LCD display and power issues

[Seiko Kid]

So, I have the following problem with my 0674. I dont feel this problem is solely linked to this particular model as Ive seen it with others in the past

If someone could explain what is causing the issue and how it can be fixed I would be most interested

[Kasper]

i would say that it's a problem with the polarisation filter..did you held one before (just on top of the watch) and tried again?

[Seiko Kid]

Watch the video again Kasper and note the seconds

[Kasper]

ok another shot then , i've seen it before 2..problem with the current..the visualization of the seconds can't follow. Everything works but the display gets not enough power to drive the segments. I'm not the electronics expert but i,ve read that the segments get darker as more current is added and that in combination with the polarization (view) angle. I remember that a had a watch were the digits got dimmer as the 8 apairs on screen.
So the problem must be between the displaydriver and the lcd.

[Seiko Kid]

Yeah, I had it down to a power issue but I would like to know the part it is so I can replace it. Also if I can take the part out of an 0634 circuit board as the 2 are very similar

[Kasper]

Thanks for the input. Based on your advice, I sanded the rubber strip with 800 grit. Under 10x loupe, they appear to be in good shape and are uniformly flat so I only applied very light pressure. I also cleaned the contacts with alcohol. The procedure improved another previously dim segment somewhat; but the original problem persists.

You could take a 1.5V battery and apply a voltage directly to the LCD segments (just follow their traces, they're a bit hard to see but not impossible). Once you found the 2 segments in question, see if you can control them individually or if perhaps the right-bottom segment always follows the state of the center segment.

Michel

[Seiko Kid]

Thank youn for your help kasper , the LCD is ok. I'm trying to trace the component that is at fault on the circuit board - all LCD prongs source back to the IC chip / I suspect my issue is prior to that

[elceedee]

My brother has one that all in a sudden started to skip the 6th minute to the 9th minute only between the 40th and 60th minute of the hour. Eventually I found him a working donor movement.
Ive read about a similar issue that a 0674 suffered in one of the listings on eBay (not mine, I sold one also with my brothers faulty movement). It appears that the cmos of the 0674 is vulnerable to these issues. Unfortunately this movement is build in practically one piece. I hope you can solve this great watch, but it might turn out you need a movement/circuit swap. Goodluck!

[Seiko Kid]

Usually this series of circuit is pretty robust. They all seem to suffer the same issues but this problem I havent come across before...

I feel it has something to do with a power unit located within the LCD. Ill perform a current draw test on it and see what the result is

[charger105]

I would say it's some sort of capacitive issue. They're not charging up quick enough, and/or not holding charge for long enough.
I'd investigate the capacitors (not the ones in the oscillator circuit).
Rgds.

[Seiko Kid]

Ok Charger

so here is an 0634 and 0674. I have transplanted the upper occislator board onto the 0674 from the 0634 and nothing has changed, still a fient display and slow changing digits
all my resistance readings are the same on both boards ( and also in another fully working 0674 circuit I have )

Could you explain to me please if there is anything I can test or how to retest the components ?

[Old_timer]

....still a fient display and slow changing digits...

I'm very interested in your work.
Are you absolutely 100% sure there's no battery/voltage supply issue to the circuit, and there are no issues with the circuit connections to the LCD screen?
What does it look like when you put a voltage source on one LCD element - does it appear darker than the circuit can achieve?

[Seiko Kid]

Im waiting on a capacitance meter to arrive for checking some components. I know the LCD itself is fine, I would like to build a power unit to enable me to test it. Hope to do that in the next week
I measured the current usage and its was almost nothing.....

[Seiko Kid]

So after some help from another member and also some purchases - Osscilascope and capacitance meter , along with a quick refresher lesson from my local electronics repair specialist I have found the problem

Now I am able to test the quartz and determine what voltage should be at each point . Also what are the important components, it was the IC chip that is failing . I suspect built into the chip are more capacitors ?

Anyway I have another problem now - after transplanting a known working Quartz I have a working module but after a few seconds it starts to run at twice the speed... I also tried a capacitor from a NOS board and it does the same?

I've played around with the trimmer but it has no effect

[Seiko Kid]

could it be possible there is no one on here that has an idea what the problem could be ?