SOLVED I need MORE (help with harbinger 2)

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Diynot

Well-known member
Moar speed, Moar depth! MBP Harnbinger 2. I get effect, but it’s weak sauce as compared to the Electrovibe. Depth has to be cranked and the max speed is barely half of the electrovibe. The vibrato setting is barely noticeable unless at max speed. I have checked components (several times in the rate section), I have reflowed ALL of the joints, checked for bridges, I have checked voltages, and found nothing exceptionally out of the range of expected, the trimmers have been tweaked and re-tweaked. I am using 9203 LDRs from Jameco. I tested and all 4 start at around 1.5k light and then 2/4 go to ab 6M dark, the other 2 close to 20M. The NSL-32 were procured from Smallbear. The hot potz reads at ab 93k. Mpsa13s (from Smallbear) were clocking in around 43k hfe. The only deviation from stock is using a 100uf cap instead of a 220uf on c26 which is in the power filtering and is followed by c30 which is a 220uf. Some pics:
IMG_4217.jpeg IMG_4216.jpeg
IMG_4215.jpeg
IMG_4191.jpeg IMG_4195.jpeg IMG_4214.jpeg
I did order a 200k Icar pot from smallbear in hopes that the extended resistance would grant me some extended speed range (but as I type this I realize greater resistance may equate to lower rates and that’s the wrong direction, meh). Sorry @Harry Klippton this was not the post you (or I) were hoping for.
 
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Calling out to @bean …. Yes, I should post this out on the home site, but hell, half the population here is the same as there and I am computer challenged and can’t get the pics uploaded. I did as you said and took my time….
 
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An update(?) to anyone listening…… I THINK the vactrols may be to blame for the lack of speed (or just the cumulative resistance of the lfo section as related to the vactrols). For the S&Gs of it, I bridged the legs of the LDRs and lo and behold we went ”plaid”….to the point of locking the lfo, but that is not a surprise. Moral of the story, I know the total resistance needs to come down at the lit side of the vactrol. Comparing the Electrovibe schematic I suspect I need to either lower R45/46 (purely speculation based on the fact that the Electrovibe moves the resistance of both 100k points in that section) or I need to change R41/43 (presumably lower since it is a series resistance). Anybody got a thought? I am probably misinterpreting the effects on cumulative resistance in this circuit and that’s why I need help. To add info, at dark resistance the nsl-32 I have is hitting around 5M. in circuit dark resistance is around 54k. Another thought, would adjusting the value of R52 down serve to make the vactrols internal LED brighter thus driving the lit resistance down (to a point)? @Chuck D. Bones @Big Monk ?
 
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Cooking with fire now, paralleling another 27k over R52 did indeed roughly double my rate. Measured the light resistance of my remaining nsl-32, 27k = 4.8k 13k = 2.7k 10k got me down to 1.9k, just don’t want to blow the LED so maybe going below 10k is questionable…. Though most CLRs in PPCB projects are 4.7k🤔 (Edit R52 is of course not a standard CLR having the MPSA13 attached so again not sure what lower R52 does to the stability of the circuit)
 
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I've built the Harbinger 1.5, which is essentially identical to the Harbinger 2.0. The only real difference is found in the power supply protection and in the speed control of the LFO section where opto-couplers are used instead of a dual-ganged pot. When I built mine I tried a few different LDRs around the bulb and found the 9203 to be weak sauce compared to the NSL-7532. The 9203s are not consistent across their batches, while the NSL-7532 LDRs are more spec consistent within their batches. (IMO, not all opto devices are accurate/precise elements. And there's a price to pay for inconsistencies.)

So with all that in mind, I'd first try out some genuine NSL-7532 LDRs around that primary bulb and see if your circuit perks up.
 
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Diynot said:
Gotcha. Having a hard time getting anyone to chime in here or at MBP so since it’s not locking the LFO probably just gonna do it. Worst that happens is I burn out the vactrol or the MPSA13.
Click to expand...
Just a quick observation of your PCB Build
Are Opto 1 or Opto 2 the correct orientation?
The BS250 Is supposed to be 180 degree to to the direction shown on the PCB??
Mr Bean confirms this will work the wrong way around but it will not be polarity protected.
 
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music6000 said:
Just a quick observation of your PCB Build
Are Opto 1 or Opto 2 the correct orientation?
The BS250 Is supposed to be 180 degree to to the direction shown on the PCB??
Mr Bean confirms this will work the wrong way around but it will not be polarity protected.
Click to expand...
From what I can make of your photos, both opto-couplers and the BS250 'appear' to be correctly oriented.

For the opto-couplers, the white-dot should be facing away from the camera lens and at the bottom (closest to the PCB) as shown in your pics.
And the BS250 'appears' to have the correct orientation as indicated in the build docs - because the silkscreen is backwards.
 
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I also see you have two different photos of the LDR positioning. One pic shows them flat against the PCB - not the way. And the other shows them standing up facing the bulb - this is the way.

Which way are they currently - flat against the PCB or standing up facing the bulb?
 
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music6000 said:
Just a quick observation of your PCB Build
Are Opto 1 or Opto 2 the correct orientation?
The BS250 Is supposed to be 180 degree to to the direction shown on the PCB??
Mr Bean confirms this will work the wrong way around but it will not be polarity protected.
Click to expand...
I have verified the orientation of the optos and since this is the revised board the bs250 is correct
 
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Cybercow said:
I also see you have two different photos of the LDR positioning. One pic shows them flat against the PCB - not the way. And the other shows them standing up facing the bulb - this is the way.

Which way are they currently - flat against the PCB or standing up facing the bulb?
Click to expand...
I started with them flat as is shown in the build doc, but after I opened up my Electrovibe and realized I had stood them up there I changed them. So they are currently standing up. Really though it has made no difference in the depth of the effect one way or the other.
 
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Diynot said:
I started with them flat as is shown in the build doc, but after I opened up my Electrovibe and realized I had stood them up there I changed them. So they are currently standing up. Really though it has made no difference in the depth of the effect one way or the other.
Click to expand...
Still, if they are the 9203 LDRs, they are suspect to my thinking and experience. Are they 9203s or are they the NSL7532s?
 
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music6000 said:
It seems strange that the stamp marking on the top is 180 degres between the 2 OPTO's & + on the board is marked for both bottom pads???
Click to expand...
Good catch!

DIYNOT - dbl-check the orientation of the opto-couplers. They should be oriented identically (the same way.) One appears to be backwards.
 
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music6000 said:
It seems strange that the stamp marking on the top is 180 degres between the 2 OPTO's & + on the board is marked for both bottom pads???
Click to expand...
I agree and sent up a red flag when I was verifying during troubleshooting, but I did verify the orientation before placing them, both by the dot and actually putting them into my little component tester to verify diode orientation and then by using my multimeter on diode setting, alternating the red and black probe placement to get a Vf reading vs null.
 
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