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Post subject: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Wed Apr 11, 2012 9:53 am
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Better close-up of mis-wiring of cap can of PR I worked on this weekend. I've seen quite a few mis-wired can versus cap under dog-houses. Anyhow, compare the leads coming off the SQUARE tap on cap versus the HALF-MOON tap--- between amp's wiring and the layout.

This amp was "serviced" about a year ago. So good tubes and over-built cap can kinda covered-up for a potential disaster. Old MIM Aero cap cans used to just "explode" their guts all over the chassis, when mis-wired.

Image

Image


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Post subject: Re: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Wed Apr 11, 2012 1:14 pm
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Wow! Yep, those two wires are swapped. Are those the only two wires that are wrong? I can't tell in that mess, looks terrible. :o

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Post subject: Re: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Wed Apr 11, 2012 10:37 pm
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Got tired of looking at the photo, but I'll take your guys word for it. Was that a pain getting the silicone off the eyelets? Sometimes I'll use a small amount between adjacent caps on the board, but only on the top side. Guess, Mr Dumble was the king of silicone use. Art

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Post subject: Re: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Thu Apr 12, 2012 12:55 am
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Art, the "King" of capacitor adhesive was on this old Princeton (non 'verb). Someone used Gorilla Glue (!?#!@$#&) to help secure the parts to the board! Yup, those caps were surely fixed to other caps, the board, the chassis. and anything else that happened to get in the way of the GG while it was drying.

Yes, the tubes were also Gorilla'ed to the socket. I guess to help reduce microphony. Or maybe tube-swapping. Or both.

After 5 pounds of Semtex (I hear one of it's main factories is next to the old Tesla plant--- this might explain some of this). The garage/workshop took on a whole new decorum. But, those caps still held tight to the chassis!

I'll spare you the photos... :lol:


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Post subject: Re: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Thu Apr 12, 2012 11:04 am
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gorilla glue!!!! man,I guess the guy never thought he would have to replace anything! :roll:


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Post subject: Re: Dreaded "PH" (Pre-mature Humming) & cap failure
Posted: Thu Apr 12, 2012 4:23 pm
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Gorilla Glue, never thought of that! Who needs no stinkin' solder!!!! Who needs no stinkin' tube retainers!!!! I like innovation, but...... Oh Well, Art

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