bpzle 0 Posted February 19, 2011 I have a Liftmaster 1000sdr opener (screw drive). Roughly 10 years old. Yes, it's probably time to replace but I'm cheap. Problem: within 3-4 seconds of mashing the open/close button, the door reverses direction and the lights blink for 5 seconds. It's been doing this off and on for the past year or so. It was only being affected during the hottest summer months, but now it's doing it every time. Last summer it was doing it pretty bad, but I was able to spray some silicone lube into the screw drive and this instantly remedied the situation. Until now... The safety infrared beam sensors are not obstructed in anyway, and they test fine. I test them by blocking them and seeing the greed LED go out. I've pulled the cord on the door, so the opener no longer lifts the door... It still does the reverse thing. Sometimes it will slide 2/3 the way down the track before it reverses... I'm thinking an internal safety? Does it somehow sense amp draw from the motor? Is the motor just getting weak? If so, is there a pot or something than can be adjusted? I know these semi-modern openers have safeties that "sense" when the door hits an obstruction (not related to infrared sensors)... perhaps this is malfunctioning? Any ideas? Share this post Link to post Share on other sites
tomcctv 190 Posted February 19, 2011 i had the same problem. door would start to open then stop and close. took me ages to sort it . motor on and off re-adjusting arms still did it. in the end we took the track off and at each end you will see a bronze coller that the inside shaft turns in. this is greased at the factory but the grease had got hard like bubble gum over the years and the motor thinks it is a resistance on the door. we cleaned them up and filled them with vaselin. worked good after but i left west virginia 4 months later so could not tell you if its still working or not. but looking at the manual yes it has adjustments for forced drive page 25. http://www.liftmaster.com/consumerweb/pdfdocs/A2094M.PDF Share this post Link to post Share on other sites
bpzle 0 Posted February 19, 2011 ahhh... I'll take a look! Thanks Tom! Share this post Link to post Share on other sites
Birdman Adam 0 Posted February 19, 2011 Don't replace, repair!! These garage door systems are very repairable, generally built fairly well. -Could be that the starting capacitor on the motor is going bad, causing the motor to draw too much current. I believe they do have an over-current protection device built in (to sense when it is coming down on a kid). -Check for excessive friction in all joints and such, also look for any shavings! Slide the door by yourself to be sure its not the door/track. -As a side note, check the gears (mines a worm gear driving a normal gear connected to the belt), you are actually supposed to re-grease them every once in a while. Otherwise they run dry and hone each other out due to greatly increased friction. I had to install new gears because we had no idea! The kit came with a big tube of grease. Don't go spraying WD-40/Silicon/Lithium grease on the gears - they need the thick stuff the kit includes. Every year I open it up and re-apply the grease that has been pushed to the bottom/top of the drive gear back on them, this has really helped, and I see no wear accumulating. You can see the grease tube there, it can be bought separately if needed. -There are little contactors that are driven by the drive gear that tell the controller when the door is closed or open. Check that these operate properly and contact when they should. -Could the IR beams be moving when the door opens (causing it to stop)? The IR sensing should only affect door movement if the door is closing. Share this post Link to post Share on other sites
bpzle 0 Posted February 19, 2011 thanks for the help! Last night I cracked er open. I checked the cap and all gears... I popped off the belt for the screw drive, it was still doing the start/ stop thing. Motor seemed to be in good shape, not pulling excessive amps or anything. Had to be electrical... sure enough, it was those friggin IRs! Closer inspection to the read light and it was barely flickering. From more than 2 feet away it would appear solid. Wow, I felt dumb! Lol Share this post Link to post Share on other sites
Birdman Adam 0 Posted February 19, 2011 I'm always amazed how something as little as that can mess things up. Glad its working now!! Share this post Link to post Share on other sites
bpzle 0 Posted February 20, 2011 I seem to be having more and more of those this keep-it-simple-stupid moments here lately. Share this post Link to post Share on other sites
