Don't know why I'm not seeing the diagram (schematic). Here's what I know of chase circuits - the 555 has to be clocking (Pulsing from zero volts (ground) to positive (near the full voltage of the battery), unless regulated somehow). First thing I wondered was if the circuit is correct. The 4017 has an enable pin that must be held either high or low (not sure off hand). If it's not held properly then the chase lights won't chase. Those are my first two suspects, a non-pulsing 555 (non clocking) and an incorrectly wired enable pin.
Another possibility is the voltage supply. It may be higher than what the 555 can handle. I don't recall seeing a stated voltage for the power supply. IF you've over-voltage(d) the 555 it could be blown. (not clocking). And one last possibility I can think of - ESD (Electro Static Discharge (or Damage)). Remotely possible is an over-heating condition caused by too much dwell time with the solder iron on any given leg of any given component.
If you don't have access to very many test tools, you can build a simple LED Pulse detector. It simply connects to pin 3 of the 555, through an appropriately sized resistor, through a properly oriented LED. If the 555 is pulsing slow enough you can see it visually. If it is pulsing too fast to detect with the human eye (typically 27 pulses per second [PPS]) then moving it rapidly across your field of vision will reveal the pulses individually. Unless you're pulsing at such a high rate you can not see them even when you pass the LED through your field of vision. IF it is pulsing then you should see the same pulses at the clock pin of the 4017. If you have pulsing going on there then the problem is located in the 4017 chip. If you're NOT getting pulses at pin 3 of the 555 then the problem is there somewhere. You could be using the wrong value capacitor. Or your pot may be defective - or fully turned to one full end or the other.
I'd start there - determining whether the problem is with the 555 or the 4017. From there you can further diagnose the issue. If it's the 4017 it may either be a faulty circuit design, bad chip or an ESD related issue. In my 35 years I've seen plenty of failures due to ESD. Working at an ungrounded station while sitting in a cloth chair on a plastic floor protector and you're in your socks - BOOM goes the chip(s). My wife had a plastic floor protector at her computer station. Time and again when I'd sit there in socks (and other apparel), sliding my feet around I'd get a heck of a shock from ESD.
Like I said, it could be the chips themselves. They may have been exposed to an ESD event during shipping as well. Did they come in a metalized film bag? Were they stuck on black (conductive)foam? Were they stuck on PINK foam? (the pink foam is NOT static protective). Did they come loose?
I'll continue to follow this thread to see if I can at some point access your schematic diagram. Then I may even de-construct the PCB and reveal the traces to see if they follow the schematic. If I find an issue I'll speak up.
The datasheets for a 555 shows a minimum resistor of 1k where the pot on your kit is connected, but your pot can be turned to a zero ohms resistance at each end because it is missing a 1k resistor in series with each end.I am not sure what you are saying about turning the pot. How can you stop that?
Now that you mention it those are well worth a second look.Since the soldering is so poor then by shorting pin 6 to pin 7 of the 555 makes one circuit work, maybe because that pin 6 or pin 7 now is soldered but it was not soldered well before.
Leadless solder or plumber's solder don't work well. A cheap soldering iron that gets too hot incinerates the rosin in the solder.
Also I notice two solder shorts in the fuzzy photo:
Hmmm....seems like this board would have a better chance at working with a +6v supply, 74HC4017 chip, 1M pot, 1u Cap, and 430 ohm limiting resistor.The CB has not changed from mine, about 2004, until now but I see that mine has some different parts, pot 1M with 27k to + 6V supply, & several attached test leads to attach to bread board. Never had problems except replaced one bad red LED.
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by Jake Hertz
by Jake Hertz