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Old April 14th 07, 11:13 PM posted to rec.radio.amateur.boatanchors
Chuck Harris Chuck Harris is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 270
Default Replacement electrolytics

Dave wrote:
I have just re-capped the power supply capacitors in a DX-40 with 40uf
450 VDC Aluminum Electrolytics from NTE Electronics in New Jersey.

I have noticeable hum on the carrier. Measuring the ripple voltage with
a 10 Megohm ac coupled meter shows 2.3+ volts [average/rms ...
non-sinusoidal] on the 600 vdc line and 1.2 volts [average/rms ...
non-sinusoidal] on the 300 vdc line.

It appears the RS of the capacitors is way too high.


Your ripple values look ok to me. They calculate out to
be under 1%. (0.4% rms)

You probably have a problem elsewhere, such as a heater-cathode
leak, or short.

-Chuck