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Quickie

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  1. Hi all, I hope that I will be able to check components and traces located between LM1881N pin 1 and the sync pad tomorrow, and as @ChildOfCv states, most probably one of the resistor edges could not be properly solded to the pad. If that is the case I expect to get rid of the current interference that is being presented. @Papalapa The results on the Coleco are very promising, so, having in mind that the source of inspiration of this particular board was originally designed for a Ti-99/4a I have no doubt that it will work as well Don't worry, I'll keep you posted in VdR
  2. Weeell!! I did some try/catch and soldered directly the sync pin of the RGB DIN connector to the LM1881N pin 1. This is what I get: It's stable, altough there is some noise... this is almost there!
  3. Hello, Apologies for not being able to update this earlier, but it has been impossible Well, I had some time to do the testing, and although I guess that I would have done something bad, there is something interesting: - This is the screenshot of the Sync pad of the RGB PCB on the Oscilloscope with AutoSet scale: The same wave from the same pad of the RGB PCB , but this time with the scale defined after adjusting the probe and with measured data (seems that there is no signal there...): And finally I captured the signal on the LM1181 pin 1 (Sync Output), which looks completely different: Alexis, the creator of the TMS9929A RGB and Component adapter of Hackaday (Kudos for him!) has gently advised me that perhaps removing the 82 ohm resistor on the Csync output could enlarge the sync pulses and make them recognizable for my TV. To be sincere I don't know if after the data I provided that explains it all, but I'll give a try...
  4. Hi, I insulated the 4066 in this unappropiate package with hot glue from the passive components underneath. Good point I can recheck there if there might be some undesired contact underneath. I do have an oscilloscope. I was advised that I could check the sync wave on the LM1881 and on the Sync pad. For me that seems like a good action plan Let me grab some time and I post both results. Regards
  5. Well, I've tried your suggestion, however that trace is so tinny and so near to a resistor that I traced both sides of it (U4:2 to U1:3) and cutted it on the base of U4 pin 2, where there is somo more space, soldered the 0.1uF cap on the U4 pin 2 leg and soldered a wire on the other end of the 0.1uF cap: Here the pad cutted: And here with the capacitor soldered and wired to U1. Not the best soldering job on the world, but does its job (and there are no shorts): Although it does not work fine yet it seems to present the image more continuously: It's almost there...
  6. Yeah! Big Thanks for your time and help! I will try it asap and post here the result. I remember seeing that project back in the day in Hackaday, but I completly forgot about it and I did not associate it with this.
  7. Hi, I will try to check with detail the PCB I made and the soldering to check that there isn't any short, however when I soldered the components and installed the mod on the PCB I double checked that there wasn't anything unexpected. In regards of the other NTSC board I have one half-done (I miss the resistors and other passive components). But I discontinued it when I realized that it was only valid for NTSC machines. I guess that this is because the TI-99 (and the Colecovision) do use a different VDP on each region: TMS9918A (NTSC) vs TMS9929A (PAL) with their own specs. I thought that, being the PAL RGB mod an untested one perhaps the sync line could require of some extra adjustment by increasing the value of 75Ohm on Sync. In any case I've PM'ed @citrus3000psi to check if he can confirm this. Thanks for your help!
  8. Hi, Thanks for responding. I thought that -5V wasn't needed for anything else than the old RAM ICs. I read on another thread that the -5V could be required for the controllers, but that seemed to be another topic (or at least his author stated afterwards that should work fine without -5V). Since I can't edit again my previous post, here are the pictures (apologies): Update: I replaced the Z80 processor and it seems that the console is not so dead...
  9. Finally had the time to test Citrus' PAL RGB design and my Colecovision refuses to work at first try. This Coleco was an "untested" unit I bought and since I had no power supply I did some work before installing the RGB mod: - I managed to adapt a 12V3A DC transformer inside the case. That feeds a picoATX psu which provides the +5 and +12V. - I did the 4164 RAM Mod as I missed the -5V line (and wanted to ensure that the ram would be OK) And this was the result: Which finally ended in this: And unfortunately what I obtain when powering the console on is an intermitent black screen and sometimes some artifacts like this: In any case I do not consider the RGB mod to be the cuplrit. I am unable to tune the Coleco on the TV via UHF, so there must be something else By the way the voltages were measured and OK, the Z80 /RESET stays high when powering on and the RAM was tested. Regards
  10. Hi @rj1307, I would be interested in acquiring another cart (as I've already purchased from you in the past and I've been very satisfied). Thank you, and please, let me know how to proceed on the payment. Cheers
  11. Finally I've been able to do the assembly of one PAL ColecoRGB board. Unfortunately I ordered the 4066 on TSOP package and not TSSOP-14, so I had to do a workaround to have at least a proto finished. By the way citrus3000psi states that this board is untested and should be used on own risk. By the way I haven't seen anyone confirming that the PAL board works, so I'll cross my fingers...
  12. Declaring interest. Could you please check the price of shipping it to Spain? I have a Lynx II which needs a magnifier replacement, and this would be great. The non-working Lynx II adds more fun and challenge to the package to test myself if Iwouldbe able to fix it. Thanks
  13. Not yet, but I hope to test them in 1-1.5 months period. I panelized a batch of Citrus3000 psi RGB Boards 2 months ago, later ordered components to build at least 5 boards and stated to build them as I wanted to test it on my Colecovision and TI-99/4A PAL machines. How fun was to discover on the meanwhile that the TMS9918A and TMS9928A are completely different and while the first does composite out, the second does luminance and color difference. So I ended up with a batch of 5 ColecoRGB NTSC PCBs that I won't be able to use them and a batch of PCBs of the same variant. If anyone is interested, please, let me know, but have in mind that they are untested!. It was my fault, next time I should read the project details from tail to end Now I am decided to do a new PAL pcb prototype, among with the minidin header. Let's see if things goes better this time.
  14. Hi! I would like to buy one. Could you please add me to the list? Thank you!
  15. Hi ti99iuc, I live in Spain, and yes, I understood that you noted on your diagram that it was the connector side (lato spinotti) however, I think that being Samsung LCD TVs too picky with components perhaps there might be some additional passive component addition that could help to fix this problem (capacitors/resistors). Have tried to find out if there is some information about this topic elsewhere but couldn't find any interesting information, as this seems very specific (TI-99/4A Euro model). Cheers
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