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I have gotten bit by the collecting of watches bug. I am fascinated by all the watch repair videos and find most to be very relaxing. As my collecting proceeds I was passed down a watch from my late father. Nearest I can tell its a cheaper model Benrus quartz watch. There are no identifying marks on the back and apparently it opens from the crystal side of the case. Can anyone offer any information. I'd like to know the model or time of manufacture. I'm probably not going to get it working. This is for sentimental purposes. Thank you.

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Just try a fresh battery, chances are that it will work. If it doesn't start try some quick spinning on it axis, and pulling the stem out and in. If no luck I think the back is removable to identify and replace the module. A new strap and it will be a nice watch to wear.

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The battery access hatch looks to me to be of the type that was used on electronic watches of the early seventies, perhaps late sixties. If I'm right, and it does say "Electronic" at the bottom of the dial, it probably has a movement in the ESA 9150 line. 9150, 9154, ...They are interesting in that they are battery powered but keep time via a balance wheel rather than a quartz impulse. They are often fixable, but are a bit finicky. And my experience with an ESA 9150 that I actually got running is that it run fast. This MAY be due to the battery it was designed with was in the 1.35V range, which are not longer available. At least I couldn't find one. It may also be due to something being amiss with its hairspring. (?)

Look up "ESA 9150" and/or "ESA 9154", and you'll see what they look like, and perhaps what to expect. Good luck.

 

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This is a Benrus Electronic that is an  ESA 9154 movement. My feeling is that this is what you'll find when you are able to open it up. There are magnets on the balance that sometimes attract and capture any screw that dares come loose in their vicinity. The one I got running had two screws stuck to the magnets at the balance, IIRC.

 

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    • Hello everybody, sorry for the late reply. Thank you all so much for your help and your tips. I got lucky and found a replacement wheel bridge for cheap which actually ended up being in decent condition. I decided not to do anything about the mainspring barrel pivot since I didn't have the right tools and the barrel didn't have much endshake anyhow. I am happy to report that the watch now runs great, I have regulated it to about +-10/s day which is fine by my standards. The timegrapher result looks decent as well, although beat error is around 0.6ms which could be better I suppose. Amplitude reaches over 230 quite consistently which I'm happy with also. My lighter fluid has also been replaced by balance spring cleaning solution and now the springs don't stick to themselves anymore - who would have thought. I'm super happy with this watch, it might not be worth a whole lot but it's awesome that I could restore it and it makes me wear it with pride. To me it's a genuinely good lucking watch, it'll be my daily driver for a while. Thanks again to everybody for their input! I couldn't have done the repair without your help.   Here are some images for those interested, the bracelet isn't original but I don't really mind:    
    • Balance-hairspring system is oscillator with big Q-factor. When all in the movement is OK, the rate (frequency) is verry close to the own resonant frequency of the balance-hairspring. But in some cases, the movement (with foult) will force the resonator to work on pritty different frequency, sometimes faster, and sometimes slower. When this happens, the amplitude is always weak. So, the first thing to ask is what is the amplitude. If it is more than 180 and the hairspring doesn't touch itself and anything else, then for sure it is 'short'. If the amplitude is weak, then the first thing to do is to understand why and rectify the problem. At this time no point to check timekeeping. But, if one doubts that the hairspring is not correct, then He needs to calcullate the rate of the movement, then to 'vibrate' the balance-hairspring out of the movement and to measure the free oscillations frequency (period) with timer in order to ensure that they comply with the rate. If we have pictures, then it will be easier to tell something about that wheel.
    • So much work has gone into this! Thanks again @Jon. I will go back and check my adjustments from last weekend. A few questions for you, if you don't mind. In the reset position, I can understand the problem if the gap between the hammer and the minute counter heart is too big (slide 77) but what is bad about both hammers being in contact with the cams (slide 76)? I read somewhere that Landeron recommended grease on the runner cam, but the minute counter heart should be dry. Is that so, and why? How many tads in a ligne?
    • Could you glue two pieces together for rigidity and separate after forming? 
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