A7753 Service & Analysis - The thread you've been waiting for!

[14060 or 16610?]

Great analysis, thanks for posting this.

I was wondering though why you keep the parts in the jars when using the ultrasonic. Wouldn't that restrict the flow (dampen the vibrations), thereby making the cleaning less effective?

There is indeed a loss of wave strength inside the jars. But the ultrasonic is powerful enough that it passes the tinfoil test even inside the jars, in all parts of the tank! Cavitation is very evident, and depending on what solution(s) I use I can get streams of bubbles rising as if a soft drink is being used as cleaning fluid.

Using jars helps me conserve fluid. It's easier to discard a few scant ounces versus dumping a half gallon.

 

[Drulee]

Using jars helps me conserve fluid. It's easier to discard a few scant ounces versus dumping a half gallon.

Excellent point. I assume this is also why you use an eight minute cycle instead of four??

 

[14060 or 16610?]

Reassembly was also pretty routine and on par with that of the A7750. After all, most parts are shared.

Look at these excellent analyzer results:

Now for the weak spot of the movement. Click on the video to see. Can anyone guess what the resulting problem is?



I have to sign off for now but will be back again...

 

[midasmook]

Fantastic

 

[Jonny5]

Now for the weak spot of the movement. Click on the video to see. Can anyone guess what the resulting problem is?
.

Give the watch a slight knock and the date wheel stops working?

 

[14060 or 16610?]

Give the watch a slight knock and the date wheel stops working?

Close. Actually, the problem is that the advancing gear jams up whenever you try to use the quick set date function. So it's basically useless, at least on this particular movement. I haven't seen enough of them to be sure, but I'm guessing (hoping?) the problem is specific to this one only, and hopefully other A7753s will have better fit and finish.

Thanks for the props everyone. I can really get into this stuff when time permits.

Here are some measurements, for those of you wondering about A7750 swapability (did I just invent a word?):

30.39 diameter
07.42 thickness (excludes rotor and post protrusion)
00.19 all 3 subdial posts
02.00 hour cannon
01.20 minute cannon
00.20 center chrono post

 

[xeebot]

Close. Actually, the problem is that the advancing gear jams up whenever you try to use the quick set date function. So it's basically useless, at least on this particular movement. I haven't seen enough of them to be sure, but I'm guessing (hoping?) the problem is specific to this one only, and hopefully other A7753s will have better fit and finish.

Have you seen this thread on RWG that has a detailed review of the A7753 as well? In it the OP states:

"Instead of inserting a pin to tension the quick dateset spring, they simply screwd a screw into the bottom of a threaded hole. Not very well thought out, and as I found out during assembly, a real challenge to get the spring in place, before the plate is installed."

I'm a noob, but reading that reminded me of this post. May not be related at all, just thought I'd mention it.

 

[14060 or 16610?]

Yup, saw that post shortly after mine came out. Zig does the best reviews in my opinion. Very detailed, and obviously his photo equipment blows mine away. Anyway, what he posted is not related to the problem with the gear itself. That spring is a pain, though...

 

[GBOGH]

Great info G! :thumbsup:

 

[tangle]

great thread, thanks.

Always fasinating to read and gives us novices an insight into why we should never try to service a movement, give it to the pros!

thanks

 

[14060 or 16610?]

Just wanted to update this thread. I've worked on many A7753s since, and none of them has had the problem with the date advancing wheel jamming. So the watch used in this thread was unfortunately defective.

 

[AskMeAgain]

The more I read posts like this the more I realise I wont be servicing my own movements and why you are worth every red cent charged Thank you for your work.

 

[Wiz]

Very interesting thread! Thanks for taking the time