Rotary Encoders - Page 1
Forum section: electronics / general

author: Flump
author_rank: Frequent Contributor
timestamp: December 15, 2014, 04:13:20 pm
content: A friend of mine has a ham radio which uses a Rotary Encoder but its started skippingbecause of it's age and needs to be replaced, but how do I workout what kind/value it is ?Radio is an Alinco DR 605Epart number in the manual is UR0015and it is also known as RH90N74E20http://www.maas-elektronik.com/Ersatzteil-UR0015-Poti-Encoder-RH90N74E20-A9077.2.htmlThere are many Encoders on ebay but I dont know which one to buy

author: DmitryL
author_rank: Regular Contributor
timestamp: December 15, 2014, 04:18:24 pm
content: Encoder of this type is very easy to disassemble, clean with IPA, lubricate with a bit of a silicone oil and assemble back. Should work as new..

author: Flump
author_rank: Frequent Contributor
timestamp: December 16, 2014, 12:54:48 am
content: Thanks DmitryL but i want to replace it as it would be around 14yrs old now.

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2014, 07:01:15 am
content: Ebay or google it and see the pinout, size, mounting and type ( probably a quadrature type with 2 pins and common) and then look for a replacement from a reputable supplier ( RS, E14 or such in the UK) that fits.

author: nixfu
author_rank: Unknown
timestamp: December 16, 2014, 08:51:41 am
content: Google that part number and you will find the data sheet for the encoder.RH90N74E20

author: Flump
author_rank: Frequent Contributor
timestamp: December 16, 2014, 10:14:44 am
content: Thanks guysI found thishttp://pdf.datasheetarchive.com/indexerfiles/Datasheet-0100/DSA00200808.pdfbut I am still not sure what kind of encoder to buy* EditI found this toohttp://www.tocos.com/local/pdf/prototype-stock-pdf/RH90N74E20%2020S,%20RY-7725.pdf

author: VK3DRB
author_rank: Super Contributor
timestamp: December 17, 2014, 11:36:27 am
content: Sometimes it is more fun to fix a device than buying a replacement especially if it is hard to get.You might want to measure the output of the encoder with an oscilloscope. If the output signals are clearly defined and suit the logic levels used, but some steps seem to be distorted at particular positions of the encoder disc, then it is likely debris in the encoding disc.If the entire signal is somewhat distorted with not enough "contrast" between the marks and spaces then it might be debris on the photointerrupter's phototransistor. If cleaning with isopropyl alcohol does not fix it, then consider replacing the photointerrupter.

author: lhaymaker
author_rank: Newbie
timestamp: August 26, 2016, 10:58:17 pm
content: What was the outcome of your fix or repair. How hard was the encoder to repair/replace? I am having problems with the encoder on the DR0605. If replaced how hard was it ti obtain the part from TOCOS or their sales?Thanks,Linc - K0ZCO

author: German_EE
author_rank: Super Contributor
timestamp: August 28, 2016, 11:25:54 am
content: There are two types of rotary encoder, mechanical and optical.The mechanical type have three connections, are easy to disassemble and clean, and it's no problem swapping between types once you figure out the connections. Get it wrong and the unit will work backwards, no smoke, just swap the wires over.Optical encoders have much higher resolution and will have more connections as the LEDs and photo detectors will all need coupling up. Pulling one apart can be tricky as one speck of dust will cause either skipping or a dead spot somewhere on the rotation. Make sure that you have the right connections because if you get it wrong you might damage something expensive.Now, which sort do you have? If it's a mechanical encoder then I agree on your decision to replace it because those contacts might be worn away by now. Optical encoders are however still worth fixing as replacements are expensive.

author: TimFox
author_rank: Super Contributor
timestamp: August 28, 2016, 09:36:53 pm
content: Good optical encoders use differential sensing (back-to-back photodiodes) for immunity against the light source dimming or getting dirty. I have seen some bad ones that used a single-ended (single phototransistor) to sense the light through the disc, that would stop working properly as the disc got dirty or the light dimmed. Check what kind your device uses.