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“found in several calculators but this specific one was from an SR7949D (only sold in the UK)”


The two GHU chips are made of a (high silicate?) epoxy I've never seen before.  
The silicate content makes chemically decapping them extremely difficult.  
Although I can get acid to penetrate a few mm to remove the epoxy it leaves 
a strong skeleton behind that so far I've only been able to remove mechanically.  
So this is where they stand:

GHU-03A: this chip has sustained enough damage now that I have to declare it "dead".  
We should get another one if its worth imaging.  I tried gradually more aggressive 
techniques to get the encapsulant off.  The last ditch effort was ultrasound which 
could work to knock the last layer off but is dangerous because on imperfect chips 
because it can cause a chip to crack...the latter happened.  I'm saving the remains 
just in case but if you *really* want this chip imaged we should get another one...
assuming I can figure out a way to decap it



package_top.jpg package_bottom.jpg decap3.jpg decap4.jpg




shard1_overview_mit2x.jpg shard1_sample_mit20x.jpg


mcmaster/commodore/ghu-03a.txt · Last modified: 2021/05/28 02:34 (external edit)
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