Seiko 7A38 - by the numbers

Really, that was one of the tools needed.


After my flurry of purchases over the last week, my 7T32-7A99 had failed to turn up.  MLK national holiday delayed it further and then today, it was not on the mail van.  Nice postie lady came into my den and looked at the tracking number.  Yep, should be here, but you can call the PO.  They were fed up with the day and didn't want to know.  Ten minutes later there was a hooting outside.  She'd found my box. 

Strange watch.  A mixture of okay-ish, and having been flailed in a combined harvester.  Fortunately, mostly on the crystal - the bezel having suffered rather less, I would guess only due to the height of the glass!  Most odd.

Will it go?  Stopwatch button solid - really solid.  Back, welded on.  Never did I think it would defeat my homemade crowbar,* but it did.  I have rubber jaws for the garage vice, but still to no avail.  I wanted to know if it would go.

I drilled two holes in my garage bench - an old kitchen work-surface - and cut two bars of stainless rod c 6mm in diameter.  This is where the four-pounder comes in.  The rods are now really tight in the 20mm thick surface and what's more I can bear down on the crowbar with no . . . not much fear of slipping.  I'd learned just how much force it takes to put a crystal in, so I wasn't worried about the pressure.  It took an almost unbelievable force to move it, even with the case warm and the back cooled.  Finally, it came undone.  Inside, it looked incredibly clean.  Outside, one could grow a fine crop of potatoes in the mulch. 

I read that one can take the battery out without relieving the contact pressure.  I didn't like that, but it seems one has to take the entire back plate off to effect the release.  I took great care not to bend the leaf spring contacts into the plastic range - by being aware of certain physiological processes that I can't describe on a family forum.  It's a sensory skill learned in one's yoof. 

The battery was a Seiko, and I was getting the feeling the watch had never been opened.  Only now do I find the battery is different from the 7A series, but I have one that reads 1.38 off load.  It'll have to do.  To my astonishment, the second had started to tick once every two seconds.  Fair enough.  The alarm does various things I don't yet understand, and the stopwatch was un-checkable due to the solid pusher.  It seems to be keeping good time, and the date has changed in the last hour.  Partial success. 

Now I have to check the crystal is the same as the 7A** series - 32.5mm X 1.5 mm, and get the order in for several more crystals, gaskets and batteries. 

The other parallel project is still unresolved.  Most of my hobby time today was spent ordering macro devices from Hong Kong.  The big river site needed two sources, and the carriage was doubled.  From Hong Kong, free, and on its way in two hours.

Two AM again.  Hard to sleep when you're having so much fun.

280mm long and cut to bite.  Yes, I'll get a three pronged one real soon.

I cannot describe the palpitations I suffered reading the title of this thread, only to suffer a nearly heart attack skimming rapidly through the text catching "drilled two holes" and "homemade crowbar"... and finally arriving to the image you posted and understanding what you have meant the whole time... Titles including "4lb hammer" should be forbidden on a watch forum! 

Just kidding!  But seriously, I was suffering for that poor 7T32... considering also that you can buy a case opener for a few bucks on eBay, that offers a farther nicer grip - and having 3 points of contact with the base, much more force to be applied to the case back.

As per the battery replacement, I suggest you remove the battery holder plate if you are still working on it inside the case. It makes it easier to remove the old battery and place the new one. BTW, the fact that the seconds hand moves once every 2 seconds means that the new battery is also dead. That is a function of this movement. This could also cause the strange behaviour of the alarm, but I doubt it. Check the small golden buzzer lead terminal which should make contact with the inside of the back cover. The terminal protrudes upwards from the movement, so it is easy to find.

In case you have a 7T32B movement:

A 7T32A movement looks slightly different:

Either case, you should remove the battery clamp.

Mine's the B.  Still cased and keeping good time.  The battery was in a 7A** I purchased, so turned out to be lucky after all.  It'll tide me over until the new ones come.

I should have waited until the UK awoke from its slumbers before proceeding - I had assumed one had to remove the back surface but I followed some bod I found on google and eased it out.  I didn't have an issue with shorting the battery when it was being removed.  The new(er) one I had to put slips of paper in to insulate the negative surface.  Total pain.  Now I know I can remove the plate without lots of little parts falling out it'll be much easier.

Talking of shorting.  The reset procedure is odd.  The shorting point is clearly visable but the wording is 'To the Positive side of the Battery.'  Why?   The entire back is at the same potential, and shorting the print contact to the frame with a needle is the same, surely?  It's certainly much easier.

Time to face up to the fact I'll have to remove the bezel.  The watch is so ingrained with grot I don't think I can clean it with the outer plastic ring (like the tachy ring) in situ.  Thinks . . . does the 7T follow the same rules?  As one who was just getting a feel for the design of the 7A series, this sideways leap is like starting again.

Off to the bench to play while a dozen jobs on the house get left. 

If I were you, I'd replace ASAP that battery for a proper one. 7TXX and 7AXX movements use different batteries, and until you have not got the correct one installed, do not use a wrong battery on the watch. Apart from the difference in dimensions, batteries may have a different V output. And even if they don't the difference in dimensions can damage either the lead or the battery compartment.

As per the shorting, it should be done with a pari of metal tweezers, shorting the "short lead" and the positive side of the battery, for a few seconds (not more than 5, in my experience). This is the proper procedure, as per the manual, and I believe it is also the best way to do it.

Check out my threads on the 7TXX watches I disassembled, in some I also posted a video or two on Youtube.

Let me know if I can help any further.

