Garage door fix

This past weekend I went to dump a lot of the stuff I collect in my garden into the garage. It opened, I dumped all the stuff, and then, when I pressed the button on the remote to close the door, it did not close. Since the door is a bit rusty, I thought that it could be stuck. It wasn't. I tried to force some the movement, it did not move. I released it from the rail, and tried to get the carrier on the rail to move, no success. My neighbor, who is a part time mechanic in the local shop, was passing by, so I asked him, he looked at it, heard it, and suggested that the gears might be worn out. Conclusion, I probably needed a new machine to open and close the door.

So, since there was nothing to loose, I decided to open it up and check if there was something that could be blocking the mechanics of the thing.

Started to take it apart, removed the cover, the motor, a 220V asynchronous I believe (winding in the stator), looked great. Here is a picture of the machine without the cover, sorry for the quality of the pictures, goes to reinforce my disbelieve in mobile phone camera quality...

Fig. 1 - Machine with the cover out, the electronics are still in on the left, where the open cover is

I then saw the electronics compartment, which could be removed by disconnecting the cable headers, so I took it out to have a look, at least out of curiosity.

Then I started looking at it, and realized that there were 2 relays, luckily transparent, which looked a bit dirty, and started to trace how the circuit worked to control the motor.

Fig. 2 - Dirty relays, you can clearly see the sooth, and although the lower one is dirtier, the malfunctioning one was the top one

Fig. 3 - Another view. The machine was tested (geprueft) in March 1990, that is 21 years ago, I hope it will last another 21!

I replugged the electronics and pressed the buttons to see what happened. When the electronics were in the "door opening" mode, all looked well, when in the "closing door" mode, there was a lot of sparking in the relay. So I knew there was a problem there.
I ran to my favorite local electronics supplier - I am lucky to have a nice little shop literally around the corner (3 minutes on the bike) where the guys have all the necessary electronics components, and know their stuff!

So I went there, and after a discussion on the behavior of the relays, which could indicate other failures, we agreed that it could only be the burned contacts. He then disassembled the board to check the pinout, and gave me two new compatible relays!

I came home, removed the old ones, soldered in the new ones, and ran to the garage to try it out.
The result, a nice working door again!

Fig. 4 - Two old relays, one of the legs is missing, so I had to do the same to the new relays.

Fig. 5 - The PCB without the relays. The power adapter is 2x9V, so the relays are being driven at 18V instead of 24V, that might also not be good for the lifetime of the relays (me complaining about something that lasted 21 years)

Fig. 6 - The new beautiful baby blue relays in place and ready for action. Now with blue relays instead of the boring beige transparent ones, the machine looks like something from this decade! maybe I should change the green LED by a blue one to really bring it into the 21st century!

I then decided to change the lock as well, since I did not know where the real key to the garage was (never used the real key since we bought the house) and if the machine would fail with the door closed, I would be in trouble. So that included a late minute run on the bike again to another nice little locksmith, which knows me by now, and always has the right supplies! Of that fix I did not take any pictures...sorry...

I was very proud of my fix, finally the electronics practice with the little projects around the house payed off! 11 euro to fix the garage opener, instead of a new expensive one! Furthermore, I now found the user manual of the machine, a Marantec 100 confort, which, since it is german and from the early 90's, it is complete with a circuit diagram, which enables me to build a new controller if I so wish, maybe one with JeeNodes and solid state relays for reliability (more on that when it comes to the RFID lock!)