Breathing LED 555 circuit

[Kamel85]

Hi.

I have tried making this circuit but my led just keeps lighting.
I have re-built it several times, thinking i made some mistake connecting it, but same isue led is just on.
I tried with different 555, bc337 and 2n2222 but no luck, any ideas what i might have connected wrong?

Thanks /K

Update, I found the issue by replacing R4 100k ohm with a 1m pot, value needed for circuit to work was 1.3M ohm

[Kamel85]

I have another issue, i have now built the circuit on a perfboard but its very dim, maybe 25% as bright as the one on the breadboard with same led and powersupply.
exact same values of resistors, diodes, transistors etc are used
Any idea what component might be damaged?

[cheerio]

maybe the led is done. they tend to lose brightness when they die

[kam]

oh yes as cheerio said, make sure that the maximum voltage does not exceed the vfd of the led. As a matter of fact, better measure the max current through the led