Date   : Fri, 29 Oct 2010 17:53:13 +0100
From   : pete@... (Pete Turnbull)
Subject: Reversing the Tube ULA (destructively)

Ed Spittles wrote:
> On 28 October 2010 21:21, Pete Turnbull wrote:
>     Well, for your edification and delight, I tried an experiment a little
>     earlier this evening.

> I am both edified and delighted!  However...

:-)

> On 29 October 2010 01:02, Mark Haysman wrote:
>     I'll keep an eye out for a dead one to experiment on. If we were
>     going to
>     submit it to a lab for proper deconstruction, I don't mind supplying
>     a known
>     good one for that.
> 
> This could be the solution!  I'd be surprised if no-one on the list has 
> a broken second processor - but will anyone be prepared to donate the 
> presumed-useless Tube chip?  It still bothers me to destroy a working one.
> 
> But also, in your photo of the 3 generations:
> http://www.retroclinic.com/misc/tubechips.jpg
> isn't the top one plastic packaged?  Would that be depackageable with 
> acetone?

All the ones in the photo are plastic packages (and the last two are 
really the same chip).  Acetone won't affect those much.  As I 
understand it, in the common decapsulating process, acetone is just used 
to wash off the fuming nitric acid; you don't want to use water because 
nitric acid that's not pretty much anhydrous will etch away the metal.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York