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Harbinger One - Lamp oscillates several cycles then is steady

Started by Sburrell63, March 10, 2017, 06:35:20 AM

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Sburrell63

Troubleshooting Harbinger One -  2015, 9v power variant (D1 removed). lamp executes several cycles then slowly dims to a steady neutral glow (~9v). I've completely rebuilt the whole sub-circuit for the lamp and re-tested voltages, resistors, capacitors, transistors, and SPD1/2 for proper values. Gain/Depth seem to work as does SPD.  If I manually ground Q11 base, lamp cycling starts over only to settle to steady glow.  So it would seem to be upstream issue with C23-C25.  Voltages hold steady from power circuit so am getting enough voltage. Any ideas?

midwayfair

Does it take longer to die depending on where the speed is set -- that is, do the same number of cycles pass before it stops oscillating?

Sburrell63

The number of cycles varies by the INT (intensity) pot.  lower intensity yields 10-11 cycles regardless of SPD1/2.  Higher intensity yields 1 cycle at highest setting. 

Sburrell63

The SPD1 connection to the PCB was faulty.  The PCB was actually damaged, probably during the build.  I patched from the SPD1 link to downstream resistor and violla~.   Solved.  Vibing like a rock star now.