Wondering what these parts are... - Page 1
Forum section: electronics / beginners

author: chipwitch
author_rank: Frequent Contributor
timestamp: April 25, 2014, 12:29:12 pm
content: Old printers, scanners and fax machines are loaded with interesting parts. I've harvested, cataloged and stored lots of parts and even boards (power supplies) in addition to learning a great deal about construction/design methods of electro-mechanical devices. The last batch of machines produced the parts in the attached images. I'm hoping someone can help me identify them.1) The black box in the lower center of the board is the part in question. I can see no way to remove the cover. My guess is any release mechanism or parting lines are obfuscated by the substrate. I should have attached a better (oblique) photo, but the only advantage would be to illustrate the lighter, gray rectangle to the right of the topside image. That rectangle appears to be a current sensor; basically a cube with a concentric, cubical hole with something passing through it. I want to say it's a relay, but on the back of the pcb, in addition to the larger terminals with a footprint resembling a relay, there are numerous traces and smaller terminals. I haven't seen a relay with a current sensor and so many terminals, so if anyone can shed some light on this, I'd be most appreciative.2) Harvested from a laser Fax Machine. IIRC, the part was located in the center of the printer under the paper track near the corona wire or maybe the laser.3) Pretty much the same location from a laser printer. Temperature sensor?4) Harvested from a laser printer. The black head was simply protruding through a panel into the paper track area; what would equate to the paper's edge as it passed through the printer. It's placement would indicate it's a sensor of some kind. I tested it with one of those cheap LCR/diode/transistor testers. It indicates it's a resistor with a value of about 3400 ohms. The black coating is shiny and reminds me of IR phototransistor coatings (glossy, dark, translucent?). I saw nothing like an LED across from it. Perhaps sensing light from the laser? If so, it's placement would suggest it was detecting ambient light as it's a relatively open section of the printer.5) Location: mid-laser printer, near the rollers. Temperature sensor? Thermocouple?

author: N2IXK
author_rank: Frequent Contributor
timestamp: April 25, 2014, 01:03:42 pm
content: Black box---potted high voltage transformer. Likely has internal rectifier/multiplier. Provided HV for the corona wire.#2--Thermal switch. Opens (or closes) when temperature rating exceeded. Resets itself when cooled. Probably used to cycle the fuser roller heater on and off.#3--Thermal cutout (Thermal fuse). Opens permanently once temperature rating is exceeded. Used as a safety device in case #2 failed closed.#4--Thermistor. Varies resistance based on temperature.#5--no idea.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 25, 2014, 01:29:23 pm
content: 5 looks like a temp sensor on a leaf spring designed to hold it in contact with a roller or something

author: N2IXK
author_rank: Frequent Contributor
timestamp: June 02, 2014, 11:00:17 pm
content: Perhaps a thinfilm RTD or similar? Hotwire airflow sensor?