Slave-Dor 838 garage door opener - help??

[gerrymoore]

This electric door opener was in when we bought the house 10 years ago. It has worked (with more and more manual help from me!!) but now just starts and reverses a few inches. I have disconnected it from the door and I can move the (heavy wooden) door fairly easily on its springs and rollers so don't think that's the problem.

Quick look inside the opener and it's a motor, with small pulley, belt driving a larger pully attached to the long worm drive that pushes and pulls the door. Looks to be a quite complicated PCB motor control (with a small remote control to go up or down).

I don't seem to be able to find a service manual for this so just wondering where to start fault finding - could be a relay or bad joint?? Anyone any had experience of these? ...or I can just push the door open and closed myself

 

[500e]

When disconnected does the mechanism cycle correctly

 

[voipio]

Does the motor still sound like it's running when the door stops moving? If so, it could be a sign of a slipping belt.

 

[gerrymoore]

No doesn't work when disconnected from door just goes a bit forward then backward then stops ...not a slipping belt as it is toothed and quite tight but not too tight.... Haven't had time to take it apart and give the PCB a good looking at... will try tomorrow ..thanks for suggestions though....

 

[Alan Reynolds]

Look for dry joints on the pins of any large plugs or transistors on heat sinks. There are usually a couple of potentiometers on the unit that control limits and also loading. If there are any, try a slight movement in each direction. It may be detecting a false load.

 

[Matchless]

Electric door openers make naff all on ebay, you might find the same model for £20.00....

 

[MoreWellie]

long worm drive

Before you do anything else, this long worm drive looks like it should be greased. On ours the grease dries up and causes a lot of drag so I spray it along with wd40 and the door works fine for quite a while again

maybe best to make sure there is no car under the worm drive when you do it and wear protective glasses, keep your mouth shut and walk backwards as it does tend to drip

Next is look at the arm hinges, they don't want to be too tight or too loose and oil them, ours have round plates between the arms and I oil down the side of these. I use motor oil but anything not too thin

 

[gerrymoore]

Thanks guys. I did grease the worm drive a couple of years ago and yes, it made it worse!! Don't think it's that now though. I've had a look as best I can with it in situ as it's a bit of a job to get it down I can see two long thin threaded bolts which seem to have contacts on them ..I presume these are the forward and backward 'stops'. They don't look too well though ...this might well be the cause.

It's such a job to get it all down, and the door is very easy to open manually, (and the garage is full of 'stuff' not used for the car ever) so I'm going to just leave it be and gain some new and improved bicep muscles

So thanks all for the replies and I'll close this off......

 

[Scottw]

Does anyone know where i may be able to get the drive belt for the Slave Dor 838?
thank you in advance