Beocord 5000 (4715/4716): Extraction of Drive Mechanism

Experience makes life easier! This is my second Beocord 5000 restoration, and so I further streamlined my 'tape mechanism extraction' procedure that I outlined in my earlier post about replacing the belts in these units where I also posted a YouTube video about this process. The first step is to open the unit up. This time I took the plexiglass cover off since it needs to be polished anyway. This makes it much easier to extract the tape mechanism. I also lifted the preamplifier and radio amplifier boards up, since this unit will receive a full recap. Here is a picture of the 'unfolded' unit:

Inspired by earlier comments by 'chartz' of Beoworld.org that one can leave the solenoid in the enclosure when extracting the mechanism I realized that one does not even need to loosen the solenoid fixture if one takes out the screw that holds the bottom cover of the drive in place before taking the mechanism out (I wondered last time why there are three access holes in the front of the enclosure, but did not realize the purpose at that point - live and learn...;-).

That way one does not loose any of the alignment, except for the height of the tape mechanism. This issue was tackled by putting some small dabs of white paint on the two screws that hold the mechanism up relative to the solenoid bracket. Here is a picture of the right screw, and the screw that holds the bottom cover (that is the one that sits in the square cutout of the solenoid bracket):

When I took this picture, I was still of the opinion that I needed to move the solenoid a bit forward to get the tape mechanism out, so I marked the position of the bracket relative to the enclosure at the bottom, too. But as said above, this is not necessary. All that is needed is to mark the position of the screws that hold the mechanism to the solenoid bracket (the slightly rusty screw near the center of the photo). 

So, in summary, all one needs to do to get the drive out is to take these three screws out at the front, unplug the plug that connects the heads. After driving the counter screw at the back all the way out the drive can be lifted up and unplugged from the connector at the back and taken out (this pic shows the solenoid bracket loosened - I was still in the learning process...;-):

The next step is replacing the belts.

Beomaster 6000 Quad: First Contact

I finally found a Beomaster 6000 4-Channel (2702 Model) on ebay. The usual seller description implied not working and 'have not the right cables to test'...very 'funny'. This usually means someone messed with it and was not able to get it to work. In this case my B&O addiction in combination with the rarity of this model in the US won and I put a high bid in. The exterior is not too bad, but there are a few scuffs on the metal panels and especially on the frequency dial, as well as on the plexiglass cover. Well, I figured, better learn to work on one that is not so perfect, and then get a perfect one to serve as "beolover's masterpiece"...;-). So here we go: This is how it looked out of the box:

There is not much information about the technical aspects of this Beomaster out there except an excellent thread on Beoword.org by Geoff, who heroically fixed one up and let the world know how it went. Reading this post a couple years ago immediately made want one of these beasts, and try to cut my teeth on it...;-). His issues with the output transistors suggested not to turn the Beomaster on before having had a good look inside. Here is how I opened it up:

I followed the advice on the bottom:

I removed the bolts marked B (and A...not sure why they labeled them differently, they need to come off to be able to remove the wood trim). Here we go:

The bolts have two functions: To hold the trim to the enclosure, and hold the enclosure together. this means, that at this point, the top parts of the enclosure are loose, and one needs to hold the housing together when turning the Beomaster around after this step.

The final thing to do is to remove the nut that secures the frequency dial shaft in its bearings. I was a bit confused about this. Geoff sent me some advice (thank you very much!) and I forged ahead. This shows the nut in detail:

I used flat nose pliers to turn the nut while holding the dial on the other side against the turning motion. The nut came off easily, but then I was in trouble:

The dial came out and I slowly lowered it from underneath the housing (the Beomaster was hanging over the edge of my work bench for this procedure, so I could turn the nut from above and get the dial out from below). Unfortunately, the pulley that advances the string that moves the frequency indicator tape also emerged. Here is a picture:

The pulley is the brass part, and I think it is supposed to stay on the bearing as shown here as part 158 in the service manual:

Now I turned the Beomaster around, and removed the top parts, i.e. the control panel, the plexiglass cover, and the heatsink cover (after removing the four screws on the back and the two hex (2mm head) screws that hold it near the push buttons). The control panel cover is permanently attached by wires, but can be flipped out towards the front. This shows the state of affairs after removing the panels:

This is a close up of the frequency dial area where the pulley came out:

It is obvious that this is not how it should be where the pulley is clearly still seated in the bearing (the part in the center of the picture between purple capacitor pulley and capacitor to the right). Geoff sent me this pic from his Beomaster 6000:

Obviously his pulley is in place and actually exerts some tension on the string while staying straight. Well, that is what one gets from ebay. I will need to deal with this later.

I will post more about my initial inspection in the near future.