Cory Posted June 14, 2022 Share Posted June 14, 2022 Does anyone know the purpose of this mod? It appears to be tied to the keyboard, but not clear what the diode is protecting. Also, should I be posting these types of topics in this thread or the development thread? 1 Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted June 14, 2022 Share Posted June 14, 2022 1 hour ago, Cory said: Also, should I be posting these types of topics in this thread or the development thread? This would not be a development topic. Quote Link to comment Share on other sites More sharing options...
+jedimatt42 Posted June 14, 2022 Share Posted June 14, 2022 Looks like the motherboard equivalent of the diode fix for the capslock/joystick up fix.. Quote Link to comment Share on other sites More sharing options...
Cory Posted June 14, 2022 Author Share Posted June 14, 2022 14 minutes ago, OLD CS1 said: This would not be a development topic. Thank you. I'll post future topics like this over there. 1 Quote Link to comment Share on other sites More sharing options...
Cory Posted June 14, 2022 Author Share Posted June 14, 2022 9 minutes ago, jedimatt42 said: Looks like the motherboard equivalent of the diode fix for the capslock/joystick up fix.. Thank you! Quote Link to comment Share on other sites More sharing options...
+Ksarul Posted June 14, 2022 Share Posted June 14, 2022 This is the perfect place to ask this type of question. Lots of interesting discussions about what was possible have resulted from past questions like this. 2 2 Quote Link to comment Share on other sites More sharing options...
Cory Posted June 14, 2022 Author Share Posted June 14, 2022 Given the tip from @jedimatt42, I found a previous post on the topic: And read the article on http://www.mainbyte.com/ti99/console/alpha_lock.html Does placing the diode on the motherboard save you from modifying the keyboard like this instructions from the mainbyte site: ... you must remove a part of the lead that originaly ran to from the alpha-switch and the connector 6 on the keyboard connector Quote Link to comment Share on other sites More sharing options...
apersson850 Posted June 14, 2022 Share Posted June 14, 2022 I'm still astonished TI didn't include this from the beginning. I could understand if they had removed the diode in the later reductions of all costs, when they tried to save millicents, but from the beginning? 1 Quote Link to comment Share on other sites More sharing options...
+mizapf Posted June 14, 2022 Share Posted June 14, 2022 This is a non-obvious glitch that you don't see in the schematics. So the design was done, and it seemed too late to change it. In the QI they actually fixed it. Quote Link to comment Share on other sites More sharing options...
Cory Posted June 14, 2022 Author Share Posted June 14, 2022 (edited) Curious whether the diode placement on the motherboard saves you from cutting the trace on the keyboard between the alpha lock and pin 6 on the keyboard connector. It seems to me that it would and would be a simpler modification. Is that true? I guess "simpler" is a bit of a subjective term since you have to desolder a component to squeeze the diode in. Edited June 14, 2022 by Cory Quote Link to comment Share on other sites More sharing options...
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