• Welcome to madbeanpedals::forum.

News:

Forum may be experiencing issues.

Main Menu

Harbinger One 2015 not working (LFO)

Started by Kardnez, March 14, 2025, 03:57:33 PM

Previous topic - Next topic

Kardnez

Hello,

I've finished building my Harbinger One (2015), but it doesn't work. The bulb glows continuously but quite dimly, and can only be adjusted with the Gain control. The Offset control has no effect on the bulb. The operating voltage is 18V. There's no signal coming from the circuit either, only in true bypass mode. I've checked the components without success and searched the board for solder bridges and cold solder joints. The Speed ��Pot is connected correctly. I've measured transistors Q11 and Q12, as well as capacitors C23, C24, and C25. When turned on, LED 1 flashes once.

The LFO isn't working, but as I said, there's no signal coming from the circuit either.

What could be the problem?

Thank you very much

Holger

Kardnez

Update:
I replaced Q11 and Q12 with 2N3904 transistors, and the LFO is now working. However, there is still no signal coming out of the circuit. The input signal is present at the base of Q1, but no signal is coming out of the collector/emitter. Q1 was also replaced with a 2N3904. The DC voltages in the preamplifier stage look good.
Does anyone have an idea?

Thx
Holger

NorthCoast

Can you post some pics?

What voltages are you getting on Q1?
"People discuss my art and pretend to understand as if it were necessary to understand..." - Claude Monet