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Warhead - Lamp doesn't pulse

Started by glops, October 20, 2011, 07:46:43 AM

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glops

That's basically it. Two of the trimmers are controlling the intensity of the lamp brightness but when
playing the lamp doesn't pulse at all.  It's just stays on. Is there a common mistake that I could have made to cause this?

madbean

The lamp should pulse on its own. If it's lighting up then that's good--you are getting power. But, the LFO isn't working. You need to look over what transistors you've used and double check that you have also used the correct values in that area.

What kind of power are you supplying the board?

glops

Right now I have two batteries in series at 18 volts connected to the wires on the DC pads.  I checked all
the resistor values on the board and everything was correct.  For the transistors I subbed Q14, Q13 with BC109b's and all 5089's for the 88's.  Is the LFO section on the schematic the bottom part with all the stuff surrounding the BC549's?

glops

I didn't have the LED soldered in. ONce I did that everything started working


madbean

Ah, yes that makes total sense! The LED pulses with the LFO and without that path to ground, no LFO. I wish I had thought of that when this first came up!