K8064 DC-Dimmer-Problem

I’ve got a problem width the DC-Dimmer
K8064. Adjusting the minimum level is
no problem but I can not adjust the
maximum level, what means I can not achieve
maximum power/brightnes.
The load is a simple/normal 60W 230V-bulb.
Symptom:
When I adjusting RV2 fully clockwise and
connect the analog input with 5V (2A power
supply) the green LED starts flashing. Then
I turn RV2 back step by step (counterclockwise).
The bulb becomes brigher but the green LED
keeps flashing and the bulb-light flickers
awfully (25Hz?)
Then I repeated the test with 10V at the analog
input. With 10V I can achieve, that the green LED
burns steadily, but then the bulb-light flickers
heavily.

Then, when I regulate the analog voltage,
bulb goes out, the green LED goes out an the red
LED flashes 3 times (what means, the dimmer stops
in error condition “Triac triggering
time out”).

I controlled all components on the PCB and the
soldered contacts. Everything seems to be OK.
What could be the mistake?

Greetings,
Reimar

PS: When I start the dimmer with 0V (after the
initialisation flashing), the green LED flashes 2
times what means, that the controller has detected
60Hz. But here in Germany the power line is served
with 50Hz. How is that possible?

Hi Grasbon,

Did you make sure that C13 is the correct value?
Should be 0.47uf /630

This is just a guess.

Yes.

C13 is correct: 0.47µF /630.

Reimar

Addendum: When the dimmer is adjusted to
full power, triac TR1 should switches continously
so that there’s no sound from L1. But in my case
the triac seems to pulse the bulb, so that L1 buzzes
loudly.

There could be something wrong with one of the Voltage sync (zero cross) components or the programmed controller (PIC16F676) is defective. R9/R10, T2, wrong value or defective C14,…