Thanks for your help.  Don't worry, the battery is the correct one! Erm, I hope.  The one that came out and that I assumed was the original, is a SR 927 W made by Seiko.  It says 1.55v on the Seiko package. 

The dealer that sent one of my watches put an equivilant into a 7A** - perhaps just to save getting the correct (thicker) one.  The diameter measures the same.

Talking of which, the darn crystal does not.    I had hoped to stockpile a few of them to cover both types of watch, but now I'll have to order two diameters.  The one I've just taken out measures 31.97 X 1.58   It has a polished bevel on the outside and a matt bevel on the inner edge.  I think I've read on this forum that this is a Seiko product.  I'm about to search for the nearsest from Esslinger here in the US, though I doubt I'm going to get the exact diameter from their range. 

The watch is cleaning up very well, but I'm not sure what the finish is really made of.  It's base metal with a gold coloured finish, and I find it's in better condition than my gold plated one.  The strap has polished wear, but the watch seems free of that. 

The probelm I'm having is that this is a much bigger forum than it at first seems.  There's a great deal of data here but I forget where I've seen it.  Just a case of getting to know all the streets in a new home town.   Not helped by having an old brain.

Rob, the glass varies from model to model... the Seiko 7T32-7A99 uses a Seiko inorganic glass, part no.320W40GN00, there should be a Sternkreuz alternative, whose part number should be XMF320.927, if I am not wrong. Paul is more expert than me in this.

You can find all info (as well as part numbers) here:

http://service.seiko.com.au/pls/seiko/f?p=104:21:3108243972103794::NO::P21_CALIBRE,P21_CASE_NO,P21_ITEM_CODE:7T32%2C7A99%2CSDW134J0

The case is SGPWR, Steel Gold Plated, Water resistant.

Thanks for the info.  When I get back 'home' I shall no doubt be following others in using Sternkreuz crystal.  Right now, I'm kind of lost in the US.  Googling Sternkreuz produced very few US outlets for non professionals.  The glass I'm getting now is beveled on both sides and less than two quid.  The one I put in my own watch took incredible pressure due to a gasket that will have to be changed in the not too distant future, so not too frail.  

The case on my first purchase in recent times*, a gold plated 7A38-7000 clearly shows 'sgp  stainless steel back' whereas this one just shows 'base metal stainless steel back'.  It looks like gold plate and has tolerated some rough treatment, so I'd like to know just what the gilding process is. 

This project will have to go on hold while I await the crystal, but there's plenty to do with the missing 'tick pulse' on project 3.

Gosh, I haven't used that term since fettling IBM XTs in the early 80s.  Strange to think Seiko were using their chip way back then.

.

*I purchased my 7A38-7000 stainless in 1985

A quick note about the finish.  It really is very good.  Polished with a light oxydization remover, experimenting carefully at first, the rag turns black-ish.  Not as black as with silver, but heading that way.  At no point on the case or pusher buttons can I see a hint of going through the finish.  Not so on the strap, I'm afraid, but it looks in keeping with the age and polishing didn't seem to make things worse.

I feel, like antiques, a modicum of wear makes the watch take on a more 'real' appearance.  The opposite of new glitz, or should I say, bling.

Cleaning the pusher buttons was very tricky, I didn't want to send them flying across the room with the 1" wheel.  Trying to do them by hand proved difficult, they're just not as substantial as the 7A series and I was concerned I'd bend the stem if I held them in a screwdriver handle.

When the macro kit turns up I'll get some photos posted. 

Great, looking forward to see the pictures

My macro stuff is being held in customs up north.  Knew there'd be a catch to Hong Kong quick dispatch.

Last night I set about this project and much to my relief the crystal fitted despite being 0.04 too big.  I found a way to turn the 0 - 60 scale after the watch was in.  A while back I cut a large needle to be a chisel and clamped it in a screwdriver handle.  It has been incredibly usefull for lots of tasks and I found it just fitted into a tiny gap and stabbed the brown plastic enough to turn it.. 

  This time I took the cover off (Two screws? One description said three, but no hole for a missing one.) I found it difficult to keep the battery down while putting the cover on, I think next time I'll just loosten it. 

That shorting thing I was on about.  I shorted the cover to the AC? point and nothing happened.  I jumpered it with a wire to the battery and it worked.  There should be no difference, but that's what the book says.  Mmmm . . .

I looked at the Seiko PDF and then at the clarkson site (thanks) and the latter clarified the issue of the alarm's first click.  The stopwatch function works and I'll know in a day or so if the dates continue to change.  Going back to the alarm.  Oh, my!  It's right on my hearing dead spot and would be of no use to me at all.  But, it works.  (Phew!)

Resetting the processor.  Another thing I learned last night.  Didn't need it on this one, but it made the stopwatch on another one work for the first time.

I'll pop some photos on of the finished job when I do the sales shots.  Yes, I will be selling it, despite it being a very nice design, I'm going to stick to the 7A** range.  Working on these would be quite beyond me.  Mmm . . . I do have two and a half other 7T**s - if you can call the lovely salesman's case and band I purchased a half.  Perhaps I'll get to like them and certainly this one looks very evening dressy, now that you can see past what was a bewilderingly scarred crystal. 

Glad my website (www.clarkson.it) was useful

As per this 7T, are you really going to sell it? mm interesting...

It's polished up beautifully, though the band has worn high spots on one side.  Strangely, they just look like glinting gold unless you look carefully.  The old crystal had masses of lines in it and some of this abuse carried over to the very top of the bezel.  Other than that, the case is incredibly good.  Hope I can get some photos today, though they'll only be with the 18 - 200 lens.

Over to a new "Estate Used" 7B32-7B30 thread.