Harbinger One - led not working

[Manc]

Hi there. I've been scratching my head with this build for the past couple of days.
Here's what happens: when I power up the board, the LFO led glows and then goes off, and after this the bulb gets really bright. After a second or so the bulb starts pulsing as it should, while the led stays off.
It took me two leds to realise they were not bust (I took they just died, but no).

Also, and I think this is related, the speed is much too slow. Phased sound is coming out nicely, but compared to my other Harbinger the speed is about a half.
I have not subbed anything from the BOM, so i'm really puzzled here...

Thoughts?

[the3secondrule]

Help us to help you

We need voltages and photos of your build

[Manc]

Cheers

The regulator shows 17.20v at its input, 0 to ground and puts out 15.03v.
The LT1054 is as follows:

1: 2.83
2: 4.87
3: 0
4: 0.1
5: 0
6: 2.53
7: 1.44
8: 9.13

The led pads show 3.30v

And now the crappy pic

[Manc]

right. I think I spotted a mistake: I mistakenly soldered two 4k7 resistors in R52 and R53, instead of 47k's.
Will swap the two resistors and report back

[luks999]

hmm i dont think thats the problem though...

im looking at the wiring diagram in the build doc and it doesnt look right to me.
looks like when the effect is switched on, the L pad is pulled to ground, what of course causes the LED to go off.
in my opinion it must be the other way round, when the effect is switched off, then the L pad must to to ground, what causes the LED to go off

[luks999]

forget what i just wrote... i thought the "L" on the pcb refers to the "L" in the schematic
you wired it ok, but left the bypass LED out, whats ok

sounds like wrong parts, have you checked them again?
how does the resistor update improve the situation?

[Manc]

swapped R52 and R53 with the correct 47K as per BOM, no real change. Must have scr@wed up other values...
in the meantime I changed photocells in a working harbinger build: it used to have Banzai's matched LDRs, now I've put in the smallbears' specials
Boy are they huge. Need to spend some time with the trimmers, been fiddling a while this afternoon. Vibe's there but no cigar.

[luks999]

good luck man
i ordered tze smallbear specials. curious how they sound, let me know :-)

[Strassercaster]

 wow small world. i just installed the small bear hi low dark with covers. it made a noticible difference i highly recommend this over the nsl 7532s. i did something to mess up my pulsing led. it just stays on no pulse itwas working any ideas?

[Strassercaster]

my pulsing led was not pulsing it was running really hot 15 volts. i changed the q15 2n5087 transistor and it works. if you had the wrong parts you may have bombed that transistor.check c22 as well . good luck.the small bear ldrs hi low dark with the shield are better sounding than the nsl7532.i just put this up against a mojo vibe and a dunlup univibe the really good polished metal one with seperate foot controller. blind tone test with three different buddy guitarists. we all picked the harbinger one . last week the mojovibe and dunlop tied the harbingor came in first. these are the best three univibes i have messed with way better than the shaky jimi and the voodoo  labs microvibe and the chicken salad. i have never heard a neovibe but i imaginge the harbingor would tie or win in my book

[Manc]

Cheers fellas! Thanks for the support.
I swapped Q15 with a fresh '87 (note to self: next time socket the buggers!), still no pulse. I haven't touched C22 as it didn't look bust. No changes to the led and/or speed.

Sound's great but the speed is only half of my other Harbinger, even with the pot maxed out. I checked the 220K and 4K7 resistors which are in parallel with the pot and they read fine... I'm hitting a brick wall....

Edit: I've taken the LED off, and jumpered the pads... still to no avail...

[luks999]

hmm i would check the pot wiring...
the error has to be in the LFO section
good luck man

[Strassercaster]

definitely in the lfo section. Did you use a 2n5088 for q13. i did originally and switched to an mpsa13 gave me more speed. it is a lot more gain so you will have to re bias the bulb.

[Manc]

haven't got any MPSA13. I do have 18s though. Gotta check the datasheet to see if it's worth changing it... I thought this would just affect the brightness of the lamp?

[Strassercaster]

oh the mpsa 13 is worth changing. you will have to dim the bulb because it is brighter and faster with it. post your address ill mail you one😄