Harbinger Lamp not lighting (Solved)

[pryde]

Damn. I built the circuit and it was working fine before boxing it up. Now after getting it all done the bulb is not working? The effect turns on and I can hear the controls effecting the sound but there is no modulation d/t the bulb.

I have looked very closely and it does not seam the bulb filiments are broken. Also, I did jumper the LED pads as I was not having luck with getting a pulsing LED.

Where to start? I guess the bulb could have broken during boxing but I was very careful and it does not appear to be broken? Are these really delicate?

I am getting ~13.5v off of Q11/Q12 collector as well. What else should I check?

*** UPDATE- while probing around I accidently jumped the collector and base of Q13 together and the buld lit up very bright  

So this at least tells me the bulb is not broken. I swapped in another 2n5088 in Q13 but still no luck... suggestions

[madbean]

Your voltage is low for some reason. What are your voltage reading going into the regulator? Is it 18v (approximately)?

[pryde]

OK, found the original issue after HOURS of troubleshooting  When tightening the vol pot to the enclosure, it somehow was grounding and cutting of the LFO/lamp ?. Placed a nut on the bottom side and all is good there and the lamp/effect is working....

As far as voltages something still is not right. I am only getting 9.8v into the regulator and now Q11,12 are getting ~9v to the collector. I tried swapping the charge pump but the results are the same. Any ideas?

BTW: I am using a 1 spot through the filter pcb.

[madbean]

Something is wrong with the charge pump area then. You should be getting about 9v on pin8 of the charge pump and about 18v into the regulator and 15 out. That's where you need to focus.

You did wire the filter PCB to the 9v/G pads, not the 18v pads, correct?

[pryde]

Something is wrong with the charge pump area then. You should be getting about 9v on pin8 of the charge pump and about 18v into the regulator and 15 out. That's where you need to focus.

You did wire the filter PCB to the 9v/G pads, not the 18v pads, correct?

Yes, filter pcb is wired to 9v pads. BTW: I am using 220uf's on the filter pcbs.

Here is what might be the issue but not sure. R54 (100R) is on the filter pcb and is knocking my incoming 9v down to ~5v. Should the resistor be omitted if using 9v instead of 18v? If so, do I just jumper the pads?

[madbean]

Are you sure it is 100r? Go ahead and remove it and install a jumper in its place.

[pryde]

Good to Go 

It was R54 (100R) on the filter pcb. It was choking the 9v right from the start. Removed it and jumped the pads and have 15v coming out of the regulator. Everything sounds absolutely great.

Maybe reflect in the build doc to be sure and omit R54 and jump if using 9v into the filter pcb? This was likely why I was not getting LED pulse as well. Already boxed and not going to worry about that now.

[madbean]

Yeah, that is very strange. Normal voltage drop would be pretty small. Could be the current draw of the circuit is proving to be too much for a 1/4W resistor? Not sure. I'll look into this and see if I can re-produce the result you have.

Alternatively, I can suggest using a 1n5817 there. If it is something I've bonked up, then my sincere apologies. There is maybe a larger issue in play about this kind of filtering that I'm not realizing.

[pryde]

Its all good, gotta work the kinks out sometimes. This thing sounds incredible. Thanks for the great project.

FWIW: I made a reflective shield for the lamp array but since the photocells are pointed directly at the lamp it probably doesn't make much difference.