[sdiy] Help trouble shooting noisy circuit

[Mike Bryant]

You could flow solder onto the IC pins and then down the socket to prove if it's the problem.  Of course this makes the IC unremovable so best to use a new known good one.

________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Joe Frey <frey at radioles.com>
Sent: 12 January 2025 23:03
To: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: [sdiy] Help trouble shooting noisy circuit

Hello, more than a decade ago I built with Harry Bissell's help a pitch
to voltage circuit and an envelope follower and then built some
supporting boards: power supply and two invert-offset circuits. One of
the invert-offset boards is not functioning properly. It is a photo
etched circuit board unlike it's brother that was made on strip-board.
The invert and offset functions work properly but the output has a high
frequency wave in it whether there is an input voltage or not. The
brother circuit on strip-board works fine. Same power source for both. I
have checked the component values(there are only resistors), checked all
the traces with the circuit on paper, re-flowed all the solder joints
and replaced the TL072  with others. I still have the issue. What should
I look at next?

Is it possible that a faulty IC socket could produce this effect? I
didn't change the socket because this basement darkroom circuit board I
made then seems pretty fragile.

Thanks for any help. JoeF.


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________________________________
From: Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Joe Frey <frey at radioles.com>
Sent: 12 January 2025 23:03
To: synth-diy at synth-diy.org <synth-diy at synth-diy.org>
Subject: [sdiy] Help trouble shooting noisy circuit

Hello, more than a decade ago I built with Harry Bissell's help a pitch
to voltage circuit and an envelope follower and then built some
supporting boards: power supply and two invert-offset circuits. One of
the invert-offset boards is not functioning properly. It is a photo
etched circuit board unlike it's brother that was made on strip-board.
The invert and offset functions work properly but the output has a high
frequency wave in it whether there is an input voltage or not. The
brother circuit on strip-board works fine. Same power source for both. I
have checked the component values(there are only resistors), checked all
the traces with the circuit on paper, re-flowed all the solder joints
and replaced the TL072  with others. I still have the issue. What should
I look at next?

Is it possible that a faulty IC socket could produce this effect? I
didn't change the socket because this basement darkroom circuit board I
made then seems pretty fragile.

Thanks for any help. JoeF.


________________________________________________________
This is the Synth-diy mailing list
Submit email to: Synth-diy at synth-diy.org
View archive at: https://synth-diy.org/pipermail/synth-diy/
Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
Selling or trading? Use marketplace at synth-diy.org
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