Seiko LC O624 fault question, please.

[70's_gal]

Hi guys, hope you can help a gal out. Last week I picked up a Seiko O624-5009. All looked well when the watch was cold, but as it warms up (i.e. on the wrist), the hour, minute, and seconds digits begin to break up. Not the same segment of each digit set, either. And different segments will shut off at different times. Let the watch cool down, and all returns to normal. Timekeeping itself is just fine.
Pushing/pulling/gentle twiddling with the setting button at 3 o'clock helps light all the correct segments, but it doesn't really last.

Can anyone point to a specific component or area of the module where the broken circuit might be? The LCD panel itself, maybe? I haven't worked on a vintage Seiko LC in awhile, and never on an O-series. Thanks in advance!

~Sherry.

[Old Tom]

First of all go and download the technical manual from digitalwatchlibrary or one of the Seiko sites. The 0624 is very simple inside and any repairable faults are usually done by cleaning/careful reassembly. The fault you describe sounds like a poor earth connection to the LCD panel. Inside the 0624 you have the LCD panel sitting directly over the main DIL MOS chip lying on its back with its legs in the air (stop making your own jokes!). The pins on the chip make direct contact with the panel and must be very carefully adjusted to all be at the same height (detailed in tech manual and something of a black art). Be aware if you remove the chip and rear frame from the plastic LCD carrier getting the two back together without damaging the chip pins is..... fun! I use two strips of 100g white paper cut to the cutout size and place these between the pins and carrier to act as guides and to prevent the pins getting bent (need photo!), when the two parts are back together you pull the two bits of paper out and all done with no bad language!

It doesn't sound like a button spring contact problem but always worth inspecting/cleaning/lubricating these (microscopic drop of red DeoxIT on Seiko GP contacts works wonders).

[70's_gal]

Thank you so much! Great information! I will download the schematics and give your suggestions a try.
Cheers!
Sherry.

[70's_gal]

Finally made the time to clear off my repair bench and tackle the fault on my O624. It turned out to be easier than usual. This metal frame holding down the LCD panel had shifted slightly, allowing the panel to separate slightly when the watch warmed up:

I gently reseated the LCD panel to make sure all the segments were working, add a touch more curve to the metal frame and reseated it properly, and tested it with gentle heat. Success...the module now works perfectly warm or cold. No more disappearing segments.

My P624-5009 disassembled:



And working again!


Love the way these earlier Seikos were put together.

Cheers,
Sherry.

[retrowrist]

Hello,

Did this require any soldiering? How did you disassemble you 0624 LCD panel. I have a totally different problem with my 0662, but would like to get at the setting lever switch on mine, and can't find out how. But anyway, you fixed your problem, and that is what counts. Good for you.

- Patrick

[70's_gal]

Hello,

Did this require any soldiering? How did you disassemble you 0624 LCD panel. I have a totally different problem with my 0662, but would like to get at the setting lever switch on mine, and can't find out how. But anyway, you fixed your problem, and that is what counts. Good for you.

- Patrick

No, no soldering. The LCD panel is held in place against the "zebra" strips by that curved metal frame. I assume the LCD paned had shifted/lifted just enough to cause it to break contact when the watch warmed up. The repair was just a matter of reseating the panel and making sure the metal clip kept the panel secure. Getting at the setting lever will mean you will have to go deeper into the module, I would think. Good luck.

~Sherry.

[retrowrist]

I see, Thank you sherry for your input.

FUN FACT: Did you know Sherry that the Seiko 0662-5009 and the 0624 "modules" are almost exactly alike! I want to say that they are exactly alike, but I am not totally sure. Old Tom would know. He is keen to these models. And the predecessor to the Seiko 0624 was a watch that looked like an astronauts wrist watch, and was no where near as lovely as the 0624. I remember reading something that Old Tom posted way back when about the rarity of finding even "1" perfect "0614." There was always something that developed wrong with them over a few years: Bad circuit board, bad LCD panel, Cracked LCD ect.

Anyway, thanks a lot.

- Patrick

[bucko170]

Love the front buttons and the colour of the LCD background, super cool

[Phasar66]

Very nice watch and good photos. I have an old
Timex and the module in built very similar, is not working.
I will try my luck to see if I can revive it. I'm craving for a watch like yours.

[70's_gal]

Love the front buttons and the colour of the LCD background, super cool

Actually, that yellow-ish filter (a kind of gel filter) is in front of the LCD panel! No idea why they did it that way, nor even why they did it at all. The LCD panel has more contrast and legibility without it, but it does look very cool.


~Sherry.

[rewolf]

Actually, that yellow-ish filter (a kind of gel filter) is in front of the LCD panel! No idea why they did it that way, nor even why they did it at all. The LCD panel has more contrast and legibility without it, but it does look very cool.

Early LCDs often had this yellow filter, also in pocket calculators.
The filter was supposed to keep UV light away from the LCD, to avoid degradation of the display by UV light.

[vpn]

Nice watch Sherry! I agree that the yellow-ish filter makes it look cool! It's great to see that works again. Once I had an old LCD watch with a similar filter on it (but I don't remember if it was a Seiko, it wasn't a calculator watch though, the calculators came after that one). It got scrapped many years ago because it stopped working suddenly... Somehow I regret what I did back in those years!