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<div class="moz-cite-prefix">Hi Denshi,</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">The pin number of the 4520 is wrong,
the reset pins are 7 and 15. If you've wired it like in the
diagram then two outputs are connected.<br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">What you describe here is sometimes
caused by the capacitor not being able to discharge before the
next pulse arrives. <br>
</div>
<div class="moz-cite-prefix">Once the cap is charged up it can not
produce another pulse until it has discharged through the 68k/33k
combination. <br>
</div>
<div class="moz-cite-prefix">The base current can only go in one
direction leaving the cap charged if there was no other path to
GND. </div>
<div class="moz-cite-prefix">If the cap is big then it can take a
long time. <br>
</div>
<div class="moz-cite-prefix">I've had similar failures in these
pulse forming circuits when there is no discharge path. <br>
</div>
<div class="moz-cite-prefix">Sometimes I'm adding a diode between B
and E to provide a fast discharge path. Cathode would go to the
base of the transistor.<br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Best,</div>
<div class="moz-cite-prefix"> René<br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
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<div class="moz-cite-prefix">On 22.06.2024 00:01, denshi via
Synth-diy wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1965447145.4822909.1719007263163@mail.yahoo.com">
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<div class="yahoo-style-wrap"
style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;">im
trying to add a reset to a CD4520 but running into an issue:<br>
<br>
in the TKB serge uses a CD4520 to handle the vertical clock
(cycling between four vertical rows of pots)<br>
here is a relevant snippet of the schematic (as found on
hyperreal)<br>
<div>i copy and pasted the clock input to use as the “vertical
reset” and am sending that to an inverter to the bottom half
reset - it works, but only once, and then not again until i
power cycle. am i missing something simple here?</div>
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