Featured Post

Beolover SyncDrive: DC Platter Motor Replacement for Beogram 4002 and 4004 (Type 551x and 552x)

Late Beogram 4002 and the 4004 (Types 551x and 552x), which have DC platter motors instead of the earlier synchronous AC motors usually suff...

Thursday, May 7, 2015

Beomaster 8000: Repair of a Broken Out Control Panel Lid Spring

The last Beomaster 8000 that I renovated came back to my bench after suffering shipping damage on the way home to its owner. There were some broken traces on the uProcessor board and a broken out button PCB in the control panel). After I fixed these issues and put it back together, I set out to write a proud email to the owner announcing the swift return of this Beomaster, this time double boxed. A few seconds after I hit the 'send' button, a loud crack happened and a piece of plastic ricocheted past my head. This is what I found. One of these pieces was located on the other side of my work shop:

First I did not quite understand what happened, but then I realized this part must have originated from the Beomaster that sat on the bench next to me! I looked around and found this situation on the back of the control panel lid:
The spring that opens the control panel had broken out of its plastic retainer and the lid hung limp on its hinges. No more springy opening after pressing the bar. This spring is surprisingly strong, and while the lid is closed it stores the energy needed to open the panel. This energy released creating a projectile.

First I asked around if anyone had a decent condition lid (3D printing still has 'finish issues; it is difficult to produce good lucking parts for exterior repairs), but I came up empty. So I further examined the situation and came up with a low impact strategy to fix it. Dillen of Beoworld.org advised me that the plastic bar that holds the spring mechanism can be slid out to the side of the lid. I opened the Beomaster up again and extracted the lid. Then, indeed, the part easily came out from its groove revealing that it is hollow. This opened up a route to a 3D printed fix. Here is a picture of the part that I had printed on a Stratasys uPrint printer in ABS:
I only had access to white filament, so I had to paint the part black on the visible areas. This part fits precisely into the gap in the plastic part and over the spring:

Fully inserted:

Then it was time to test the part under stress. I slid the bar back into the lid:


Then I put everything back together. Here is a view of the Beomaster from the back:

Not too bad...hardly visible, and if one does not know how it is supposed to look, one could almost think this is how it was designed. The Beomaster went back into my Beosystem 8000 to play with its old friends the Beogram 8000 and the Beocord 9000. I want to give it a few days of testing to make sure the shipping damage has been remedied in a stable way before I ship it out (this time double boxed...this experience demonstrated that an original B&O box is just not enough protection for today's shipping environment.









No comments:

Post a Comment

Comments and suggestions are welcome!