Seiko 7A38 - by the numbers

I thought I'd give you all a laugh by asking for advice myself for a change. 

Earlier this week, I bought a stainless 7A38-7000 on eBay. I really didn't need another one in the first place.  Paid WAY too much for it, given the only average condition. I was suffering from 'Buyer's Remorse' even before it arrived.  To make matters worse, not only wasn't it in particularly good condition, but it had a couple of issues. Foolishly, I gave in to the temptation of a sizeable partial refund offered by the eBay seller, thinking I should be able to fix it myself relatively easily. Wrong on this occasion.  I should have returned it for a full refund. 

Here are re-posts of my message to the seller and his response (copied from the 7A38-7000 SAA007J model specific thread):

The watch has been fitted with a replacement crystal. I don't think I've ever seen one quite so badly fitted. It is flush with the bezel on the 6 o'clock side and nearly 1mm proud on the 12 o'clock side !! In hindsight, it's partly visible in your 6th listing photo (but worse in the metal). That probably also explains why the Tachymeter ring is mis-aligned ....

Here's the seller's eBay listing photo, that I referred to in my message:

Head on view, showing the mis-aligned Tachmeter ring (a minor detail):

Firstly (just to show I wasn't exaggerating - well not by much  )  - that badly fitted replacement crystal. 

In the first photo, it appeared to be distorted, so rather than make any further attempt to press it in properly, I (wisely in hindsight) decided to carefully press it out (with a view to re-fitting it squarely). Bearing in mind how much of the crystal was showing above the bezel, I was gobsmacked to find that it was only 1.0mm thick, instead of the correct 1.5mm I was expecting. The reason whoever had attempted to fit the replacement crystal hadn't been able to was because, when measured I found it was 32.6mm diameter (instead of 32.5mm) !  The crystal gasket had been chewed up slightly as a result of their efforts, but was still just about re-usable. I probably would have fitted a Sternkreuz MSM325 as a replacement in normal circumstances, but discretion being the better part of valour, plumped instead for a Cousins cheapie p/n F150CMH325, with the bevelled edge downwards. You wonder why I have this loathing for high street watch botchers ? 

As so to the burning issue ....

You described it as: Quartz movement, FULLY WORKING with new battery. The chronograph function does NOT work properly. Although it 'clicks', the pusher at 4 o'clock does nothing. It will not reset the chronograph hands. The only way to do that is by pulling out the crown. Nor does that pusher operate in 'the two seconds hold in' self test mode. Nothing.

I'm going to dismiss the seller's reply as bnllsh!t:

I did check the chronograph and the 4 o'clock button was a little sticky from recall but was resetting.

It's not at all sticky, though no doubt will benefit in due course from cleaning, new seal(s) and greasing. Its action isn't as crisp and positive as the 2 o'clock pusher, but you can definitely still feel that clicky-ness usually associated with this model.

Something I should have added is that when you pull the crown out to the first (setting) position, is that it's possible to advance the 1/10s and 30 minute counting sub-dial hands (using the 2 o'clock and 10 o'clock pushers), but not the central sweep second hand (using the 4 o'clock pusher). Yet when you start the chronograph, the centre second sweep hand moves sharply off it's mark. So it's not the frequently predictable setting lever (height) issue.

First thing I did (to eliminate a dodgy 4 o'clock pusher) I did was to remove the movement from the case, replace the crown stem and press the switch lever cams with a probe. Same result - no response from 4 o'clock. I then replaced the movement in the case (after I'd fitted the new replacement crystal) and checked the 7 back-plate screws for tightness. It's surpring the difference one slightly loose screw can make - only it didn't on this occasion. That would have been too easy. 

Although I wouldn't describe the movement as pristine, there was no evidence of any previous battery leakage.

Here's a few photos I've taken at various stages of partial dismantling (3 times so far):

So far I've tried swapping the respective coil and the PCB - though there's no real reason to suspect either. Made no difference.

Although I'd already satisfied myself of the cleanliness of the contacts in the 710 spacer and the 4 o'clock pusher's switch lever, I then took the unnecessary precaution of swapping them both out for NOS items. That made no difference either ! 

The  symptoms persist.  Suggestions anybody ?