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8555
is that the AS base?
Hi Peter,
As usual, you are a fount of wonderful information on GP's!
If that movement is based on the AS ebauche, I think the problem might be wear in the reverser gears. I worked on a Zodiac with that movement (the Zodiac 70-72) that had a badly worn reverser gear that would flop sidewise and prevent handwinding. The automatic winding functioned as normal though.
Regardless, Peter is absolutely right that it needs some attention. Diagnosing over the internet can be an entertaining diversio, but is seldom particularly useful or likely to be acurate. 
_john
vintage GP gyromatic - some help
Hello, my name is Mark (Germany) and I am collecting watches for quite a while. Well, yesterday I received my first GP (yes, it is an ebay one!) ? it is a man?s wristwatch, clockwork shows number 423788, 39 jewels gyromatic, case (between lugs) 9073 AF. S...
Some data
Hi Mark, first of all: Congrats, you?ve got a nice one. Calibre 42.3 was introduced in about 1966 as the third gyromatic movement by GP. Measurements are 11 1/2 lines (25.6mm) width, 5.2mm heigth and equipped with a patented micro-metric adjustment device...
is that the AS base?
Hi Peter, As usual, you are a fount of wonderful information on GP's! If that movement is based on the AS ebauche, I think the problem might be wear in the reverser gears. I worked on a Zodiac with that movement (the Zodiac 70-72) that had a badly worn re...
Hmm. Let?s speak BIG pictures for themselves....
Hi John, i was in hope you would join in as i?m lacking the technical knowledge to verify possible errors in a movement (even those i have in my hands). Regarding the base/ebauche some general words: In 1956 the first gyromatic movements were based on han...
thanks Peter!
Hi Peter, I've been doing a little more research on these movements and came across references to Communaut?e Horlog?re de Pr?cision (CHP). Apparently CHP took the AS ebauche and supplied finished movements to Girard Perregaux, Doxa, Favre Leuba, Eberhard...
It?s always my pleasure
to be here and share our passion for GP. Hampel?s book "Automatic wristwatches" mention CHP, but does not refer which AS base movement was used. According to germany?s Flume sheets (equivalent to Bestfit) several parts as the balance pivot are not interch...
thank you so much Peter
Hey. I just want to know. what are the advantages of having a high frequency automatic watch? what are the differences essentially between 28,800 and 36,000? Thank you. Saludos Alberto
Mark - Perhaps you can help ?
Hello Mark - I have an identical problem - can you remember what the watch repairers said was the fault,or faulty components and how much,or how it was eventually repaired ? Thanks Alex