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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.</div>
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<div id="divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Joe Frey <frey@radioles.com><br>
<b>Sent:</b> 12 January 2025 23:03<br>
<b>To:</b> synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> [sdiy] Help trouble shooting noisy circuit</span>
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<div style="font-size: 11pt;">Hello, more than a decade ago I built with Harry Bissell's help a pitch<br>
to voltage circuit and an envelope follower and then built some<br>
supporting boards: power supply and two invert-offset circuits. One of<br>
the invert-offset boards is not functioning properly. It is a photo<br>
etched circuit board unlike it's brother that was made on strip-board.<br>
The invert and offset functions work properly but the output has a high<br>
frequency wave in it whether there is an input voltage or not. The<br>
brother circuit on strip-board works fine. Same power source for both. I<br>
have checked the component values(there are only resistors), checked all<br>
the traces with the circuit on paper, re-flowed all the solder joints<br>
and replaced the TL072 with others. I still have the issue. What should<br>
I look at next?<br>
<br>
Is it possible that a faulty IC socket could produce this effect? I<br>
didn't change the socket because this basement darkroom circuit board I<br>
made then seems pretty fragile.<br>
<br>
Thanks for any help. JoeF.<br>
<br>
<br>
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<div id="divRplyFwdMsg" dir="ltr"><span style="font-family: Calibri, sans-serif; font-size: 11pt; color: rgb(0, 0, 0);"><b>From:</b> Synth-diy <synth-diy-bounces@synth-diy.org> on behalf of Joe Frey <frey@radioles.com><br>
<b>Sent:</b> 12 January 2025 23:03<br>
<b>To:</b> synth-diy@synth-diy.org <synth-diy@synth-diy.org><br>
<b>Subject:</b> [sdiy] Help trouble shooting noisy circuit</span>
<div> </div>
</div>
<div style="font-size: 11pt;">Hello, more than a decade ago I built with Harry Bissell's help a pitch<br>
to voltage circuit and an envelope follower and then built some<br>
supporting boards: power supply and two invert-offset circuits. One of<br>
the invert-offset boards is not functioning properly. It is a photo<br>
etched circuit board unlike it's brother that was made on strip-board.<br>
The invert and offset functions work properly but the output has a high<br>
frequency wave in it whether there is an input voltage or not. The<br>
brother circuit on strip-board works fine. Same power source for both. I<br>
have checked the component values(there are only resistors), checked all<br>
the traces with the circuit on paper, re-flowed all the solder joints<br>
and replaced the TL072 with others. I still have the issue. What should<br>
I look at next?<br>
<br>
Is it possible that a faulty IC socket could produce this effect? I<br>
didn't change the socket because this basement darkroom circuit board I<br>
made then seems pretty fragile.<br>
<br>
Thanks for any help. JoeF.<br>
<br>
<br>
________________________________________________________<br>
This is the Synth-diy mailing list<br>
Submit email to: Synth-diy@synth-diy.org<br>
View archive at: <a href="https://synth-diy.org/pipermail/synth-diy/" id="OWA80522dc7-bc27-9e4d-79a0-dae60c29ed79" class="OWAAutoLink" data-auth="NotApplicable">
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Check your settings at: <a href="https://synth-diy.org/mailman/listinfo/synth-diy" id="OWAd6dd9373-4833-b74c-ef90-c81c245b282f" class="OWAAutoLink" data-auth="NotApplicable">
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Selling or trading? Use marketplace@synth-diy.org</div>
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