Digital clock project error

[haygarth17]

I did built with my grandsons a digital clock bought from AliExpress. This is product I bought:

https://www.aliexpress.com/item/1005006658584103.html?spm=a2g0o.order_list.order_list_main.15.28a11802ENG6xd

The electric scheme and the display with error code is attached.
I can change hour and minute, date as well, all the settings actually the issue is the clock will always display this weird CSCS code and doesn't remember any settings I set. The seconds dot doesn't flash as it should and the only thing I can see when out of settings screen is this CSCS error.

Any help please.

[retiredfeline]

This is a wild guess. I think the CSCS message is coming from the firmware and maybe means Clock Stopped. Check if the lithium cell powering the DC1302 real time clock chip is flat.

[haygarth17]

Thanks for suggestion.
I did check the CR1220 battery. It has 3.2V, which should be OK.

[mikerj]

I'm pretty sure you have the third 7 segment display installed incorrectly, it needs to be upside down on these clock kits.  However check the build instructions very carefully, they may have changed the design so this isn't needed.

[haygarth17]

I did installed it the same with the seller picture (see attachment) and the way I did see it done in a YouTube video for same item.
Or maybe I don't understand what you mean by "third 7 segment display"

[haygarth17]

It might be something related with the clock, like Clock Stopped, because it is very weird the LEDs for seconds (the ones located in the middle of display) aren't blinking as they should. What should I check to see if clock does work?

[wasedadoc]

I'm pretty sure you have the third 7 segment display installed incorrectly, it needs to be upside down on these clock kits.  However check the build instructions very carefully, they may have changed the design so this isn't needed.

Not relevant. All four digits are in a single module.

[haygarth17]

All four digits are in a single module.

Yes, they are a single module.

[wasedadoc]

If you have a multimeter check the voltage at U2 pin 7. If close to either 0 or 5 that suggests the oscillator is not running.

[haygarth17]

If you have a multimeter check the voltage at U2 pin 7. If close to either 0 or 5 that suggests the oscillator is not running.

I did check it in two cases:

1. with external power ON: pin 8: 3.2V,  pin 7:0.24V, pin 6:3.37V, pin 5: 0V, pin1:5.09V, pin 2:0.31V, pin 3:0.43V, p4: 0V

2. without external power: pin 8: 3.2V,  pin 7: 0V, pin 6: 0V, pin 5: 0V, pin1: 0V, pin 2:0.14V, pin 3:0.29V, p4: 0V

[wasedadoc]

Those voltages seem ok.

[haygarth17]

Those voltages seem ok.

Below is the PIN description I found on Google for U2.

[ledtester]

Here's an idea: remove the DS1302 and see what the clock does.

[haygarth17]

Here's an idea: remove the DS1302 and see what the clock does.

Thanks. I did it and the CSCS message is still there.
The only difference I see is I'm unable to enter the settings anymore. (The way you enter the settings is to keep both S1 and S2 button pressed for at least 3seconds)

[m k]

Looks like a mirrored and flipped G instead of C.

https://www.eevblog.com/forum/beginners/completed-diy-kit-but-not-working/

[wasedadoc]

https://www.analog.com/media/en/technical-documentation/data-sheets/ds1302.pdf

Recommended crystal load capacitors are 6pF, not 22pF.

Can you get the correct time and date while using the settings buttons?

[mikerj]

All four digits are in a single module.

Yes, they are a single module.

Ok the design has changed, the earlier versions of this kit used discrete modules and one had to be installed upside down.

[Kim Christensen]

Check for solder bridges. Use a magnifier if your eyesight is dodgy.
For example, this soldering looks a bit marginal. There may be other joints like it:

[haygarth17]

Can you get the correct time and date while using the settings buttons?

Yes, I  can, but they are not saved. Once I move to time screen they are lost.

[haygarth17]

Check for solder bridges. Use a magnifier if your eyesight is dodgy.
For example, this soldering looks a bit marginal. There may be other joints like it:

I will check and refresh all soldering I have access to now. Many of them are covered by the display and that one I can not remove with the tools I have. More than this I'll try to change the oscillator and if all of this will not work maybe I'll buy another kit and do the work more careful.

Thanks all for your inputs.

[haygarth17]

I'll try to change the oscillator and if all of this will not work maybe I'll buy another kit and do the work more careful.

Just to let you guys know, I did change the oscillator and the error doesn't  go away nor changes.
As I mentioned I'll purchase another kit and hopefully that project will end well so my grandkids will be happy.

Thanks.