Scope on a rope Re: [sdiy] I have seen the light (litteraly)

[harrybissell]

Agreed !   I don't do the 'Fonze' unless it is on its way to the dustbin...

that said... I have repaired tube amps with a rubber mallet. Smack the
chassis and if it makes noise, you have a problem, Houston...   I hear that
Mesa-Boggie does something like this (these are TUBE amps I'm talking about).

A good scope probe is NOT optional equipment. It does not have to be super
expensive, but shouls be a 10X probe (1/10 of the signal... and 1/10 of the
circuit loading)

The next level of scopedom is to be able to trust what you are seeing.  I had
some
shit happen with my scope and I worked for two hours fixing the CIRCUIT when it
was the scope failing.  A quick (two hour) disassembly and reassembly fixed it.

H^) harry


anthony wrote:

> ----- Original Message -----
> From: "Scott Gravenhorst" <music.maker at gte.net>
>
> > "anthony" <aankrom at bluemarble.net> wrote:
> >>I'm glad this thread started, it made me get really sad that my scope was
> >>broken. But then it seems to have fixed itself. I did give it "The Fonze".
> >>That helps a lot. I also refer to that as "percussive maintenence".
> >
> > A word to the wise:  While I saw my father do this and "fix" an ailing TV,
> > it
> > is not considered a proper or good technique, should not be praised and is
> > highly discouraged.  If smacking the equipment "fixes" it, it is almost a
> > guarantee that the problem will return at a random time, probably a time
> > most
>
> Good points and I agree. And while I did these things and joke about them, I
> did not actually see it make an improvement. I said "that helps a lot" which
> was an off-hand remark, which I suppose I should have qualified by saying
> "It didn't do a dem thing".
>
> The nature in which my scope came back to life was gradual. When I first
> fired it up several days ago after leaving it sit for a long time one of the
> time-bases seemed to be malfunctioning. Over time as I played with it (after
> a few days of losing hope and almost giving up) it seemed to start working.
> I messed with it for hours last night and it just seemed to get better and
> better as I messed with it. This morning it's almost like it's even better.
> But I am still a little worried in spite of being glad that it works,
> because I do not know what was actually wrong with it. I did give it a very
> close visual inspection inside. I was not able to look at the pots and
> switches (which is where I assumed the problem was). Everything that I could
> see looked fine. I couldn't say I know exactly everything I should have
> looked for, but there were no loose wires, no cracked things, no patches of
> corrosion (which is what I was afraid I'd find).
>
> One theory I have is that a thin film of gunk settled down inside the pots
> and switches and messing with them a bunch wiped it away. When I first was
> trying to get it to work everytime I moved a switch or pot the display would
> show tons of noise. Now it does this very little.
>
> I don't really consider that to be a satifactory theory. I mean as far as
> wanting that to be the problem because I have no way of knowing if it really
> fixed itself or is just appearing that way for now. My experience has been
> that once switches and pots get noisy they usually stay that way. But maybe
> that's if it is only from wear.
>
> This is a scope that saw rigorous service at NWSC Crane and was retired from
> duty. For whatever that's worth. I figure it means it's still good for audio
> but not much else. That's my hopeful worst case scenario anyway.
>
> I stopped really using "The Fonze" technique when I had a guitar amp that
> acted up. Those things can shock your ass off through a guitar and no joke!
> I don't think I have (m)any lives left so I exercise caution at every
> adventure.
>
> I use it as a facetious term akin to "waving a dead chicken bone over it".