Beomaster 8000: Updating the Displays - Preparation

The next task on the list is updating the Beomaster 8000 displays. For the big, segment displays that means replacing the original Beomaster LEDs with modern, surface mount type LEDs. It would be great to be able to leave the original LEDs  (and sometimes an owner will do that), but eventually those LEDs fail. These units are thirty-five years old now. It is expensive to ship a Beomaster 8000 due to its size and weight plus it is a good idea to keep shipments (as in re-shipment) to a minimum. Lessen the chance of something bad happening in transit.

Here are the segment displays from some Beomaster 8000 units.

The first step is to get a test rig set up for these Beomaster displays. The work will be just like I did earlier on the Beocord 9000 display (...just more LEDs). You can setup a jig without load resistors and use the current limiting of the bench power supply but I want to set up my jig with individual control lines and load resistors like the Beomaster. I came close on this initial test set up but ran short of 68Ω and 82Ω resistors. I will have to add them to my next Mouser order which will probably be this week. Anyway, though not completely like I wanted, this test rig will allow me to check the reworked display boards. This picture shows the rig with a set of Beomaster 8000 displays that have all working LEDs.

Here are the individual Beomaster 8000 display pin mappings.

Now I am off replacing the LEDs with new SMD LEDs. Once that is complete I will use the test jig to run the displays for a few hours so I will know they are good. Then they will be assembled and re-installed in the display board. While the LED burn-in test is running I will be able to do the recapping of the display board and the microcomputer board.