The Cranky Sysadmin A world of technology, fun, and ignorant rants.

October 28, 2012

How to Find Good Junk

Filed under: Electronics — Cranky Sysadmin @ 12:04 pm

I recently picked up two pieces of imaging equipment from the early nineties. My aim was to salvage parts from them. I picked up both pieces for $15, so it’s not the end of the world if I’m disappointed. One of the boxes was a “infrared imaging” system built by an engineering company. It was a rack mount device and was ugly. The other box was a “color video printer”. It looks like a piece of expensive consumer electronics.

It turns out that the quality of the parts inside were completely different. Here are some external details of the infrared imaging box

  • Aluminum and steel chassis and face plate.
  • An encoder wheel which looks robust.
  • 10 robust looking toggle switches.
  • Two line LCD display
  • A row of BNC connectors on the back.

And external details of the color video printer:

  • Thin sheet steel chassis and case with a plastic front bezel.
  • A row of RCA jacks and a toggle switch in the back. Various buttons and led’s in the front. They are built into the bezel, so it’s hard to judge quality from the outside.
  • Several plastic doors to allow access to the printer and fine tune controls.

I started with the color video printer thinking that there would be good junk inside. Well, there was but I was disappointed. The case was hard to remove. The switches and displays behind the bezel were poor quality. The only processing IC was a custom looking ASIC who’s part number didn’t reveal anything on google. There are lots of discrete components that I will probably salvage when I’m bored, but it’s going to be a tedious task. The printer has some nice motors and hardware that I’ll probably salvage, but overall, I’m glad I didn’t spend more than eight bucks on it.

The infrared imaging box was an entirely different story. The case was easy to remove, revealing good quality toggle switches, an encoder wheel which is a single part instead of bits built into a plastic housing, and a main board which is full of socketed standard looking IC’s. The BNC connectors seem to be high quality and easy to remove. The two line LCD is the same type that many Arduino enthusiasts use with the same pinout. Below is a picture of the main board, the LCD, and the encoder wheel.

Main board from an infrared imaging system

Look at all of those socketed chips. Data sheets are readily available for most of the items. The interesting components include some Altera EPLD’s (Erasable with UV light), A handful of 256k bit static ram chips which can operate at 3 volts (they still need a 5 volt supply), several 12 bit A/D and D/A converters, and a lot of 74XX TTL chips. All IC’s are socketed. Wow, jackpot!

I’ve noticed this pattern. Consumer electronics are very difficult to salvage parts from compared to equipment made for small vertical markets. This is probably because the consumer electronics companies have to spend a lot of engineering effort to squeeze pennies out of the cost of building their gadgets, whereas vertical market manufacturers can’t waste the engineering effort doing the same for a relatively small savings. I’m sure there are exceptions on both sides, but if I’m sifting through my local junk store, I’m going to gravitate toward these strange well engineered vertical market items.

No Comments »

No comments yet.

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress