LED display pcb RFT ULP-2

thingiverse

This remake of a PCB is based on one I purchased 30 years ago. It features a row of three LED displays, each with two digits from the VQBxx/VQExx series made by Berlin's Werk fuer Fernsehelektronik. The files include an LED cover frame and stl-file taken from my frequency counter refresh project. The mount screw holes have distances of 95x30mm, and it has posts for screws with a diameter of 5mm. However, the crappy Chinese-made Cetus3D printer did not work well again, requiring frequent advice on how to print properly. Some people believe that the Cetus3D uses Marlin Firmware, but the Up!-slicer is problematic due to excessive commands and comments at the beginning of the machine code. This leads to buffer overflow issues, causing missing strokes during prints. In some cases, no filament printed out on certain lines at the bottom. The problem can be solved by removing unnecessary comments from the code, which is not possible with the Up!-slicer. However, printing without a raft seems to cause stuttering before resuming normal printing. Do not trust the Cetus3D's slotted eyes; I've warned you. The Gerber and Excellon files are intended for milling and drilling traces on side K1 instead of K2. Do not mirror the traces again! The SVG file can be used for making the PCB using photographic techniques, but mirror the layout according to your needs. For reference, see the picture of the old PCB. Data-sheets for the VQB 26-28 are available in pictures and full-size views. The LED's have channels guiding light toward the top surface, resulting in high contrast displays with distinguishable figures. Those LED's are still popular in Germany and some European countries. Unfortunately, high-efficiency LEDs are hard to get these days, but they can be refreshed by replacing tiny SMD LEDs inside. Guide: https://www.mikrocontroller.net/topic/284082 The pin-out of VQB/VQE-LEDs allows for easy feeding of traces on a PCB, making them a signal bus. Youtuber XRC made instructional videos using 7-segment LED in multiplexed mode connected with Arduino, but he wired the signal bus by hand.