drop-in LED meter bulb PCB for Auditronics (Beede, Modutec, Urei?) VU meters (open-source / gerbers included)

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I laid this out for my friend who has an original 8-bus Auditronics Grandson 110 console. All of his VU meter bulbs are blown out because they are powered by an unregulated 24V rail, and this is a known issue with those bulbs in that console. Made these drop-in replacement PCBs allowing you to use LEDs instead of incandescent bulbs. I realized it was cheaper and would take me the same amount of time to assemble a simple PCB and drop it in rather than take apart the existing one and replace the bulbs which will inevitably blow up.

This PCB specifically fits the top-lit “three bulb” Modutec and Beede meters, but I’ve also made a separate version for the plastic housing Weston meters that are backlit with two bulbs as found in other Auditronics consoles. More on that another time.

Obviously this doesn't only need to be used in Auditronics consoles, considering plenty of other equipment uses the same Modutec or Beede meters (3.69" W x 2.82" H ish) apparently including the original LA2A and maybe other Urei products. Use this to add nice lights to your otherwise non-illuminated meter! Seeing as both the Beede and Modutec meters Auditronics used are direct footprint compatible, I bet there are other meters out there with the same dimensions.

Remove your old meter bulb PCB, drop this one in, reassemble ring terminals as they were before. Done.

There are various optional pin-header jumpers on the back for configuring polarity/position of the ring terminal lugs, a brighter or more dim light option, etc. More on that in the build doc. I initially included these pin-header jumpers just for testing / configuration purposes of *one* meter with the intent of just using soldered wire jumpers for configuration once I got it all situated.

Here is a link to a fairly complete build guide with link to order your own PCBs (not assembled), download the Gerber files, and a bill of materials: https://docs.google.com/document/d/1XnkTOWzyiUlqTK5zi7hqMG6uh5VdrVWrgBty6MUNhkE/edit?usp=drive_link

As mentioned, I made another one of these boards to replace the 327 incandescent bulbs for the completely different style back-lit Weston meters found in other Auditronics consoles and will post here.

Photos are of the "prototype" so excuse any sloppy assembly.

Auditronics 3 Bulb PCB - IMG_5715.jpegAuditronics 3 Bulb PCB - IMG_5712.jpegAuditronics 3 Bulb PCB - IMG_5713.jpeg
 

Attachments

  • Auditronics BEEDE Meter LED Replacement (3 Bulbs) v1_1 Schematic.pdf
    17.9 KB
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