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repetto74

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Everything posted by repetto74

  1. The bodger in me wants to suggest reassembling it in the case with a bit of folded cardboard positioned just where you need to apply pressure ...  I do not really catch what do you mean here? You mean putting cardboard to simulate the finger pressure? How can I do that ?
  2. Hi Dragonstomper, Yes the clock generator is socketed and was initially suspecting a bad socket so desoldered it properly and replaced with a precision socket before I made this video so no changes. Moving the PSU wires does not make any difference, I have checked voltages and they are all fine + applied fresh solder on the wires connection. Will try to clean the VDP socket with contact cleaner then.
  3. Hi Dragonstomper, This video speaks more than words on the issue I have. Putting pressure with my fingers on top of the clock generator and on the opposite edge of the board (close to the GROMS and Sound generator) will make the TI99 to boot up normally. As I release gently the pressure I start having the video getting garbled and when I totally release pressure than it goes black. Putting pressure again will make the TI99 boot sequence to start again (beep sound) so I do not think this is just related to a bad video connection. There is a cracked joint or track somewhere in the area where the finger pressure is bending the PCB. At first glance I cannot see anything from the solder side of the PCB. <iframe width="560" height="315" src="https://www.youtube.com/embed/YMzSjsBfFKI"frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
  4. Test are done without the cartridge port. I have some soldering skills and tools required so O would like to try to fix it :-). Thanks for the proposal but I am located in Europe and shipping costs will be far too high.
  5. Little update. I found that when pushing hardly on the left side of the PCB board and firing up the machine then it will boot properly on the welcome screen! If I leave my finger then it goes black again. I tried then to wiggle gently the PCB and can see distorsions on screen. Sometimes when I put some pressure on the right side of the PCB then the video come back again. Weird and probably related to a broken track or bad solder joint? How can I proceed to find it out?
  6. Hi Guys, Reposting here as first request was posted on wrong section. ******************** Today I had to open my TI99/4A because there were a lot of video glitches on screen (top half part of the screen with a pink overlay and sometimes a lot of video glitches popping out). It turned out to be the cart connector making bad contacts. After a good cleaning and a test on the fly all seemed to work again but after re-assembling the machine then the TI99/4A will not power up anymore :-(. All I have is a black screen(no sound). I am maybe suspecting the power switch contacts having gone bad. How can I test it and how can I clean the switch? Is there any reference for a suitable replacement? PS : The machine has the 32K mod hard wired in it and done by myself so could be also that a bad soldering somewhere is preventing a good start up. Thanks Rick
  7. Just a black screen. I do see a white band glitching half a second but no boot and no sound.
  8. Hi Guys, Today I had to open my TI99/4A because there were a lot of video glitches on screen (top half part of the screen with a pink overlay and sometimes a lot of video glitches popping out). It turned out to be the cart connector making bad contacts. After a good cleaning and a test on the fly all seemed to work again but after re-assembling the machine then the TI99/4A will not power up anymore :-(. All I have is a black screen. I am maybe suspecting the power switch contacts having gone bad. How can I test it and how can I clean the switch? Is there any reference for a suitable replacement? PS : The machine has the 32K mod hard wired in it and done by myself so could be also that a bad soldering somewhere is preventing a good start up. Thanks Rick
  9. Hi Level42 in case here were I found it https://m.thomann.de/be/index.html
  10. Hi Level42 Here is a picture of one of the 100 uF cap I removed today. There is no name on it but if you zoom the picture there is a small logo and you may guess the brand Cheers, Rick
  11. Hi Level42, I will open the PSU tomorrow and let you know the brand no problem . Yes the replacement caps are good quality ones I bought from my local electronic reseller here.
  12. Hi Level42, Good! I will replace the three of them for precaution then. I have them in stock here with me so it will be a quick job to do :-). Thanks a lot. Rick
  13. Hi Level42, I have this picture here if that can help otherwise I may open the PSU case again and take some better pictures. As you can see I do not know if the two 100uF caps are or not polarised.
  14. Hi, the PSU of my 800 XL is this one below I am glad to hear it is a quality one compared to others. I have checked the PSU pcb recently and did not noted anything suspicious but was thinking to replace the tree elec caps as a precaution. I have a doubt concerning the two 100uF 25V caps as I am not sure if they are or not polarised. Both caps have a white band on one side so I assume this is to identify the negative lead? It is the first time I see caps with this odd marking. Thanks Rick
  15. Hi, I have a 800XL with this PSU and glad to hear it is a quality one compared to other. I have checked the PSU pcb recently and did not noted anything suspicious but was thinking to replace the tree elec caps as a precaution. I have a doubt concerning the two 100uF 25V caps as I am not sure if they are or not polarised. Both caps have a white band on one side so I assume this is to identify the negative lead? It is the first time I see caps with this odd marking. Thanks Rick
  16. I will try to dig out some Atari disks somewhere and test the drive with them .
  17. Hi Nezgar, I formatted again the diskette after the speed adjustment and you were right. All tests passed . Thanks a lot the 1050 is back to business!
  18. Hi 1050 FLOPOS looks very interesting. So this is a 4K OS to be burn into ideally 2732 eprom or can I use any 27c256 or 27c512? (merging the 4k program as much time as there is room into the eprom). Are they pin compatible?
  19. Was formatted once before running the diag test and used a couple of time already. The disk will boot also into DOS.
  20. I will try to clean again the r/w mech and lub the rails again + stepper motor. Keep you posted :-)
  21. Hi Guys, So I have tuned the drive speed to a nice 208,1 ms but all test are ok except the Head Step/Settle which still fails. Rails are lubed and head is cleaned with IPA. If I want to boot the formatted diskette to DOS it will just read and load fine with no problem at all. Considering this drive as working unless there is something more I can do to clear the failure.
  22. No adjustment done yet. Speed is actually at 210 where it should be ideally at 208. This is the next thing to do. The blank disk I formatted was already a single with option P from DOS 2.5.
  23. Is there an option in DOS 2.5 for that? P option will format SD I think.
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