Nixi Clock Board Identification - It will not keep time

Thread Starter

mlfrancis

Joined Dec 18, 2017
4
Hello All,
I love old clocks, electronics, and ham radio, so my wife bought me this Nixi clock for Christmas. It has developed a problem with either running slow, or stopping for several seconds before continuing with now lost time. Anywho, my assumption is it was a kit built and sold by the person she bought it from, but I could be wrong about that. I wanted to find a schematic online but haven't had any luck. As a hail Mary, decided to throw a picture up here to see if anyone recognizes it? My assumption is there is either a problem with the crystal, clock chip, or maybe the PIC chip since it runs off a 12v wall-wart. If anyone recognizes it or has a tip for fixing, it then much thanks in advance.
 

Attachments

Ian0

Joined Aug 7, 2020
5,147
The critical point is around pins 1and 2 of the DS1307 (the point that the crystal connects to). The soldering around there looks messy and there seems to be a surface mount component on pin 2.
Also, I don’t see any decoupling capacitors throughout the entire project.
 

Thread Starter

mlfrancis

Joined Dec 18, 2017
4
The critical point is around pins 1and 2 of the DS1307 (the point that the crystal connects to). The soldering around there looks messy and there seems to be a surface mount component on pin 2.
Also, I don’t see any decoupling capacitors throughout the entire project.
You're right about the nasty soldering and SMD there. I hadn't even noticed the SMD. I need to get a better view, but zoomed in with the camera and I don't see any kind of markings so maybe an SMD cap of some sort.
 

Thread Starter

mlfrancis

Joined Dec 18, 2017
4
Welcome to AAC!
Contacting the seller isn't an option?
Well, replies have been sparse. My wife bought it from Russia. It was quite interesting getting it because Russian customs sent it back to him I think twice and then it eventually got here almost two months later. I've thought about just gutting it and rebuilding it with a pi, but the curious side of me wants to know what's wrong with it.
 

dl324

Joined Mar 30, 2015
14,467
I've thought about just gutting it and rebuilding it with a pi, but the curious side of me wants to know what's wrong with it.
The soldering is pretty bad. Look for bad joints.

If you want help from someone else, you're going to have to trace the circuit and make a schematic.
 

Ian0

Joined Aug 7, 2020
5,147
You're right about the nasty soldering and SMD there. I hadn't even noticed the SMD. I need to get a better view, but zoomed in with the camera and I don't see any kind of markings so maybe an SMD cap of some sort.
There shouldn't be any caps around pins 1 and 2, because the Dallas devices have their own built-in crystal loading caps.
If there is extra capacitance there, it will affect the crystal oscillator and it might not keep time, or it might not run.
 

BobaMosfet

Joined Jul 1, 2009
1,979
Hello All,
I love old clocks, electronics, and ham radio, so my wife bought me this Nixi clock for Christmas. It has developed a problem with either running slow, or stopping for several seconds before continuing with now lost time. Anywho, my assumption is it was a kit built and sold by the person she bought it from, but I could be wrong about that. I wanted to find a schematic online but haven't had any luck. As a hail Mary, decided to throw a picture up here to see if anyone recognizes it? My assumption is there is either a problem with the crystal, clock chip, or maybe the PIC chip since it runs off a 12v wall-wart. If anyone recognizes it or has a tip for fixing, it then much thanks in advance.
Can you show us the NIXIE side, please? Just curious what it's driving ;)
 
Top