Thanks everybody for the quick answer!
Attached are two pictures of my ATO. Everything is original . Coil is original in perfect shape polarity ok. Only the glass cover was destroyed . But at the moment is not a problem. One of the pictures shows a particular of the contacts. Leverages move very freely since they have been cleaned with a special cleaner solution used in horologery. I saw several movies on yahoo on ATO restored. As you said the bracket keep the contacts in place in order that the electrical contact occurs with the right timing.
As you see in my pictures I am not able to keep the contacts close to the bracket and most of all I do no longer know the right position of the bracket with respect to the platinum pin.
Please have a look to the tips of the contacts. It looks to me of copper or brass and the thin gold is totally wear out. I am sure because technician on shops told me they kept clean the contacts with files since they saw arcing. I can find somebody to deposit gold on them.
Last the contacts present a flat surface on one site and a round surface on the other site.
Which is the right surface that goes in contact with the platinum pin?
This particular may be important. The round surface will ensure a small contact area but the current density could be higher producing arcing.
I could not remember their original orientation since the contacts were removed several times.
I could not resolve this particular from the yahoo videos
Are you able to see if the moving pin is damaged? I can make a macro picture if you think is useful. Do I need to put a new platinum tube on?
Frank I have already done the test you mention and it looks ok. I am pretty sure the trouble is in positioning the gold contacts. I am not able to have the fingers to follow the bracket. They will not stay on the bracket. I am not sure if it is because the hole got larger. If I leave the pendulum to oscillate the gold contacts make the electrical connection some time and some time not or they will stay to long time. AS you know both of them cause the pendulum to stop.
I can use a gauge from my lab to measure the distance ( 0,25 mm from platinum pin at rest position to bracket?)
Unfortunately also the instruction went lost. Do you know where I can find them?
The ATO was bought by my father during the fifty (in fact is the old version without transistor)
Looking forward for your replies I thanks you in advance for your courtesy
Francy