Have you checked the continuity for that side of the circuit?
When I was trouble shooting mine I wrote down some of the voltages.
the problem will be on the left side.
Your voltages maybe different but should be close.
Where there are 2 voltages that would be on and off.
Well…the moral of this story is don’t let your 3 year old grandson near any electronic projects!! Hugo (for it was he) gleefully held the flashing Xmas tree in his hand and, without me realising, had proceeded to wiggle one of the capacitors so much that it had broken the track it was soldered to! All fixed now and flashing away merrily (and out of reach of the grandchildren!!) Thanks for all the advice.
Incidentally I am fascinated how this circuit, which on the face of it it two push-push circuits together, manages to change the flashing sequence without the use of an IC in the circuit - clever stuff…!!
I had the same exact problem as Alfonz. I discovered that the traces between LED 6 and 8, and the trace between LED 8 and 10 had gaps right near the solder points. After making a couple “bridges” the whole tree worked fine with all LED’s blinking. Personally, since three people have reported the exact same problem, my guess is those traces on the circuit board were either weak or broken already, and not an assembly problem.