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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...

Showing posts with label gluing. Show all posts
Showing posts with label gluing. Show all posts

Monday, June 12, 2017

Beogram 8000: Repairing The Aluminum Deck and Front Trim

It is time to clean off the old double-sided tape residue that held the Beogram aluminum deck in place and re-glue the deck down on the cabinet

These pictures show the old tape residue.






















I like to use GooGone to soften up the old tape residue where I can just scrape it off. I let the GooGone set in place on the old tape for a couple of hours. This has to be done on the chassis under deck and the underneath side of the aluminum deck panel.




 When the old residue is scraped away I clean the surfaces so they will accept the new glue.



































I have used new double-sided tape before in re-attaching these panels before but we have found the fit is better using epoxy with some #4 aluminum washers (used as spacers).  I placed them at the same attach points as the original tape.























I use thirty minute epoxy so it gives me time to apply the glue and adjust the panel correctly. I can clamp the panel down in three of the attach points but have to use some weights on the fourth.






























The gluing procedure went well but I noticed that the front trim piece of rosewood veneer was separating from the Beogram case.





















So much of the front veneer was separating that the only good solution here was to remove the veneer trim completely and clean all of the old contact cement off.































Once the trim piece and the cabinet base, where it fits, were clean I could reattach the trim piece with some new contact cement. This next picture shows the two parts clean and ready for contact cement to be applied.

Here is the cabinet with the aluminum deck and reattached trim piece.


































I also cleaned out the base of the cabinet good and applied some anti-corrosion oil on the deck hinge.






















Before adding the Beogram main components back into the cabinet I performed the service manual adjustment for the platter to arm height. The distance from the top of the arms to the surface of the platter should be 23mm. This turntable was initially at 21.9mm so it required some adjustment using screw "A" as shown in the picture here.














































Now I could move the main Beogram components into the cabinet and give them a quick test.




Very nice. Now on to the tracking force calibration and the tangential arm tracking adjustment.



Monday, May 30, 2016

Beolink 5000: Glueing the LCD Screen Back In

The Beomaster 4000 that I recently outfitted with a toroid transformer came with another Beolove challenge piggybacked into the box: A broken Beolink 5000 remote control, which had a detached LCD screen. Unfortunately this Beolink 5000 was beyond repair since the LCD screen had mechanical damage at the contacts end, probably due to a fall of the display on a hard floor or similar. 

We decided to not give up but rather try to procure a potentially fixable unit from ebay. Luckily, a few weeks ago a 'lot' of three Beolinks became available with the promise that one of them was actually still in fully working condition. My customer won the auction and had the units shipped directly to my bench. Unfortunately, it turned out that the LCD screen of the working unit also was already loose,

but it had not detached yet from its ribbon cable. Luckily, the seller had the presence to tightly wrap this unit so the screen stayed where it was during shipping and it did come alive when I put batteries into the unit:



I decided to develop a fix for glueing the display back into the remote body without breaking the very flimsy plastic foil ribbon connector that connects the LCD display to the circuit board. In fact this particular design feature seems to do in 99% of the Beolinks since it simply rips off when the screen detaches and falls out due to ageing glue. The glue seems to be the same foamy stuff they used for attaching the aluminum cover to the Beogram 8000/8002 turntables, i.e. it is no surprise that the LCD screens also pop out at this point in time.

Anyway, the task was to not kill the ribbon connector, while handling everything and cleaning the old glue out etc...It was beneficial that I had the two other units with completely detached screens to practice on. I used them to develop a 'tool set' that would allow me to do the repair with minimal mechanical stress on the ribbon connector. 

Here we go:

I opened the unit up:
Then I carefully pressed the LCD screen out of its frame and moved the PCB and screen a bit to the left to release the board from its tabs on the right. Once the two parts were liberated I supported them with a custom designed 'brace' that would stabilize them in their relative alignment:
I applied the matching top part:
And flipped the entire 'assembly' over to the right:
Now I removed the board-to-board ribbon cable from the display control board:
The two tabs left and right of the ribbon can be pulled out and then the cable comes out:
This liberated the display part allowing me to go to work on removing the glue from the display frame:
The next step was to remove the glue from the LCD. The orange part of the brace now served as support during this procedure. I had designed a screw hole into left side of the orange part that allowed me to bolt down the circuit board to make sure there was no movement between LCD and PCB to protect the ribbon:
After cleaning off the glue it was time to install some industrial strength double sided tape in the frame. I had developed two more 3D printed parts that would allow me to apply the tape and then cut it to size with precision to not impair the translucency of the screen:
and with tape applied:
Then I cut the 'window' out of the tape layers using a razor blade and a matching 3D printed part that fit exactly into the display bay from the top:
This was the end result:
after removing the tape backing
Then I reconnected the display board and flipped it over with the braces in place:
After carefully pulling out the red brace part, I pressed the display into its bay, making sure that it was aligned properly:
And then came the moment of truth! Did the ribbon cable survive this stressful operation? After putting the keypad back on and inserting the three batteries it turned out that the operation was successful. The unit came alive again!
The next step is to figure out how to repair completely detached screens...another day, more Beolove!