SOLVED I need MORE (help with harbinger 2)

[Diynot]

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:



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.

 

[Diynot]

Still, if they are the 9203 LDRs, they are suspect to my thinking and experience. Are they 9203s or are they the NSL7532s?

They are 9203s from Jameco. I used them in my Glasshole build w/o issue. I did measure them prior to placement. all have a light resistance of ab 1.5k, 2 have dark resistance of around 20M the other 2 around 5M

 

[Diynot]

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.

Is true I went in knowing the 9203 is a less optimal LDR, but considering the 7532 seem to be unobtainium and since the Electrovibe uses the 9203 with no ill effect I rolled the dice. I would def say the 9203s could be resulting in the lack of depth and vibe, but I will have to order new ones to even test the theory. Cooder said he used the gl5549 so I may try those

 

[Cybercow]

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.

DIYNOT - dbl-check the orientation of the opto-couplers. They should be oriented identically (the same way.) One appears to be backwards.

 

[Diynot]

DIYNOT - dbl-check the orientation of the opto-couplers. They should be oriented identically (the same way.) One appears to be backwards.

I have, they are correct. Even though the case imprint LOOK wonky, they have been tested and the dot aligned

 

[Cybercow]

I have, they are correct. Even though the case imprint LOOK wonky, they have been tested and the dot aligned

That being the case, my best guess at this point would be to start signal tracing things to try and discover what's going wrong.

 

[Diynot]

My plan from here is to take the advice of @jimilee from over on my MBP thread and throw a trimmit on R52 to resolve the speed issue and look for some more legit LDRs to see if that helps the depth issue.

 

[Diynot]

Gonna mark this as solved since subbing a 10k for the 27k has gotten me more speed and even the depth seems to be acceptable. Could I maybe tweak the speed a little more, maybe, do I have some GL5549 LDRs on their way to maybe get just that much more out of it, yes, but overall I am satisfied with what I’ve got. Thanks for all the input.