Re: Blown 150 Mhz Oscilloscope (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 24 Jul 2007 09:41:03 -0700
From: Ed Phillips <evp@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Blown 150 Mhz Oscilloscope (fwd)

Hello Dave,
   I would suggest a tube scope. They're heavy, but they're also nearly bombproof. They're much more forgiving than their digital counterparts. I imagine one of these could be picked up on ebay for relatively cheap. (much much less than 500 bucks).

for example: 
http://cgi.ebay.com/Vintage-Tektronix-Oscilloscope-Model-531-Vacuum-Tube_W0QQitemZ320139147519QQihZ011QQcategoryZ104247QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 
(or just search for ebay item # 
320139147519

Hope that helps.

Coiling In Pittsburgh
Ben McMillen"

	I've had exactly the same scope as my "regular scope" for a bit over 40 years and still use it even though I have a much newer Tektronix 545B and a Tektronix 465 "solid state scope".  The thing is darn heavy and I'd worry a little bit about being able to repair it if your're not "into electronics".  I do have to use contact cleaner on the controls and the plug-in connectors every few years and have replaced filter capacitors over the years but that's about it.  

	I have used the 531 to observe the output of TC's without problems but I'm always careful to keep it several feet from the coil itself - there's plenty of signal available to a small probe.  

	Solid-state circuits are very much more susceptible to transient breakdown than tube circuits although if used with care they are perfectly safe.  Don't know what you did, where the scope case was with regard to the coil, etc. but surprised you had that much damage - the most I would have expected was failure of the input channel in use.  Bottom line advice is that if you're new to this sort of thing start with a cheap tube scope with a few MHz bandwidth - main cost will probably be packing and shipping.  As for shelling out a kilobuck for one of those USB devices I'd skip it until I was a lot more familiar with use of and protection of a scope.  I'm afraid of them anyway for such applications because they're tied back into the PC itself which is equally vulnerable to damage.

	Any of these things used with proper care - if you fully understand what that is - should survive but why learn on something expensive when something cheap will do a perfectly good job?

Ed