[Jukebox-list] Fw: Question

[david wendell]

Ron,

What a mystery!  I know the Twilight Zone now exists. 
I am not qualified to work on amps; I recap em and if
all is well I am happy.  When they don't work I take
em to the "amp guy".  He repairs them and tells me
what a dumb thing I did!

With my limited knowledge all I can think of is a
hidden jumper around the fuse or some foil up in the
fuse holder?  Maybe it was "super fuse" and wouldn't
open even if the National Christmas tree went through
it.  Sure sounds like a very bad 5U4 started it all. 
I do know it shows people like me to test with some
type of safety device in line before the amplifier or
anything else we are unsure of.

Sorry I could not be of any help but I did want to say
how much I enjoy reading your fixes for so many
jukeboxes.  We are very fortunate to have so many very
smart and willing people on this list!

David Wendell
--- Ron Rich <ronnnrich at yahoo.com> wrote:

> 
> Hi All, 
> I just had what I consider a very strange thing
> happen. I re-cap'ed a Seeburg MRA-5 amp and started
> to test it. I normally stick a light bulb in series,
> but this time I forgot. I did, however plug it into
> my amp meter, which is CB protected at 5 amps.
> I flipped the switch on and it was drawing the
> normal 1/2 amp, until the 5U4 tube heated up--then
> it "pegged" my meter, and poped the CB on the meter.
> I went into "duh" mode--looked at that thing for an
> error, tested the transformers, and could find
> NOTHING--I then re-tested all the tubes (including
> the 5U4, which was brand new). NOTHING--all good no
> shorts.
> So, I took it for a ride to my friends house. He
> looked at it--did probably the same tests that I had
> done, except for testing the tubes. ( I went inside
> the house and talked with his wife, so as not to
> "influence" his thinking) He said that there was no
> reason it should not work. So, he applied
> power--blew the 2 Amp CB installed in his test rig.
> It NEVER blew the 2a SB fuse in the amp--fuse is the
> "original" put in it at the factory.
> He said "it's gotta be a bad 5U4"--He installed a
> new one and we had music!  
> My question is--why didn't the amp fuse blow?  It's
> in the transformer primary for the 5U4 tube? I would
> have taken that bad tube home with me, to test it
> again for shorts, when warm in the tester-- except
> that it rolled off the table onto the floor--just
> broke the glass---
> Any ideas ??
> Ron Rich
> 
> 
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>      
>
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