Beocord 9000: Ready for Bench Testing

This weekend I completed the seven segment display rework. I didn't run into any problems with the LEDs during the twenty-four hour burn-in test. After re-assembly of the display I checked the LEDs again. My test jig has two sections for testing the Beocord display. The one shown on the left runs tests with every LED illuminated. The section on the right is when I want to check one LED channel at a time. Or I can check just one LED at a time if I move some jumpers.

During the individual display test I noticed there was a little bit of LED bleed through from the middle "dot" LEDs into the adjacent segments. This would be a noticeable thing when the Beocord is in standby mode.

I checked that all of the SMD LED components were centered in the light guide. The base of the guide was not resting on any part of the LED. Then I remembered this board has three trace repairs. The thin repair wire must be preventing a perfect mating of the light guide base to the board. To fix this I applied a thin coat of black automotive weatherstrip adhesive to the bottom (base) of the light guide. I made sure no adhesive could get into the LED slots. This was also a good thing because the three, white, plastic mounting pegs of the light guide had to be cut away to dis-assemble the display. This adhesive would now block bleed through light at the base as well as attach the light guide to the base. I apologize for not having any pictures of this step but the adhesive has too short of a working time to allow for stopping and taking photographs.

The result worked very well although the short work time of the adhesive made for some assembly stress on the repairman. To prevent any LED light bleed through anywhere else on the assembly I taped up the back as Beolover does on his display repairs. For the outer sides of the light guide though I added a coat of black 1-Shot enamel paint.

The final step was the mounting of the red display cap. I used black hot glue to secure the cap to the rest of the display.

Here is the result.

At the lower right of the picture above you can see the Beocord's lithium battery. That supplies offline power to save any cassette calibrations the user has stored in the Beocord. The battery is soldered to the board via a couple of solder tabs so it requires de-soldering and soldering to change. This battery measured okay but it is a good idea to change the battery install to use a battery holder. That makes changing the battery a much simpler job in the future and no worries about a battery explosion (when de-soldering).
Here is the reworked Beocord battery.

Now I can button up the Beocord and move it over to the test bench. I might still have some tweaks on the Beocord before I send it back to its owner but we'll see what comes up during testing.

This frees up my workbench so I can now start on the Beocord's master...as in Beomaster 8000. That will be the next step in this restoration work. I will do a quick check of the pre-restoration state of the electronics. Then I will start in on the work.