Tator Posted January 7, 2013 Share Posted January 7, 2013 Hi, I built an HdX PCB to modify an RS232, Fred Kaal design, (http://members.ziggo.nl/fredgkaal/index.html) and now I´m ready to mount it in the original RS232 but have some doubts regarding the installations of the switchs and would like to check if somebody already did it and can help me. 1) According to the schematic view (http://members.ziggo.nl/fredgkaal/Pics/ti99hdx/ti99_rs232_dsr_ram.gif) the trace that has to be cutted is the one that goes from pin 8 of the 74LS21 (u17) to pin 1 of the 74LS125 (u6), but in the picture of the modifier RS232 card (http://members.ziggo.nl/fredgkaal/Hardware/hw_ti99hdx_card_rs232.html) the trace that is cutted is pin #3 of the 74LS125 (u6). 2) Switch 1 (SW1) is added to be able to close the previous cutted trace and also pin #1 of the 74LS125 (u6) is connected with a 10K Resistance (R6) to +5V, is that correct? Any suggestion on where to take those +5V? Could pin12/13 of the 74LS21 (u17) be used? I´ll appreciate your help! Kind regards Sebastian Magnasco Quote Link to comment Share on other sites More sharing options...
+retroclouds Posted January 9, 2013 Share Posted January 9, 2013 Hi Sebastian, quick question; Have you tried to contact Fred Kaal via email ? He's not on this forum, but he can be contacted via email. Quote Link to comment Share on other sites More sharing options...
Willsy Posted January 9, 2013 Share Posted January 9, 2013 I have an HDX card that was built by Fred. I can take a look at what he did. Quote Link to comment Share on other sites More sharing options...
Tator Posted January 9, 2013 Author Share Posted January 9, 2013 Thank you for your answers, I don´t have Fred Kaal email, does anybody knows in which email I can contact him? Thank you Sebastian Quote Link to comment Share on other sites More sharing options...
+retroclouds Posted January 9, 2013 Share Posted January 9, 2013 PM sent. Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted January 22, 2013 Share Posted January 22, 2013 (edited) I just built one as well. Had zero problems getting it running. https://sphotos-b.xx...411104870_n.jpg is my board with the hacky wiring You can see i just cut the lead of the chip where the interrupt is off the board and bent it up and attached a wire to it and the the other side of the switch is just wired to the test point on that same trace down near the peb connector (because I'm lazy and soldered it to the easier spot The other three wires were soldered to chips and the other test point per his instructions at http://members.ziggo.nl/fredgkaal/Pics/ti99hdx/ti99-rs232-complete.gif And the resistor removed at R19.. Greg Hi, I built an HdX PCB to modify an RS232, Fred Kaal design, (http://members.ziggo...kaal/index.html) and now I´m ready to mount it in the original RS232 but have some doubts regarding the installations of the switchs and would like to check if somebody already did it and can help me. 1) According to the schematic view (http://members.ziggo...232_dsr_ram.gif) the trace that has to be cutted is the one that goes from pin 8 of the 74LS21 (u17) to pin 1 of the 74LS125 (u6), but in the picture of the modifier RS232 card (http://members.ziggo...card_rs232.html) the trace that is cutted is pin #3 of the 74LS125 (u6). 2) Switch 1 (SW1) is added to be able to close the previous cutted trace and also pin #1 of the 74LS125 (u6) is connected with a 10K Resistance (R6) to +5V, is that correct? Any suggestion on where to take those +5V? Could pin12/13 of the 74LS21 (u17) be used? I´ll appreciate your help! Kind regards Sebastian Magnasco Edited February 11, 2013 by arcadeshopper Quote Link to comment Share on other sites More sharing options...
