IanB

Right. Swapped over the pot PCB’s. It’s not that. Have I screwed up the gyro circuits x 2?


jsteiger

Right. Swapped over the pot PCB’s. It’s not that. Have I screwed up the gyro circuits x 2?
I am thinking you have 4 gyrator sections messed up.

GR4 should be 1k87 and you have it 187k.

GR19 should be 2k05 and you have it 205k.

Find where you put the 1k87 and 2k05 and swap those parts and I'm betting your weird shelving action with the upper bands will be correct.
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IanB

And of course you are right!!
Working on all freq’s!
Thank you so much for your time & help!
So stoked!

I finished my pair of LC40s. Upon applying power, both units smoked. (I did test them one at a time) When I looked at the circuit, PR4 and PR5 are the items that look cooked on each unit. Did I follow the directions wrong in the exact spot on two different units a couple days apart?! I s’pose that’s possible. These are the 10 ohm power damping resistors. Any ideas?

jsteiger

I finished my pair of LC40s. Upon applying power, both units smoked. (I did test them one at a time) When I looked at the circuit, PR4 and PR5 are the items that look cooked on each unit. Did I follow the directions wrong in the exact spot on two different units a couple days apart?! I s’pose that’s possible. These are the 10 ohm power damping resistors. Any ideas?
https://groupdiy.com/index.php?topic=63983.msg814157#msg814157
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So I did some inspecting, trying to figure out the issue. Replacing the resistors and using a different opamp got the eqs working perfectly and they sound great. So the issue seems to be with the opamps. I was able to visually inspect the solder joints, but that's about the limit of my knowledge. Any hint for my steps?

Inspecting the board doesn’t show any funny solder connections. The two units failed in the exact same way, but I don’t know what to look for beyond solder issues. Anybody got a tip?