Harbinger One - Rate LED not flashing

[Rockhorst]

Two questions:

1) what's the benefit of the buffered rate LED circuit in the 2015 Harbinger compared to the old version? Is it to prevent ticking?

2) I subbed a BC560C for the 2N5087 in the rate LED circuit and the LED doesn't flash now. It does sometimes, but usually is just permanently on. Maybe I see a very faint flickering. Could this be due to the substitution? I looks to me like the 1uF cap may be charging up to quickly and the potential not going down anymore. Maybe subbing a smaller cap will fix it, but maybe there's other ideas?

Other than this, the build is working fine by the way

[Rockhorst]

Don't know what was wrong, but I replaced the 1uF electrolytic with a similar one and now it works fine.

[cooder]

I read somewhere on here on some old thread that someone replaced the 1 uF with a 10uF and that solved it, from memory...

[Axeman]

I read somewhere on here on some old thread that someone replaced the 1 uF with a 10uF and that solved it, from memory...

Which 1Uf  did you replace?

[Axeman]

I read somewhere on here on some old thread that someone replaced the 1 uF with a 10uF and that solved it, from memory...

Which 1Uf  did you replace?

[somnif]

I read somewhere on here on some old thread that someone replaced the 1 uF with a 10uF and that solved it, from memory...

Which 1Uf  did you replace?

I assume he's talking about C22, the cap in the Rate LED portion of the circuit. Its the one controlling the tickle on the base of the transistor lighting the LED. Bigger cap would mean more juice needed to trigger a flash.

[Axeman]

Ok I'll change C22 and R55 with no positive results.  My light does not pulsate.

[madbean]

I used this circuit to replace the original mainly because putting an LED in line with R45 does work for flashing but it also does have some effect on the LFO overall. I wanted to have something that operated without influencing the depth of the LFO in any way.

Not sure why one 1uF would work over another. Looking at it again, I think I could have done something better with that flasher circuit.

[Axeman]

Like Q13 and Q15?

[madbean]

Like Q13 and Q15?

Try a 10uF for C22 as suggested. But, you can test it first! Simply touch the leads of a 10uF cap to the soldered leads of the 1uF in C22 and see if the LED starts pulsing. This is just to see if greater capacitance on C22 has an effect on the end result.

I can look at the circuit again but probably not for a couple of days. I seem to remember having trouble getting it to work with an NPN which is why I used a 5087. But, it's been a few years

[Axeman]

Well if I get it work I'l buy 2 more and 2 of the Harbinger 2.  I build Plexi amps and 800, so I have a general knowledge of this stuff. 

Thanks

[Axeman]

Well, I replaced Q15 with a new 2n5087 I tested it as well and now the red led doesn't turn on.  I also used a 10uf to jump/bridge c22 and the red led will flash once and dim off.  I'm starting to wonder of the thin copper circuit is to thin and dissolves after heat of a soldering pin is applied.

[Axeman]

Ok, really embarrassing question is the 100KC dual log pot or dual Anti-Log?

[cooder]

It's a  dual Anti-Log.
Also called 'reverse audio' http://smallbear-electronics.mybigcommerce.com/alpha-dual-gang-16mm-solder-terminals-100k-rev-audio/

[Axeman]

Got it, I have the right one installed and still will not work.