CantStopClicking Posted January 28, 2013 Share Posted January 28, 2013 PM sent. Could you share the photos of your board? This is one of my next projects. I'd love to see another working example. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Tator Posted January 28, 2013 Author Share Posted January 28, 2013 Of course, I´m attaching the pics, aswell as some tips based on my learnings building the project that may help you. - Please note that Fred updated the schematics to include with or without switch option. - I did a PCB, but if you are not familiar with doing this or can´t get one done I would recommend to use a standard perforated project board. Drilling the holes at the precise location for the IC socket and the connector is not very easy. . - I kept half of the original metallic clamshell and just added a couple of nuts and washers to the original nuts to still have it as a heat disipator. ( see pics) - I couldn´t find small switches that can fit nicely in the card so I decided for a jumper-type solution using a pair of onboard male plug connectors. ( see pics). Hope this helps. Any doubt, just let me know. Best Sebastian Quote Link to comment Share on other sites More sharing options...
Stuart Posted January 28, 2013 Share Posted January 28, 2013 A Maxim DS1210 (http://datasheets.maximintegrated.com/en/ds/DS1210.pdf) would make a good replacement for all those diodes, transistors and resistors in providing backup power for the RAM. It's a pretty foolproof little 8-pin chip that I've used with no problems in the past. Quote Link to comment Share on other sites More sharing options...
CantStopClicking Posted January 31, 2013 Share Posted January 31, 2013 Tator: Sweet! Thanks for posting the pic's and sharing your comments. Stuart: That's a cool little package there (DS1210). I could see that getting implemented in a SuperCART. I just wish I knew enough to engineer something with it! Is there any interest in a group buy on a PCB order for the HDX project? And probably more important, is there any cost benefit in a group buy? If so, I'd be happy to get the ball rolling. Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted February 11, 2013 Share Posted February 11, 2013 Note, Fred released a DSR and HDX pc side update today. http://members.ziggo.nl/fredgkaal/Software/sw_ti99hdx.html#ti99hdx the new server is not compatible with the old DSR so you should update the DSR first. I am already ordering a small run of boards if they are good quality-wise/work right I plan on a pre-order group buy for more. Greg Tator: Sweet! Thanks for posting the pic's and sharing your comments. Stuart: That's a cool little package there (DS1210). I could see that getting implemented in a SuperCART. I just wish I knew enough to engineer something with it! Is there any interest in a group buy on a PCB order for the HDX project? And probably more important, is there any cost benefit in a group buy? If so, I'd be happy to get the ball rolling. Quote Link to comment Share on other sites More sharing options...
CantStopClicking Posted February 11, 2013 Share Posted February 11, 2013 Note, Fred released a DSR and HDX pc side update today. http://members.ziggo...dx.html#ti99hdx the new server is not compatible with the old DSR so you should update the DSR first. I am already ordering a small run of boards if they are good quality-wise/work right I plan on a pre-order group buy for more. Greg Definitely count me in! As "they" say.... +1 -Dano Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted February 28, 2013 Share Posted February 28, 2013 Definitely count me in! As "they" say.... +1 -Dano I got in my small run of boards and just built one last night, works great. Anyone else interested lmk and I'll add you to the count for the next order. Dano's already on it Greg Quote Link to comment Share on other sites More sharing options...
CantStopClicking Posted February 28, 2013 Share Posted February 28, 2013 Dano is super happy! Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted March 11, 2013 Share Posted March 11, 2013 (edited) I got in my small run of boards and just built one last night, works great. Anyone else interested lmk and I'll add you to the count for the next order. Dano's already on it Greg http://www.arcadesho...id=21147033 is the pre-order for the next run of boards. There's a google wallet checkout link in the cart for cards. Edited March 11, 2013 by arcadeshopper Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted March 21, 2013 Share Posted March 21, 2013 http://www.arcadesho...id=21147033 is the pre-order for the next run of boards. There's a google wallet checkout link in the cart for cards. Pre-order is now closed.. will be ordering the boards tomorrow 3/22 eta is 3-4 weeks Greg Quote Link to comment Share on other sites More sharing options...
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