On 1/19/2013 6:04 PM, Jamie wrote:
Jeff Liebermann wrote:

On Fri, 18 Jan 2013 13:45:26 -0800, mike wrote:


If you find that it is a bad TD, you'll be tempted to sacrifice the
B-trigger to fix the A-trigger. Depending on the TD package,
there's significant risk of busting all the TD's. Mess with the TD's
as a last resort.


Yep. I found a bad tunnel diode in a 465B that I was fixing, so I
tried to move the B channel diode to the A side and ended up with two
dead diodes. Oops. I think I killed it with too much heat from my
soldering iron.

I eventually had to cannibalize them from another Tek 465 that had too
much damage to be worth repairing. I couldn't find any online at a
reasonable price. I was lucky and got two diodes out of the carcass.
Tucker has the diodes for $25/ea (ouch):
http://www.etestparts.com/Search.aspx?Mfg=TEK&Page=17

Info on tunnel diodes:
http://w140.com/tekwiki/wiki/Tunnel_diodes
http://w140.com/tek_xref_tunnel_diodes.pdf

I wonder if a NPN transistor used kind of backwards around a diode to
take advantage of the negative beta to give you that snap effect would
of done the same for you ?

Jamie

Remember that this was designed 40 years ago.
There are ways to get negative resistance, but the TD is/was simple and
fast.