Seiko 0624,

[767Geoff]

Hello all and a happy new year

Just picked up a dead 0624, beat up with a chipped crystal. I thought I would use it for parts or a beat up working one that is on its way.

Well, I dismantled it, cleaned lots of copper sulfate (blue crud) from it, resoldered all solder joints, applied deoxit gold to the contacts after cleaning them all with a fibre glass brush. And lo and behold it works, sort of. It displays perfectly so I do have a 100% functional crisp LCD. The case is cleaned up, polished and brushed as per the original factory. Now to the problems,

The time works.
The bulb works.
The time setting button works.

When you push the light button the light lights up and will not go out when the button is released. Of course when the time set button is pulled the light switch should become the hour. minute, second selector. Instead the light circuit, now the time set circuit is always active so the time cannot be set. Pushing the time select button back in the time appears and the light is still on.

Now when I install the battery for the first time the time starts up without the light and ticks away. Pull the time select button and the seconds start to flash. I can reset them, when I move to the minutes I need to push the light/hr,min,sec button to correct the time and then it locks up, flashing away on the minutes not allowing me to set or move to the hours. I have had the watch apart 20 times and still cannot figure this out unless it is an IC problem, or maybe the capacitor (oil filled one near the quartz crystal).

So in a nutshell by pushing the light button or conversly the "hr,min,sec" time set button if in time setting mode; seems to close the circuit and will not release as it should, that is the light won't go out, or the hr,min,sec selection and time correction will not work.

So the watch is on the work bench, ticking away without the light on, but unable to set.

The second problem is the case crystal, one is severly chipped and the other in a bad need of polishing. I do not need the 0624 crystal button holder, just the crystal which I can mount onto the bezel. I remember seeing someone here that can cut crystals or has or is there a source for just the crystal or crystal attached to the inner bezel.

In a nutshell, help needed on the circuit as described above and help needed finding two good crystals for the case.

cheers, Geoff

[767Geoff]

Update!

Still need a crystal, but, the watch has been running now for the last 4 hours and it seems that the setting function has improved.

It is still buggy, but I was able to set the time, getting the hours and minute digits to change with the set button about 90% of the time. Seems the electronics are improving as it is exercised with a current. Probably hasn't been running for years.

[dutchsiberia]

Funny, my 0634 has the same problem at the moment, insert battery and the time works, press light switch and the light won't go out anymore. I haven't used it for a while, I'll see what a new battery will do.

[767Geoff]

Funny circuit. The watch is keeping perfect time with a crisp display.

In time mode:
-The right button now intermittently turns on the light.
-The left button always turns on the light.
-the light does not go out when either button is released.
-the light does go out when the setting button is pulled and the watch is then in set mode.
-it remains out when the setting button is pushed back into to time mode.

So the light is usable but can only be turned out be pulling, then pushing in the setting button.

In set mode:
-the right button occasionally selects hours,minutes, or seconds as it should.
-the right button occasionally advances the hour, minute, or reset the seconds (it shouldn't).
-the left button occasionally advances the hour, minute, or reset seconds as it should.

So it would appear the "light on off circuit" is defunct and that this circuit controls the time advancement function in setting mode. This mechanically would involve the setting button push pull setting. I know this is not the problem as the setting lever and contact spring are working perfectly. It must therefor be a corrosion related problem within the transistor or IC itself.

The manual does not describe this but does describe a light logic fault as grounds for a new circuit block.

None of this affects the time keeping capability but does make setting the watch awkward! Once set, the light can be used but must be turned off using the set button push-pull mode.

Dutch, check yours with a battery. But from absolutely dead to buggy working is still a step in the right direction. Did yours have corrosion problems? One of my concerns is the capacitor on the circuit. It 'appears' to be on the light circuit and it is oil filled. Maybe it has dried up internally and is causing the fault. The circuit manual does not describe its function.

Cheers, Geoff

[dutchsiberia]

I'll check, the watch used to work fine, but spent a long time in my cold bed room.

[767Geoff]

Now the right button in setting mode is working perfectly, in that it selects the second, hours and minutes correctly. The setting button, the left button still advances the digit by one, but then closes the circuit preventing another advance. To get around this I must push the time setting button back in, pull it out, select the hr or min digits, advance by one, redo the above. Most cumbersome! But at least this dead watch is now set able and working.

Geoff

[Seiko Kid]

All these 06 circuits have an almost identical build. can you explain more about this "oil filled" capacitor ? don't remember seeing one of those
check my posting about my 0674 issue on here for pictures

I would suggest giving it a bath as the light circuit simply runs from the battery via the up convertor ( black chip near the setting switch )
unlike the newer circuits ( m series and onwards ) where the light circuit runs through the IC
As it sounds like you have some shorting going on

[767Geoff]

Right beside the quartz crystal can is a cap on mine. I will disassemble, give it a vinegar bath and see if that fixes it. I agree, the light circuit is shorting, once pushed it stays on which affects the time advancing ability with the button when in setting mode.

