What is this component? - Page 1
Forum section: electronics / beginners

author: psteichen
author_rank: Contributor
timestamp: January 19, 2016, 07:24:50 pm
content: I am trying to repair an HVAC controller on my 2003 GMC Yukon XL. It has knobs that are used to set the temperature. These knobs rotate infinitely and have a segmented feel to them with 18 detents felt during rotation (20 degrees per detent). The current part is causing the temp to advance randomly up or down as the detents are passed, instead of corresponding to the direction of rotation. Unfortunately, I don't know what to call them, so that makes finding a replacement pretty difficult. Any help would be appreciated. Photo attached (numbers visible appear to be 90 and 36...not sure if others are hidden behind the structure).

author: Zbig
author_rank: Frequent Contributor
timestamp: January 19, 2016, 07:27:21 pm
content: It's a rotary encoder. Yours has noisy contacts.

author: psteichen
author_rank: Contributor
timestamp: January 19, 2016, 07:34:50 pm
content: Quote from: Zbig on January 19, 2016, 07:27:21 pmThanks Zbig! That's mostly what I needed, but if anyone else has hints on finding a replacement (or other names for this component), that would be helpful too!

author: edpalmer42
author_rank: Super Contributor
timestamp: January 19, 2016, 07:49:13 pm
content: It certainly sounds like a rotary encoder. They come in optical and mechanical versions. If yours is a mechanical type, there's a chance that you could clean the contacts. Some disassembly might be required, but if it's unusable the way it is, there isn't much to lose. Finding a compatible replacement could be very difficult.Ed

author: Paul Price
author_rank: Super Contributor
timestamp: January 19, 2016, 10:50:17 pm
content: It is definitely a mechanical rotary encoder with a push-Sw. You can unsolder and then it is easy enough to disassemble and clean.If you can a local source for electronic switch lubricating grease, a small dab applied ensures that you will have it working trouble-free for years.Optical encoder switches are usually only used with motors and don't exhibit this type of malfunction behavior.

author: psteichen
author_rank: Contributor
timestamp: January 19, 2016, 10:58:18 pm
content: I've removed it from the PCB and can now see a few more markings. It has an icon for Matsushita (Panasonic) on the bottom as well as JPN (which I assume just means made in Japan). No complete part numbers are present. Just a few shorter numbers. Like 90 and 36 on one side, and 226 on another. I've searched DigiKey and Mouser to no avail. Apparently this part was sold to GM and not made available otherwise???

author: Paul Price
author_rank: Super Contributor
timestamp: January 19, 2016, 11:05:03 pm
content: This is from appearance a custom made switch.No problem, unbend the tabs at the bottom, it will easily pull apart.If none of the sw. contacts are physically damaged, then just clean, apply a PTFE (TEFLON) insulating grease lubricant and put it back together and you're good to go.

author: psteichen
author_rank: Contributor
timestamp: January 19, 2016, 11:12:43 pm
content: Quote from: Paul Price on January 19, 2016, 10:50:17 pmUnfortunately I broke it further while desoldering it. Are there strange types of solder that are difficult to remove with solder wick? Anyway, two of the prongs broke off, so now its either find a replacement, or just purchase a new $140 controller on Amazon.

author: Paul Price
author_rank: Super Contributor
timestamp: January 19, 2016, 11:24:02 pm
content: Farnell, Mouser, Digikey, ebay(has hundreds offered) all offer rotary encoders that will work but the length of their shaft and pinout will likely not match the original. Some jerry-rigging might be required. Think about heat-shrink tubing for coupling, a hacksaw to remove top of old shaft, epoxy.http://www.ebay.com/itm/Panasonic-Rotary-Encoder-Panasonic-EVQ-WTEF2515B-/271425927484?hash=item3f323ef93c:m:mYVOUlooks very much like the original.Solder wick can best help to remove a component like this when used with a good temperature controlled soldering handle and most importantly, applying liquid flux. The flux lowers the viscosity of the molten solder and allows the wick to quickly remove almost all the solder from the switch pins. When solder wick is used properly with flux, the component usually will almost be ready to just fall off the board.