"My Chrono Report"
A Chronograph is a watch that incorporates an additional watch to time intervals/ events. The mechanisms are far complex than putting & merged 2 movements into one. I am certain many ST19 powered watch brands are either lack of proper adjustments or totally way off missing all the marks.
This is the long checklist that I will go through for every PerpetuaL chronograph I make/ assemble :
An amplitude of a watch is like the engine torque in cars' engines, should be in the range of 250-320 (unit in degrees read by TimeGrapher). A chrono can appear to be running normal while the amplitude is badly affected once the chrono function is deployed. The amplitude is compromised while the coupling wheel transmits power to drive the chrono (centered) seconds wheel. In worse cases the chrono function stops from a short period to just a few hours. When a watch is fully wound & deploying the chrono function that will slightly affect & reduce the amplitude & power reserve, the watch & the chrono function should run properly up to at least 42 hours or more.
The ST19 series has got 48 hours power reserve (PR). When the chrono function is deployed continuously, it will affect & reduce the total PR by just one to a a few hours. When the watch is approaching low PR level (6 hours remaining or less) the power/ torque is no longer strong enough to drive the chrono seconds wheel & it will drag the watch to stop running. The comparison of ST19 to the major Swiss chrono movements, Valjoux/ Lemania/ Piguet, they will behave more or less the same as a result of decrease in torque/ energy level.
In cases of poorly adjusted ST19 or no adjustment at all, the watches with deployed chrono function can stop in 36 hours or even shorter time.
The running behaviors of the chrono seconds & watch's seconds hands, if not observed closely, could actually be running in a smooth (sweeping back & for motion) manner rather more like jumping & hopping. Again it comes down to the adjustment issues or lack of any, straight from the factory/ movement supplier. In many cases, my own experience is alarmingly, less than 50% of the seagull factory supplied/ acquired AAA ST19 are decently & well-adjusted. For an absolute certainty of performance, each & every single ST19 must be checked thoroughly.
The minute register, the advancement is achieved by a transmitting wheel which is commanded by the chrono seconds wheel, to move one increment (step) at one minute's interval. The ST19 will require fine adjustment for the register to advance correctly & precisely. The minute register's hand must advance correctly when the chrono seconds hand passes the 12hr mark. Sad to know many ST19 powered chronos' owners don't realize or don't even care if their chronos' minute register's hand does in fact advance at the wrong moments, too soon or too late.
It is easy to check if a chrono's hands are set correctly & precisely or not. A detailed visual check, with a loupe, the chrono (center) seconds hand must sit right at the 12 hr mark, no leaning even a bit to the left nor the right. At all times, both the chrono seconds & the register's hands must always return back to the their original positions precisely, not to the left nor the right.
A professional's strict & difficult setting tasks must be performed to ST19's hammer & 2x heart-shaped (seconds & minute) wheels for the absolute certainty. Many ST19 are definitely not in proper condition, regardless they are marked "AAA" or you paid "AAA" price, the day they leave the TianJin seagull production plant.
In order to make that many movements everyday in seagull factory, I have always found more than usual number of not up-to-standard AAA ST19 acquired from TsinLien seagull Hong Kong branch. I always pay AAA price for the AAA seagull movements, I wonder if it does make any difference at all !
The chrono's settings of the chrono's seconds wheel, the minute register wheel & the hammer are not always built correctly. In some weird cases, the heart-shaped wheels, mostly the minute register wheel sinc eit's easier to be manipulated, are altered very slightly (leaned to the left or right) in order to be better & properly struck by the hammer thus to achieve on the surface (only) that the wheels seem to be aligned & set correctly. These kinds of manipulations will lead to a faulty minute register's registrations/ indications, could be losing from a few minutes (or more) in just one hour or longer intervals. Not many watch fans realize this rarely discussed problem (if their chronos have got such fault) unless the chrono's registration is being checked on purpose by another chrono timer.
One last check before my chronos are ready to depart to my customers. The chrono must be able to start to run on its own after just a few crown's turns fro 3, 5 to the most up to 10 turns (maximum), rubs of thumb & finger motion not a complete 360 revolution. If more turns are required to get the watch running (no shaking please) this is not a sign : balance wheel, the escapement or the movement issues.
