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<p>Here's an oddity in my three metal can power supply. There is a
half inch screw wedged end to end between the two tallest metal
cans near the non-terminal ends of the cans. The screw is held in
place due to the spring force of the spreading cans against the
screw. It was placed there on purpose. I've seen that once or
twice on such metal cans in old tube radios.</p>
<p>What do you suppose the function of that screw could be? Resonant
vibration/buzz reduction?</p>
<p>JJS<br>
</p>
<div class="moz-cite-prefix">On 6/7/2020 9:25 AM, John Speth via
Synth-diy wrote:<br>
</div>
<blockquote type="cite"
cite="mid:51be25ec-322a-2cd3-93c0-d272f0762b3b@yahoo.com">
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<p>Hi experts,</p>
<p>I'd like to attempt hum elimination on a 1972 Wurlitzer 4027
organ. I'm pretty sure the bridge rectifier filter electrolytic
caps are aged to the point at which they don't filter so well
anymore. The power supply uses 4 inch tall multi-capacitor cans
mounted on the PS chassis with pins in the chassis and the cans
external to the chassis. All caps are employed for a total of 10
caps in three metal can packages. Are these antique parts even
available in new, recently manufactured form anymore? If so,
where?</p>
<p>There are three cans comprised of:</p>
<ol>
<li>500uF/25V x 2, 500uF/35V, and 1000uF/25V (4 caps)<br>
</li>
<li>1000uF/25V x 2 and 5000uF/25V (3 caps)<br>
</li>
<li>3500uF/25V and 1000 uF/25V x 2 (3 caps)<br>
</li>
</ol>
<p>Ideally, using exact replacement of new parts would be best
(and maybe costly, I fear). Non-ideally, I could wire new single
cap electrolytics but that would end up looking like a
frankenstein fix (probably work but bulky). Furthest from ideal
is buy a new current technology PS and use diodes or something
to drop the highest voltage to obtain the multitude of lower
voltages (22.5V --> 20.0V, 19.9V, 19.5V, 17V, and 10V). That
might solve the problem but any engineering miscalculation could
fry other parts of the organ.</p>
<p>Another question: There is a 0.01uF/1400V cap across the PS
transformer primary coil. What is the function of that cap?</p>
<p>Thanks, John Speth</p>
<p><br>
</p>
<br>
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