K8064 Dimmer flickering with 650W

Kits General
1

Hi,
I assembled the K8064 dimmer and it seems to work. I use a 0-12v input and 230 V with a 650W theatre lamp.
However after a few minutes the low light settings start flickering.It seems to get worse the longer it stays on.
I have searched this forum and checked all suggestions (c12 = 100nF, TRIAC = TIC225M bourns, c13=0,47 uF). Only thing I haven’t tried is replacing the TRIAC. Are there any suggestions/solutions for where this flickering comes from?

thanks,
Hans (NL)

2

The trigger current for section IV is by far not sufficient (major design flaw). The TRIAC will only trigger in section I, conducting only DC. This will damage inductive loads. I do not see an easy solution for that, the µC is not able to supply the required trigger current even if R5 is reduced.