800x units I have restored.

Here is the tangential arm carriage as I reassembled it.
The spindle has a thin coating of the MTS 2000 and NUTO H32 mixture. The spindle bearing and rails have the Molykote DX grease.

I should also mention that there are other modern lubricants that are suitable for this and I have used other types before. My reason for finding and using the original specified lubricant products is solely out of curiosity.

The floating chassis is ready for use.

Before getting to the task of restoring the main board and the microcomputer board I decided to knock out a couple of smaller tasks.

First the replacement of the C1 capacitor for the platter drive that is located in the transformer box.
Beolover makes a nice replacement for it that fits better than the original capacitor did.

Here is the original one.

Here is the replacement. If only all of the restoration tasks were this easy.

The next item on the list is to check out the Beogram 8000 control panel. It typically needs some cleaning and I like to add a permanently wired test connector for adjusting the forward/reverse scanning LDRs.

When I looked at the back of the control panel to open it up it didn't look too bad...but once I removed the button board I found a lot of dirt. The backside of the button board often has dust but this is a little excessive for a Beogram 800x.

The top plate and the plastic buttons were cleaned up with soapy, warm water. The rest had to be wiped with a mild cleaner and some Kimtech wipes.

Once the button board was cleaned I attached the LDR test connector. The reason I have been installing these is because I kept having cases where the LDR adjustments needed to be repeated after the Beogram 800x turntables were reassembled. It is really difficult to attach measurement probes and do the adjustment when just the control panel is lifted. There isn't much room to do what is needed. The test connector allows me to easily attach a multimeter and still have access to the adjustment screws for the LDRs.

The colors of the wires I use match the color of those corresponding signals in the ribbon cable connecting the button board to the main board. That is the Beogram 800x units that have a color coded ribbon cable. Some units, including this one, have an all gray colored cable. Nevertheless I make the test connector the same on each Beogram. The adjustment procedure calls for measurements between each LDR signal and the ground wire.

Here is the reworked control panel ready for use.

Next up will be the main board and microcomputer board restoration work.

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