Gary from OPA Posted September 26 Share Posted September 26 Has anyone studied the 99/22 schematics and mapped out unused logic gates like on the 74, 00, 32, etc. on the original 4A there was a number of them. I was wondering if Dan left any unused and if so did he tie them to ground or vcc, depending on what revision of 4A motherboard, some were left floating, others were grounded. Just thinking about my upcoming modifications I want to test. Would be handy to know what I can use that there already and available. 1 Quote Link to comment Share on other sites More sharing options...
RickyDean Posted September 26 Share Posted September 26 @stevee671 How are you solving the issue with the IC that will be setting under an installed cartridge, as talked about in the TI-99/22 issue thread? Quote Link to comment Share on other sites More sharing options...
+OLD CS1 Posted September 26 Share Posted September 26 5 hours ago, RickyDean said: Man, that shows that someone is watching, waiting to see if they can make a buck from us!! Entrepreneurs key an open eye for opportunity to provide a worthwhile service for worthwhile prices. 2 Quote Link to comment Share on other sites More sharing options...
stevee671 Posted September 27 Author Share Posted September 27 3 hours ago, RickyDean said: @stevee671 How are you solving the issue with the IC that will be setting under an installed cartridge, as talked about in the TI-99/22 issue thread? It's going to need an extender or you can use the 90 degree from a 4A. That was quite a surprise when it was brought to my attention. How do you miss something like? That GROM port is a pretty important part of the 99. Quote Link to comment Share on other sites More sharing options...
Gary from OPA Posted September 27 Share Posted September 27 (edited) 5 minutes ago, stevee671 said: It's going to need an extender or you can use the 90 degree from a 4A. That was quite a surprise when it was brought to my attention. How do you miss something like? That GROM port is a pretty important part of the 99. The 90 degree one from a 4a flips the odd and even sides, so it would NOT work, unless originally the board was designed for it. If you remove the cartridge shell it works, bare board only install! Edited September 27 by Gary from OPA Quote Link to comment Share on other sites More sharing options...
stevee671 Posted September 27 Author Share Posted September 27 Oh! interesting. I didn't know it was flipped! Quote Link to comment Share on other sites More sharing options...
Shift838 Posted September 27 Share Posted September 27 for everyone that has a 99/22 board and wants to build it. I have extra 74LS379's and 574's. PM me. Quote Link to comment Share on other sites More sharing options...
Shift838 Posted September 28 Share Posted September 28 I only have 379s left. 1 Quote Link to comment Share on other sites More sharing options...
RickyDean Posted 12 hours ago Share Posted 12 hours ago Not an issue, but a question. I have some resistors that came in for this project that are the mini 1/4watt style, not the full size 1/4 watt style. Is is still acceptable to use these in this project, will they hold up to the electrical load? Quote Link to comment Share on other sites More sharing options...
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