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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...

Wednesday, October 28, 2015

Beomaster 8000: Replacing the Incandescent Indicator Light Bulbs with SMD LEDs

I always enjoy rebuilding the display board of Beomaster 8000s. So much of the signature looks of these units depends on the gorgeous large 7-segment displays and the masked indicator lights for clipping, filters, mono and manual tuning. With this particular unit I started out by replacing the indicator bulbs with my recently designed SMD LED based replacement boards. There are two versions of this board accommodating the two left and right incandescent bulb cabinets. The contact pads for the bulbs are mirrored in these compartments, while the polarity remains the same. This mirror symmetry requires different boards to accommodate polar devices like LEDs. Here is a picture of the boards that I installed:

When I developed these boards I made a video how to install them:

It is important to keep in mind that the LED boards run on a much smaller current than the light bulbs, and this requires the removal of the resistors R34/36/38 and 40 on the display board. Otherwise the LEDs will always be on.

This shows the original light bulbs in their cabinets:

And after replacement with the SMD LED boards:

And in on condition:

On to rebuilding the 7-segment displays.

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