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Beogram 4002: Restoration of DC Motor Video Published - Check It Out!

By popular request (really, I got quite a few emails about this!...;-), I finally completed my Beogram DC motor restoration video! It demon...

Monday, July 28, 2014

Beomaster 8000: First Look Inside

It seems the last Beomaster 8000 is now happy, and I put it back together. It went to the living room for a few weeks of testing amongst his friends the Beogram 8000 and the Beocord 9000.
Time to open up the next 8000 in line! This one is very nice on the outside, and the interior is not different. While it was opened up before (slight screwdriver mark on the glass cover - still have to see an 8000 without...it is definitely a good idea to protect this corner with some tape before opening them up...). There is also an about 15 year old cap in there (6C35 to control the 5V ripple after the voltage regulator). But whoever did it put it back together properly...all screws the right sizes, nothing missing, even the small copper damper for the control panel door release is in its proper place.

Otherwise, it is as original as it gets upon visual inspection. Also very clean. Almost no dust! Very nice! Check out this left channel output board: Almost as it were recently put in a cleaning bath:

But, appropriate for the age, two of the red electrolytic caps are cracked, indicating that a full recap is probably a good idea. The output resistors are non-browned, which makes me hopeful that it really still worked as it was advertised on ebay.

The displays are unfortunately pre-solder mask style, as is evident from the whitish epoxy boards:

We will see how the segments are when I turn it on the first time. Experience tells me that this style displays is prone to segment failure. It seems that displays with the greenish epoxy boards may be more stable over time.

Next step: As usual, I will rebuild and test the output stages before the first turn on.

Saturday, July 26, 2014

Beomaster 8000: 3D Printed Control Panel Linkage

This is the continuation of an earlier blog entry at http://beolover.blogspot.com/2014/06/beomaster-8000-3d-printed-controls-lid.html

I started reassembling the recently recapped Beomaster 8000. It was time to try out the 3D printed control panel cover linkage that I had printed a few weeks ago after finding that the original linkage had cracked and lost one of its hooks. 

I put in the 3D printed part (Makerbot II, PLA, highest density), and it worked nicely - for a few openings and closings - then it popped out at the damper. This meant that my part had a slightly too wide gap on that end, which would allow the damper arm to come loose. I redesigned the part in Inventor with a 0.2 mm smaller gap, and had it printed again. This time it worked very well. The part clicked in solidly, almost too tight. I lubricated it with Ballistol, which resulted in very smooth operation. 

I made a short YouTube video that gives some more info and shows the part installed and in action:

The STL file for the linkage is posted on my website at beolover.com:(http://beolover.weebly.com/control-panel-cover-linkage.html).