Geoff

You can see the two cans here http://forum.pocketcalculatorshow.com/topic/seiko-0624-design-evolution?reply=292618760857711088 fifth photo at six o'clock. Maybe I am wrong and it is not a cap.

[Seiko Kid]

I haven't found those capacitors to be anything to do with the light circuit - not aware that they are oil filled though ? I have a load of faulty boards so I will cut one in half and report back

they should be reading approx .470 on your capacitance meter. I have found them to be a possible problem behind the LCD drive circuitry side though even on a failing circuit I am still getting the same readings

I would move away from the vinegar though, it will still leave contaminants on the board

if you get stuck and want me to test it on my oscilloscope and give it an acid bath then get in contact and send it over

[767Geoff]

Thanks seiko kid. Did an acid wash and will report back. Used a weak phosphoric acid in distilled water. Rinse with water, then isopropyl alcohol. Then dry.

Will report back. Will also check cap. The label on mine is hidden.

Cheers, geoff

[Seiko Kid]

you have to remove them to test them. just desolder 1 side should do the trick

[dutchsiberia]

New battery on my 0634 seems to work. Light goes on and off as it should.

[767Geoff]

Thanks!

Mine is definitely buggy. Although the longer it sits the less buggy it is. I soaked it for overnight in a weak acid solution, then applied a stronger acid to solder points that I cannot get to, with an oiler. Rinsed, neutralized, dried and reassembled.


The left button will still only turn on the light in time mode, but not off. To turn the light off the set stem must be pulled then pushed. The right button correctly selects the digits to be changed in set mode. The left button in set mode only allows one increment at a time and then the set stem must be pushed in (at which time the light will then come on) then pulled, the correct digit selected and then the left button increments by one and the entire push pull select increment by one sequence repeated. In this manner I do get the time set correctly.

On occasion the set function works and corrects for more then one increment, then fails. This is of course way ahead of the dead watch with corrosion that I purchased.

Now I have found a place that will cut me glass ($15 a pop) so I can replace the chipped scratched lens. Has anybody re glued a new glass to the underneath backplate?

Cheers, Geoff

[Seiko Kid]

you mean re glued it onto the top of the brass mount that the old one is on ?


I have done that. The hardest part is getting the old one off in one piece
the seiko bonding is so strong. when you reseat the new one you need a black glass bonds as the paint comes away when detaching the old one and removing the old bond ( using black sharpie and regular clear bond won't work )

you need to sit in place roughly then assemble the watch so it is centred to the case - time consuming and not easy if your not familiar with the process

however you might be a real whizz at it without knowing !

[767Geoff]

Yep, top of bezel, oops! Not done that yet.

So a black glass bonds? Where and what brand. I have been looking for that product as the HP 01 also uses a black epoxy or bond glue..

Cheers, Geoff

[Seiko Kid]

been a while since i did it, Ill try and remember and get back

[Old Tom]

Seiko didn't actually use a black glue- the brass was blacked chemically, then printed and the crystal mounted using a clear epoxy. When you rip the crystal off you take off the epoxy and the top blacked layer (which is mechanically fragile). To fix this sort of problem I clean up the damaged area with a fibreglass brush then chemically black it using Birchwood Casey Brass Black- can take a couple of applications to get it really black. Dry it off on a radiator for a couple of days to harden the surface and then glue your new crystal in place using the tiniest fillet of epoxy around the edge. Clamp in place and leave to harden.

Black epoxy glues are used in jewellry making but the problem is the blackness is not that dense, alright for stone mounting where you may have 0.5mm of thickness but useless for crystal mounting where the thickness is probably about 0.05mm. Brand I have here is Hughes Associates Epoxy 220 Molecular Connector (black- comes in other colours). Does a good job of remounting Seiko C439 keyboards when the pesky thin keyboard surround disintegrates!

[767Geoff]

Tom!

Fantastic!

Will pick up the product. Yes, chemically treating metals to create blCk, like most black dials on Omega, Breitling etc up to the 60's were chemically oxidized silver.

Cheers, Geoff

[767Geoff]

Update,

Bizarre but the module has had a battery in for the last couple of weeks and was keeping perfect time, but with the always on light problem described above. I could turn the light out bu pulling and pushing the setting stem. This made setting extremely awkward.

Well, I put it away and the digital watch god fixed it. It is working perfectly now, so electricity seems to have resurrected a failed circuit.

Also purchased some blackening fluid and am having some spare crystals cut. Will epoxy a new crystal in to the polished and re blackened bezel.

Will also post before and after pics of the two 0624's that look pretty damn good now, and the third case with the blackened bezel.

The third module is untested as the LCD panel is cracked, and the positive battery terminal is broken. Will look into it later but I will have three cases restored to mint with two perfect working modules.

Cheers, Geoff