Got a Silvertone reel to reel that is buzzing LOUD. Even if the volume
is turned all the way down. 6EM7, 6EU7, 6AV6, 6X4. There are only two
big capacitors inside. A big ol' 40mf 300V yellow paper cap. And a 30mf
300V metal can cap. Neither one shows any juice when I meter them after
powering off. Just an edjamacated guess says that one of these two (or
both) is the culprit. What do you guys think?

in article , strat alot at
wrote on 3/19/05 6:48 PM:

Got a Silvertone reel to reel that is buzzing LOUD. Even if the volume
is turned all the way down. 6EM7, 6EU7, 6AV6, 6X4. There are only two
big capacitors inside. A big ol' 40mf 300V yellow paper cap. And a 30mf
300V metal can cap. Neither one shows any juice when I meter them after
powering off. Just an edjamacated guess says that one of these two (or
both) is the culprit. What do you guys think?

Yup. Replace 'em both.

Yup. Replace 'em both.

Also replace all of the other wax caps.

strat alot wrote:

Got a Silvertone reel to reel that is buzzing LOUD. Even if the volume
is turned all the way down. 6EM7, 6EU7, 6AV6, 6X4. There are only two
big capacitors inside. A big ol' 40mf 300V yellow paper cap. And a 30mf
300V metal can cap. Neither one shows any juice when I meter them after
powering off. Just an edjamacated guess says that one of these two (or
both) is the culprit. What do you guys think?

That is caused by crotch crickets, just during the time while the sun
crosses the equator on the way north. It will go away in six months.

Smiles a lot!! John Stewart

hey, thanks all. i set a bug bomb off in it last night to kill the
crickets 'cause i ain't waiting 6 months.

i think i'll see what happens when i change the two (coupling? izzat
what they are?) caps first. then go for the wax ones. there's alot of
those little buggers. and i'm good at getting burnt. (i should probably
change my tag to burnt-alot)

the silver can cap's polarity is marked on the pc board. but big yeller
isn't marked for polarity. there are two wires coming out of it : a red
one and a yellow. can i safely assume that red is positive? the red one
goes over to a juction that also connects to pin 6 on the EM87. The
yellow one goes to a pc board (ground?).

(strat alot) said:

the silver can cap's polarity is marked on the pc board. but big yeller
isn't marked for polarity. there are two wires coming out of it : a red
one and a yellow. can i safely assume that red is positive? the red one
goes over to a juction that also connects to pin 6 on the EM87. The
yellow one goes to a pc board (ground?).


Pin 6 of the EM87 is a system anode, so you're right about red being
positive.

--
Sander de Waal
" SOA of a KT88? Sufficient. "

Thanks Sander,
I think i'm wrong about them being coupling caps though. They must be
filter caps.

http://www.justradios.com/safetytips.html

On Sun, 20 Mar 2005 15:48:18 -0500, (strat alot)
wrote:

the silver can cap's polarity is marked on the pc board. but big yeller
isn't marked for polarity. there are two wires coming out of it : a red
one and a yellow. can i safely assume that red is positive? the red one
goes over to a juction that also connects to pin 6 on the EM87. The
yellow one goes to a pc board (ground?).

Dual electrolytic caps are possible. Are you sure, cross-your-
heart-and-hope-to-die, that there's not a ground connection from that
cap somewhere?

Grounding to a pc board sounds *way* too elegant. 'Course, I'm
"wrong alot".

Good fortune, and check the ground path,

Chris Hornbeck

Man I'm glad you said that.

I looked again and sure enough, there is a black ground wire too. Here
is the cap in question :
http://community-2.webtv.net/strat-alot/DoubleCap/

Now what do I do? Put in 2 separate caps? Will a couple of 47mf be good
enough?

(strat alot) said:

Man I'm glad you said that.

I looked again and sure enough, there is a black ground wire too. Here
is the cap in question :
http://community-2.webtv.net/strat-alot/DoubleCap/

Now what do I do? Put in 2 separate caps? Will a couple of 47mf be good
enough?


JJ has a double 47 uF/400(450?) V type in their range, should even fit
in the original space.

--
Sander de Waal
" SOA of a KT88? Sufficient. "