SOLVED Phase ll

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Daveyaj

New member
Ok so I am having some weird issues with a new Phase ll build.
First time I fired it up my LED was glowing nicely. Left trimmer (1k) would adjust brightness and right LED would adjust brightness as well? No pulsing from the LED.
After a few times going back to it the 1k trimmer came apart. The white dial popped off the top. 🤷‍♂️ So I unsoldered and pulled it and put a new one in.

Since then the left trimmer doesn’t do anything and the LED wasn’t really glowing at all. If I would squeeze the 1044 IC and socket between my thumb and fingers the LED would come on. So
after looking for possible solutions on the forum and inter webs I pulled the 1044 and prepared to swap in a 7660 which is the only other similar IC I have. But as I pulled the 1044 the LED came on. If I try to put something in that socket the LED goes very dim. With the IC in the 10k trimmers came brightens the LED.

I do get sound through it and I could hear some phasing in a dark room with a flashlight on the LDRs.

I can measure voltages and audio probe but I’m not really sure where to start and I’m hoping someone may have some guidance.

I measure all components prior to populating the board so I’m pretty confident it wasn’t just a wrong value resistor or capacitor.

Edit: I don’t have to pinch the 1044. If I place my finger over the soldered pins on the bottom of the board the LED comes on. I thought it might just be poor soldering but I reflowed those and same issue.

Any help would be sooo appreciated. I am building this for a friend and I have a nice UV enclosure ready to go!
 

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IMO and experience, the FLYLEAF sockets are extremely fragile.

704238a6-ebde-4e30-96a4-18ed8e94cd04-jpeg.25753


You may not have a fully broken pin/leaf, given that if you apply pressure with a finger it works, but ...

For peace of mind I'd definitely replace the fly-leaf with a machined-socket — even if that's not the primary problem here.


EDIT: Just saw your "EDIT" and that makes me think it's likely a grounding issue.

Hmmm
Odd duck, this layout — all ICs upright so pin 1 is upper left, all except the charge-pump IC. I see you've got the notch in the socket oriented correctly so assume you're inserting the 7660 etc in correctly. Usually Robert lays things out so ALL the ICs would be facing the same direction.


Maybe POST A PIC of the other side of your board, too...
 
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Thank you Feral Feline! Yes the orientation of that IC gave me pause in the build. I am putting the chip in correctly but I think I will plan on swapping that socket out with a machined one. I have tested all pins and they do show continuity but it could be different with the IC inserted.
The interesting thing is that the LED dims INSTANTLY when the pins touch the socket! Here are a few pics of the solder side.
 

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OK, so I tried to clean up my original board and couldn’t really get anything working any different. Figured I needed a restart. Populated a second board that I had. Worked through everything and both trimmers still just control the brightness of the bulb!
I don’t have a bunch of TL072 chips on hand, can I just swap out any standard op-amp to test each place?
Which part of this circuit makes the LED pulse?

I realize I don’t have the middle pot wired in. I didn’t want to have to remove it to troubleshoot. Again.
 

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NE5532, LM358, and JCR4558 are subs you could test the circuit with.

Check this thread for others:

DAJE

Thread 'TL072 substitute? (They're expensive now outside the USA)'

Worth a shot, I guess. TL072s are $2 each on Tayda right now. And I'm looking at a PCB that wants four five of them.

I could buy a bunch cheaply from other sources, but there seems to be some level of fakery going on with them. I don't feel confident I'd get in-spec results.

So: cheaper source of trustworthy TL072s for people who do not live in the USA?
OR
Decent substitute for less monies?
 
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Well in my limited experience the yellow LED one won’t work! 😂😂 Based on that alone I choose the green! I couldn’t get the KE-10720 from Tayda so I used 5516 from PPCB. This thing sounds so good and is really fun to play!
 
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