October 18, 2008

LEDs for Lamps

I dug into the 280 quad envelope generator's indicators. Originally, Buchla used lamps for the indicators on his modules. This evolved into the use of LEDs in later and current modules. Don couldn't decide how to mount LEDs either, some modules had them mounted to a "motherboard" PCB, some had them mounted to terminal strips bolted on the panel. The owner of this 280 decided to have me replace the lamps with LEDs, so they would be faster as well as last longer. I decided to change all four, even though only two were blown.

The offending lamps are sealed into a panel mounted enclosure that was intended to be disposable. Sadly, 40 years have passed since they were installed and they are no longer being manufactured. The only solution that will keep the aesthetic of the panel is to cut off the back of the enclosure and put a new light inside it. This is the cute lamp that was inside.

Luckily, a 5mm LED fits inside perfectly. I have chosen to use RED diffused type. They light up nicely with no extra resistor! Here is the job partially finished. The sawed off lamp on the left and an unaltered one on the right.

And here all done.

I forgot to snap a picture of the LEDs lighting up, but they look great. Now the fast, "blip" type envelopes can be seen, which was not the case with the original lamps.


Peake said...

Part of the appeal to me of the early 200 modules is the mad scientist light show put on by a 212 or equivalent era modules with lamps. The tiny LEDs on the later modules are nice and precise, but not so WTF!

Looks like I picked the wrong week to quit taking drugs ;)

Jameson said...

Wow! this is pretty nice, I already create LED lamp too and I got a wonderful output. Thanks for sharing your post, it is really informational.

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