Landeron 48 reset problem - stumped!

[Arthurliu82]

Hi folks,
I’m really stumped on this one. I’ve repaired several dozen landeron 48 movements, but my last 2 have had the same issue. Start chronofunction works perfect, everything goes as expected. Nice clean crisp click to the correct position of the hammer (8219). When I try to stop the chrono, the button (and hammer) get stuck. Hammer does not click to the first stop position. The hammer needs a little help, just a hair of movement to click to the right place. Once here, second push of button to reset function works fine. My best guess is that something is interfering with the hammer, preventing it from getting to just the right place to click into ‘stop’ position. I thought maybe it’s the hammer spring, but I can’t see how that could be. I’ve checked friction of the operating lever (8139), which has noticeable differences between my two subjects, but I don’t believe it’s this piece either.

Anyone encounter the same issue? What am I doing wrong because I must have missed something.

Thank you kindly!

[rogart63]

Have you changed any parts? I have noticed that some parts are different even if they are Landeron 48 .  I had the same problem but can't remember what is did to fix it? Maybe a screw in the wrong place? 

[Delgetti]

Had a similar issue on a 248. In my case the part of the fly back lever which gets into contact with the pusher was bent.

[matabog]

check the right screws are in the right places

[Arthurliu82]

Thanks all for your replies. I appreciate it.

I’ve found the solution. It turns out that the tightness of the screw for the operating lever (8139) must be very tight.  Maybe a hair tighter than you think it can or should go. Once tightened, all worked great for both watches that had the issue. I was thinking originally that there was too much friction, too much tightness in some screws, so I started loosening some, obviously with no success. Very glad to have solved this problem and to share.

re:screws in the wrong place, I learned some time back on the forums a clever trick. Put the chrono screws back in place after unscrewing and removing parts. This way, screws always in the right place. Huge time saver.

all best,

[matabog]

2 hours ago, Arthurliu82 said:

re:screws in the wrong place, I learned some time back on the forums a clever trick. Put the chrono screws back in place after unscrewing and removing parts. This way, screws always in the right place. Huge time saver.

I now realize I underestimated you a bit... sometimes being eager to help, I don't process the entire post...

I have only serviced one Landeron 48 and I learned the screws - this is an exercise I am doing - to learn what screw goes where...

...and now that I carefully read that you repaired (not serviced, repaired!) - several dozen Landeron 48's...

 

That was a weak advice... I'll try to do better next time!

But I now know where to go for Landeron advice

Edited March 7, 2019 by matabog