Neutron optocoupler question

[skrunk]

I have one of those dual optos for a Neutron build but I'm a bit unsure as to how it connects to the board (RG Keen 1998-2006, Rev.1.01D).

The part is marked 805A OJ, with a white arrow as seen in the first pic below.
One end has 4 skinny legs and the other has two legs, one skinny and one fat, both the same length.
Going by the orientation of the white arrow in the diagram below, I've indicated the thin and fat legs.






So is the thin lead the anode (goes to square pad) and the fat one the cathode (goes to round pad), like this?

[R.G.]

Here's what I'd do.

1. Put a resistor in series with the LED side, either leg. Resistor value needs to be between 2K and 4.7K.
2. Get a 9V battery and a DMM.
3. Set your DMM to ohms and hook it to two of the skinny leads. It should measure high, 1M or more.
4. Connect the battery to the LED leg and the free end of the resistor. This puts a little current into the LED. One polarity of the battery will make the LED conduct, and cause the resistance reading to drop. Note the polarity the battery is - that tells you how to put them in the PCB.
5. This also tells you which of the four resistor leads are the two resistors. You'll need that too.

Make good sketches as you do this. This tells you the anode/arrow and cathode/bar side of the LED leads.

Then go to the PCB.

[skrunk]

cool, thanks RG.
guess I should have just thought about this logically.

[R.G.]

guess I should have just thought about this logically.

Before the internet and it's gigantic reserves of information for the sipping, I learned that necessity is NOT the mother of invention. Desperation - not THAT's the mother of invention! 

... now, lessee here, what can I do with a battery, some wire, and an (analog!) meter?

[skrunk]

ok I'm almost there with this thing I think.
I've got the pcb populated and everything hooked up (switches, pots, jacks etc.).

I don't think it's working right, but I'm not sure.
the effect seems to work as expected at all switch settings, but I'm not sure what I should be listening for when setting Rx.
I've got a 5k pot in place of Rx at the minute but I'm not sure what I should be listening for.
I get an effect at most points between about 560r and 5k, maybe I should just whack a 2.2k in there and be done with it.

I'm also getting whine.
I've hooked up the batt+ and batt- points to a dc jack and 9v power supply, with the ring of my input jack connected to R20.
the sleeves of both my in/out jacks are connected to the 'signal ground' pad at the top of the board.
the whine gets worse when I connect a battery.

also, when the direction switch is in the 'up' position, it barely passes signal when in bandpass mode and not at all in highpass mode.
in lowpasss mode theres signal but no filtering going on.
one of the lugs on the direction switch is unattached to anything, is this right?

some part substitutions I made:
10uf NP electro instead of 15uf NP electro.
4.7uf electro instead of 4.7uf tantulum.

everything else is stock.
chips I'm using: 3 x TL072CN and ICL7660SCPAZ

[R.G.]

the effect seems to work as expected at all switch settings, but I'm not sure what I should be listening for when setting Rx.
I've got a 5k pot in place of Rx at the minute but I'm not sure what I should be listening for.
I get an effect at most points between about 560r and 5k, maybe I should just whack a 2.2k in there and be done with it.

Rx is just there to diddle the amount of current going to the LED so that it doesn't either audibly bottom out or top out, and to get the range of the LED brightness to work with your setup (and YOUR LED/LDR). Each LED is slightly different brightness.

I'm also getting whine.
chips I'm using: 3 x TL072CN and ICL7660SCPAZ

I think it's the 7660. Those things are hard to de-whine unless you do everything perfectly. An LT1054 might help a lot.