VHS Equipment Review - Programmable Green LED Sign

[Variable]

Labelled as belonging to @RobertButterworth. Some background on this sign here.

(The three dark bars appear to be due to faulty LEDs or circuit boards, not a running demo or program.)

I’m not seeing much reason to keep it as it runs on a 25 year old 386 and uses 3.5’’ floppy disks to store programs. Redundant since we have the Raspberry Pi based multi-colour LED wall.

• Keep
• Toss

[Janet]

Rob is still around. I will ping him and send a link to this post.

[Majicj]

I think @dbynoe was working on this at one point.

[dbynoe]

Wow, just looked it up and that was two years ago… I got stalled emulating the isa bus. Then I got working on a job… like took over etc etc.

JVF 2010-A - The Space's Green LED Sign - Whats inside

So update time, first things first, gotchas: The power switch on the back switches the neutral not the hot, thus when the sign is pluged in and turned off accidently bridging things to ground is exciting. Keep this in mind when poking around Most of the custom board has latching flipflops, that latch to ground when its off. This makes it fun to figure out which are actually data lines. I have worked out most of the pinout on the 386 side and how it maps to the 31 pin ribbon cable to the…

Surprised to see the dead zones, not too sure whats going on there, might be an issue with the shift registers of the power board. I never made any modifications to the hardware, just plugged in my own ribbon cable in place of the on board 386’s

Im tempted to keep it because its a heck of a lot of leds, that can display usable text but I don’t know if I have the cycles to actually finish it off. Option b is to go the same way noisebridge did it and talk direct to the shift registers: https://www.noisebridge.net/wiki/Big_LED_Screen

[RobertButterworth]

I donated this way back. At the time all pixels were working I thought at some point we had it running at VMMF with some text displayed.