High amplitude, losing 1000+ seconds per day

[pent]

Sorry if this is a newbie question, I looked through the forums for this very topic, but couldn't find anything.  I have a ladies ST550 movement (very tiny) that I just cleaned, oiled, and serviced.  It was running pretty well when I got it, but now the timegrapher is giving me some interesting results.

Beat error was 4.2 ms, I corrected that to 0.1 easily.  Amplitude is about 240 which for this vintage should be quite good.  However, the grapher is showing more than -1000 seconds lost per day even with the timing pin at the extreme to shorten the balance spring.  Moving the timing pin in any direction changes nothing.  Balance spring is perfect, no bends, nice and flat.  All pivots on all wheels and balance staff look perfect under the scope.  No side shake on the barrel and all other end and side shakes look reasonable.  I'm really at a loss to begin troubleshooting the massive loss in time when other indicators look good.

I'm usually pretty good with fault finding and correction, but this one has me baffled.  I did nothing to the balance complete except to clean it, but no amount of timing adjustment seems to change the loss.  Ideas for this newbie who's stumped?

[JohnR725]

it would help if we got a picture of the timing machine results. So does it do it dial-up dial down and maybe one crown down position does anything change at all?

2 hours ago, pent said:

ladies ST550

it would help to have a picture of the watch so we know what we're talking about.

 

[HectorLooi]

Usually problems with the hairspring result in low amplitude and faster rates.

You say that adjusting the regulator doesn't change anything, which leads me to suspect that the hairspring has slipped out of the regulator. Check if this is the reason. And John says, we relish photos.

[ManSkirtBrew]

15 hours ago, pent said:

I have a ladies ST550 movement

I can't find any info on this movement. Who is the manufacturer? And as others have commented: pictures, please!

 

15 hours ago, pent said:

Beat error was 4.2 ms, I corrected that to 0.1 easily.

I'm going to assume "easily" means the balance has a movable hairspring stud, yes? You didn't have to rotate the hairspring collet on the balance staff?

 

15 hours ago, pent said:

Amplitude is about 240 which for this vintage should be quite good.  However, the grapher is showing more than -1000 seconds lost per day even with the timing pin at the extreme to shorten the balance spring.  Moving the timing pin in any direction changes nothing.

For me, this would suggest the timegrapher is confused by the sounds it's hearing and not giving you correct information. Here are the questions I'm asking myself if I'm the one troubleshooting this:

• Did you take an initial timegrapher reading, and was it giving a reasonable number for gain/loss per day?
• What kind of timegrapher are you using?
• What does the timegrapher readout look like? Straight lines? Snow globe? Wavy gravy?

After that, I'd be looking at anything that could be causing noise that would confuse the timegrapher. Things like the hairspring rubbing on the balance cock or wheel. The balance wheel wobbling and contacting one of the train wheels. Overbanking. Etc.

There's a great document that gets shared around for interpreting the results. Let me see if I can find it...

Witschi Training Course.pdf

Edited August 7, 2023 by ManSkirtBrew
Grammar

[pent]

The manufacturer is Standard Time, which I think was an off-brand of Hamilton, but I can't find hardly any information on it.  It does have a movable stud so that beat error was easy.  Initial readings before disassembly looked reasonable, maybe a 10s/day loss.

I attached a pic of the movement and Weishi timegrapher output.  I don't have a macro lens or microscope camera at the moment, so it probably looks a little small and blurry--sorry about that.  The movement is smaller than my thumbnail.  Thanks for the document!

[JohnR725]

8 hours ago, pent said:

manufacturer is Standard Time

found a tiny bit parts exist well sort of

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=STA_550A

then in the bestfit book we get this image

basically it's part of the Swiss movements except I don't think it is anymore. If you look at the parts list up above and you look descriptions plus look at the balance completes notice Seiko comes up. Plus the balance jewel assembly looks more like Japanese perhaps so I think it's an acquired brand by probably the Japanese.

then I really wanted a much better picture found one and apparently can be purchased. So now we get a much better picture and we can compared to yours at least where the stud and the regulator are they look like they're about in the right place.

https://www.ebay.com/itm/174802967828

17 hours ago, ManSkirtBrew said:

• What does the timegrapher readout look like? Straight lines? Snow globe? Wavy gravy?

After that, I'd be looking at anything that could be causing noise that would confuse the timegrapher. Things like the hairspring rubbing on the balance cock or wheel. The balance wheel wobbling and contacting one of the train wheels. Overbanking. Etc.

then the timing machine results. Usually for things to be right visually the amplitude has to agree with whatever the timing machine says. Often times on timing machines if the amplitude is superlow timing machine reads the wrong part of the waveform gives you a much happier number. Then everything on the timing machine has to be functional in other words we should see numbers and I always get suspicious of zero's for instance the making wonder if it really is zero or something else?

In the case of timing a really tiny watch getting at the fit in the movement holder can sometimes be problematic. then you really don't want to hold it in another holder to hold it in the timing machine Gazette can interfere with getting a clean signal. Because without a nice clean signal than everything becomes problematic.

8 hours ago, pent said:

Initial readings before disassembly looked reasonable, maybe a 10s/day loss.

now I'm going to assume that the graphical display looked right for the numeric readings you are seeing?

On 8/6/2023 at 4:55 PM, pent said:

look perfect under the scope

then reread all the other answers you got because everyone else gave excellent answers. Users scope to look very carefully at the balance and the hairspring. Make sure it looks flat it's in the regulator pins. Visually how does the amplitude luck yes I know that's why we got timing machine so we don't have to visually look. Also take all of the power off a look at the balance and hairspring look carefully make sure the hairspring isn't touching the regulator arms for instance.

 

[pent]

Thanks to all!  We got this one solved.

I disassembled the balance again and put it under the microscope and noticed that somehow, 1 or 2 turns of the balance spring were touching (GROAN), so I thought I must have bumped it and bent it at some point.  First, I tried demag in case they were magnetically sticking, they were not.  So I started to get ready to do some spring bending and as I loosened the eccentric (maybe wrong term, the thing you turn to allow the balance to come out away from the timing pin) by less than a hair, the spring vibrated a little.  I put it back under the microscope and to my surprise, no spring turns were touching anymore, all nice and even.

Remounted the balance in the watch and back on the timegrapher.  Minor adjustment, a Viola!  Problem solved.  The balance spring must have been caught up a tiny bit on the timing pin and the slightest turn of the eccentric let it free up.  At least that's the only explanation I have based on what happened.  Just glad I don't have to do any more balance spring bending!