Harbinger One bulb won't light on

[panicroom]

Hi all
This is my first time here.
I am having problem with Harbinger One build. As you can see from subject, the bulb won't turn on at all. There is 15v on both bulb pins and stable 15v on Q13 bulb side (collector) too. All other voltage readings are OK-all transitors. Tryed another Q13 with no cganges.
Rate led working as it should be, changing speed with speed pot (so LFO is working-I think).
I already check all solder joints!
Have no idea where to look next, so any advice is more than welcome.
Thanks in advance

[Spenzerleehorton]

Do you have another bulb to try?

Also try and dial down the voltage with the trimmers before you power up in case it's to high and blowing the bulb?

I've got Low frequency oscillating noise on mine without intensity up?!

[panicroom]

yes I've tried new bulb and test old one too. It is not a bulb! It is somewhere else!
thanks anyway

[HamSandwich]

You have 15V on the bulb, but it's lighting on at all? It's not always on right? You shouldn't have a steady 15V on any pin of Q13, which I think you know! Are you getting variable voltage on Q13's base or emitter? If the rate LED is working, there's something gone wrong between C26 and the passives around Q13. If you're getting variable voltage on Q13's base, then perhaps your Q13 is shot. Did you socket it or solder it to the board?

[panicroom]

Yes there is 15v on bulb and bulb is already checked - no light at all.
Yes stable 15v going thru bulb (when the bulb is in place) to Q13 (I know it should not be stable at Q13 collector).
Yes other two legs of Q13 showing variable voltages.
And yes I did socket Q13 and checked transistor already.
Thanks a lot

[HamSandwich]

When you say checked transistor - did you try another transistor in that place?

[midwayfair]

Post your voltages on all pins of Q11-Q13 and both pins of the bulb.

Check continuity across the pins of the bulb while it's in the circuit to verify that it's not shorted.

[panicroom]

Thanks for your replies.
I had second pcb, so I build a new one - perfectly working.
The old one is not connected any more (pots, switches, leds...) so I can not measure voltages at the moment. As I can remember, Q11-Q12 were ok. Only Q13 behavior was strange. Without lamp in the socket seem to be OK, but with the bulb it was like I describe earlier.
Yes, I have tried another transistor, and another bulb too.
It would be nice if I can repair it and finish it for my friend. Spent a lot of time debugging, but with behavior like this, don't know where to look any more.
BTW, could you recommend good photocells for my project (I am in Europe). Banzai Music sell "perfect for vintage Univibe (0.5Mohm dark resistance)", but everybody suggest hi-dark resistance. I did test some generic 0.5Mohm ldr with partial good success - at low speeds effect almost disappear. I know it is normal that effect is less prominent, but in this case is too much. Tried to fix it with adjusting trimm pots without significant success.
Thanks a lot