Casio AWR-320 problems

My second Casio ARW-320 has a problem. After 4 minutes the analogue module stops. 
The problem is in one of the small plastic wheels. It has a broken tooth. I've tried to put the tooth in the correct place but it was broken, so right now the ARW has a missing tooth but works :)
I'm checking the accuracy of the watch. With a missing tooth seems clear that it will loose some time. The first 2 hours it loose 2 minutes and 40 seconds, a little bit more than 30 minutes per day. It is not a good accuracy, but it works more than 4 minutes ;)
I will try to look for an old destroyed ARW-320 in order to get a good wheel.

Second Casio ARW-32'0 at home

Today I've received my second Casio ARW-320! I thought only one on my box was not enough so I've look for another one :)
This second watch is not working properly. The digital module seems to work great, but the analog module doesn't run. The second hand seems to move but it does not advance, so any other hand is moving. 
I hope a good clean of the module will solve the problem. If at the end I'm not able to solve the problem I will have a lot of spares for my working ARW-320. 
Both are the orange button version... so now I need the yellow version one :)

Casio G-Shock DW-5900

Here you are some pictures of the cleaned Casio DW-5900. 
It is the 1st G-Shock with the 3 small graphic sub-dials, released on the 1990.
This watch doesn't have light, quite strange on a G. It has 5 alarms, stopwatch and timer. As all G's it's 200m water resistant.
It is one of the classic G-Shocks, and this unit is in pretty good condition. For sure forgotten on a drawer for long time.
Not only is a special watch due to the 3 sub-dials, it is also one of the watches used on a NASA space mission. The linked picture shows this watch on the left hand of the left astronaut. 
 According to Wikipedia is a NASA Flight-Qualified watch!

Casio one of the greatest watch brand

Casio is one of the most, or the most, important digital watch brand. The company was founded on the 1946 but the main business were the electronic calculators. The first LCD watch was released on November 1974, the Casiotron (picture from Casio web site).
From this point, Casio released a lot of different watches. From the calculator watches early 80s, to the sensor watches early 90s, but also, remote control watch, radio controlled watch, solar watch, GPS watch, radio receiver and radio emitter watches, etc. It is summarized in Casios web site.
The G series started on 1993 with the DW-5000C-1A and nowadays is maybe the best known kind of Casio watches.
The F91w is the watch we all have or had. The watch that suffered the the childhood of millions of us.Today's a trendy watch that could be bought for less than 20 bucks! (Picture from Casios web site).

Design Tip - 13

This design tip is the continuation of the Design Tip 12 about the screw bosses and their sink mark problems. The previous Design Tip was one improvement to reduce the risk to have sink mark, here you are another tip to minimize the sink marks.
To minimize the sink marks, a recess around the screw boss will help to reduce the sinking mass. 
In my designs I never pay so much attention on the shape of the recess. I did them from a round half torus (doughnut) to something closer to the sketch with small radius. All designs worked well.
Some days ago reading a documentation from Lanxess, they said the angle alpha has to be 30º and the depth of the recess 0.3t. I've never used formulas to design this kind of recesses, but I suppose the design guideline given by Lanxess is due to their experience, and it seems a good design. I think next time I will use these dimensions to see what happens. The 30º angle looks nice to guide the material flow to the thinner pass, the depth seems too much for my applications, so I will reduce to 0.5mm on a 2.5mm wall, but if a big screw is needed, then the boss walls will be thicker, so 0.3t could be a good number.

Casio W 780

7

One of the last watches I have is the Casio W-780, it is a rare old classic Casio watch. There are 2 versions, the W780C from the 1987 and the W780C-1V(B) from the 1991. The retail price for both watches was 39.95USD.
The watch case is made of steel, not chrome plated plastic as modern vintage series. The watch is very heavy for its size. And Japan made, not China or Malaysia as modern vintages.
It is water resistant 100m and has stopwatch, countdown, alarm, light, date and hour.
The glass screen is scratched and quite difficult to polish, but the steel case has been polished to remove the scratches and leave the watch ready to wear (well, first of all I have to buy a band for it).