Beomaster 4400 (2419): Headphones Jack Restoration

I thought I was done with the Beomaster 4400, but I had completely forgotten about the jammed in 3.5 mm headphones adapter:

After removing it it looked like this:

While I was blissfully listening to some nice jazz on the public radio on this lovely Beomaster 4400, it occurred to me that there was something missing. Then it dawned on me that the receiver was lacking its headphones jack bezel. It must have been pushed in when the adapter hit something hard and then went missing after someone opened the Beomaster up to have a look. The headphones jack was also mashed in. Ruffians!:

After taking the jack out it looked like this:

I straightened the jack bracket as good as I could with my vise. In the meantime I obtained a spare bezel. This allowed me to finish up the repair:

With a straightened bracket the jack sits close enough to the bezel to hold it in place from the backside. From the front it looks like this:

Too bad that the banged-in adapter damaged the panel cutout a bit, but I guess for a more than 30 years old unit, this Beomaster is in pretty nice shape nonetheless.

Allright...looks I am finally done! All good in Beomaster land! I really started to like listening to this receiver, but now it is time to ship it back!

Beocord 9000: Repair of a Broken Out DIN-7 Jack With 3D Printed Inserts

It turned out that fixing the broken out DIN 7 jack of the Beocord 9000 that I just started to work on was easy. The part is exactly the same as they used for the Phono input of the Beomaster 8000. Last year I developed a 3D printed part that can resurrect these sockets when their flimsy tabs break off that normally prevent them from falling into their panel cutout. When the tabs break off due to the force applied while inserting a cable plug the jack gets pushed into the enclosure. Here is a picture of the broken jack:

These are the 3D printed tabs that replace the broken off parts:

I made a short video that shows how to install them and gives a demonstration of the repaired plug:

This shows the end result:

After the DIN jack was fixed and the tape drive was installed back into its spot, I finally gave this Beocord its first spin. I made a recording using the Beomaster 4400 that I restored recently, and I played back a nice mix tape of Donald Byrd tunes from the early 70s that I had recorded a while ago on my own 9000. Lovely!

However: One segment of the display does not work, 

and I also found a 'mystery piece' in the Beocord enclosure when I initially took out the drive:

The left part is the one that I found lying at the bottom of the enclosure. The right part is its counter part from the right side of the head carrier assembly. The broken part holds down the left side of the carrier, i.e. it is mandatory that it gets fixed. Otherwise, the heads might be in a non-spec position. I found out about this part in an excellent thread on Beoworld that was started by 'Sonavor' when he rebuilt one of his eight Beocords (kudos to owning that many! It appears, and this should please my wife, I still have a long way to go until my addiction reaches this level!!...;-).

Unfortunately, I was not able to find the 2.5mm bearing ball that goes along with the spring. The ball is needed to let the head carrier slide beneath the spring without generating too much friction. Luckily, I had the second ball for taking measurements and I was able to find small batches of these balls on Amazon Prime, so this may get fixed in a couple of days.

Beomaster 8000: Repair of a Broken Phono Jack with a 3D Printed Insert

The input jacks (sockets) of the Beomaster 8000 are weakly designed. They are made from a plastic that gets brittle over the years, and frequently the tabs that fix the jacks in the socket panel break off when a phono or tape plug is inserted. When that happens the jacks fall into the panel.

So far the remedy was to obtain a replacement from a carcass...a saddening thought. Beolover has a no-carcass policy! Parting out one should really be the very last resort!

Luckily, the 1980s designers of the jacks had a few looks too many at the cheap American cars that were made during this period (remember the Dodge Omni??), and that inspired them to also cheap down their design of these plugs.

To save plastic, they introduced recesses below the jack surface, which probably reduced the weight of the jacks by about 20%. It occurred to me that these recesses could be used to anchor a 3D printed insert, which would restore full functionality and get close to the original looks of the jacks. I made a brief video about the repair procedure (some pics are below):

The STL file of the inserts with printing instructions can be found on my website at www.beolover.com. I will also be happy to supply this part on request.

Here is a pic of the broken jack:

And with the 3D printed inserts in the recesses:

And after re-installing the jack together with the inserts:

It looks and feels pretty much like an original jack...there is a slight irregularity across the surface of the tabs due to the 3D printing raster. Oh well...it is never perfect! We can only strive!

Beomaster 8000: Wire Bridges on Microcomputer Board (#9) and Broken Phono Jack

Before I put the Beomaster 8000 back together for a test-drive in the living room together with his play-pals, the Beocord 9000 and the Beogram 8000, I cleaned and de-oxidized all the contacts on the microcomputer board (PCB #9), and had a look at the inner sanctum, the EMI shielded processor cans. Usually one needs to re-solder the few vias that are on this board, since they tend to be poorly soldered...clearly in the 80's the PCB technology was not that advanced, yet. Anyway, what I found in this particular Beomaster was remarkable. Someone already had put in the B&O recommended wire bridges (and then some...), and they were directly soldered to the processor pins. Unbelievable! Here is a pic:

While the soldering appears to have been carried out with some capability, I would never do it this way...the only parts of the Beomaster 8000 that are truly non-replaceable are the microcontrollers that contain proprietary coding, i.e. one would have to extract the code from a working one, if one would want to attempt replacing it with a NOS chip...

Anyway, clearly, this needs to be left as is. I could not risk to expose those rarefied microcontroller pins to another heat-cool cycle. In a way, since the chips survived this assault, this solution is probably the most reliable...several fewer spring based contacts in between the controllers and their slaves...so I decided to just replace the two electrolytic capacitors on this board and move on.

Here is a pic after putting in the caps:

The last thing that needs to get fixed in this Beomaster is a broken phono jack in the 'socket panel' that lost its tabs that prevent it from popping into the panel when trying to plug in the Beogram:

I am working on a creative solution, since not even Dillen of Beoworld.org has this part available.  He said it is rare, since it often breaks...Another day, another 3D print...;-)