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Old 9th Feb 2019, 12:10 am   #23
David G4EBT
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Location: Cottingham, East Yorkshire, UK.
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Default Re: Capacitors for Trio 9R 59D

Quote:
Originally Posted by Humptydumpty View Post
The C40-41 -42 looked ok from under the chassis on no 1 but real bad bleed out on set 2 .
Yes, it was evident from the picture of the cap on your second set had leaked and was clearly in need of replacement. However, when you say the cap on your first set 'looked OK', you can't assume that just because it looks fine cosmetically, that it's fine electrically. You can only ascertain that by testing it to see if it's leaky (in the electrical sense) and thus passing excess current, and by checking the capacitance.

Often, on sets that are decades old it may indeed be the reservoir/smoothing capacitor causing excessive hum, but not always. For example, hum in Bush DAC90As is more likely to be caused by the output valve. The twin can capacitor in the '90A is very reliable - I won't be the only one to have needlessly changing one only to discover that the culprit was the output valve.

'Excessive' hum is a subjective term, but as you have two sets, you can at least compare them.
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