Re: 465 does not trigger

Paul Amaranth

I see Tucker has a few at $25 ea.

On Mon, Feb 28, 2011 at 08:17:31AM -0500, bhaskins wrote:
Gala Dragos wrote:
Curve tracers are a luxury!
CTs can be quite inexpensive and you don't need any real accuracy as
long as you have a good scope and a assortment of precision resistors
Others on the list will disagree with this and I will admit that I would
buy a 7CT1N if I could find one at a attractive price.

I have probably put together over a dozen over the past 50+ years and I
still put together special setups if I need to explore some area of

I have a new set of diodes coming in, they are not impossible to find,
you just have to agree to the outrageous prices.
Where did you find them?
I have a 465B and I had to move the TDs over from the B TB.

*From:* unclebanjoman <mmazza@...>
*To:* TekScopes@...
*Sent:* Monday, February 28, 2011 3:58 AM
*Subject:* [TekScopes] Re: 465 does not trigger

One more thing:
instead using TD from a 475, you can use (temporarily) the TD in the
delay trigger section of your scope... just for a fast sanity check...
check your schematic.


--- In TekScopes@... <>,
Gala Dragos <gala_dragos@...> wrote:

Ordered a new set of 0125 diodes that will arrive in a few weeks. I
will defer the repairs until then.

From: Albert <aodiversen@...>
To: TekScopes@... <>
Sent: Friday, February 25, 2011 12:59 PM
Subject: [TekScopes] Re: 465 does not trigger

Hi Gala and others,
Maybe there is confusion about TD ratings in 465 and 475. The
trigger TDs in 465 are 4.7 mA types. Those in 475 are 10 mA types (at
least up to Sept '74). So if you try 475 TDs in a 465 the TDs
certainly will not switch. If you test 465 TDs in a 475 (your private
mail) then the TDs receive too much current and the result can not
confirm that that the Ip values are about 4.7 mA.

I have temporarily replaced CR652 and CR650 with another set of
tunnel diodes from a 475. The problems remain! Still rolling signal!


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Paul Amaranth, GCIH | Rochester MI, USA
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