Lambda Mikel Posted July 14, 2022 Share Posted July 14, 2022 (edited) Hello all, so my new-revision NTSC motherboard got the TMS-RGB, and the VDP was changed for PAL (->TMS 99929A). However, RGB image was black & white only. Please see pictures attached. We also cut wires L2 / L3 near the video DIN socket, but that made no difference (well, composite output was gone from the DIN then). What other mods might be required to an NTSC new-revision motherboard in order to get color? The monitor is fine and works perfectly - and in color - with other RGBs sources (e.g., Amiga 500, Amstrad CPC). Also, I am noticing that the audio is a bit faint and noisy now with that board. This might be unrelated to my failed TMS-RGB installation attempt, but I hadn't noticed this until I put the machine back together. I removed the TMS-RGB for now and put in the NTSC VDP. Color is back. Thanks for any ideas. Edited July 14, 2022 by Lambda Mikel Typo Quote Link to comment Share on other sites More sharing options...
Lambda Mikel Posted July 14, 2022 Author Share Posted July 14, 2022 PS NTSC composite video is fine without TMS-RGB, as shown here. Insert other media Quote Link to comment Share on other sites More sharing options...
Lambda Mikel Posted July 15, 2022 Author Share Posted July 15, 2022 (edited) Sorted, can be closed. Used an old-style motherboard and applied the TI mod. Without applying this mod, you'll only be getting B&W from an NTSC 99/4a. Simply swapping the VDP and installing TMS-RGB doesn't do it. Edited July 15, 2022 by Lambda Mikel Adding detai - typo 5 Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted July 15, 2022 Share Posted July 15, 2022 8 hours ago, Lambda Mikel said: Sorted, can be closed. Used an old-style motherboard and applied the TI mod. Without applying this mod, you'll only be getting B&W from an NTSC 99/4a. Simply swapping the VDP and installing TMS-RGB doesn't do it. thanks for this, added to the FAQ, prob you could have used the NTSC version of the chip (9928) to avoid the mod Quote Link to comment Share on other sites More sharing options...
Lambda Mikel Posted July 15, 2022 Author Share Posted July 15, 2022 (edited) 1 hour ago, arcadeshopper said: thanks for this, added to the FAQ, prob you could have used the NTSC version of the chip (9928) to avoid the mod I don't think so. The TMS-RGB didn't work with the NTSC VDP for me. Showed garbage on RGB. Also I wanted a PAL TI. So, one can leave the NTSC 5pin DIN installed, but the audio is buzzing. Now, I also needed to route another audio cable. That solved the buzzing and noise issue. Maybe interference from the video or insufficiently shielded cable? I have a 4 RCA socket to DIN5 cable (same I usr for C64 etc.) And was only going to use only the audio line but the video buzzing was very audible. Yes, I used the right line of the cable ? Dedicated mini stereo socket fixed the audio. Edited July 15, 2022 by Lambda Mikel Typo 1 Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted July 15, 2022 Share Posted July 15, 2022 (edited) 5 hours ago, Lambda Mikel said: I don't think so. The TMS-RGB didn't work with the NTSC VDP for me. Showed garbage on RGB. Also I wanted a PAL TI. So, one can leave the NTSC 5pin DIN installed, but the audio is buzzing. Now, I also needed to route another audio cable. That solved the buzzing and noise issue. Maybe interference from the video or insufficiently shielded cable? I have a 4 RCA socket to DIN5 cable (same I usr for C64 etc.) And was only going to use only the audio line but the video buzzing was very audible. Yes, I used the right line of the cable ? Dedicated mini stereo socket fixed the audio. the 9918a? or 28a? the console originally had an 18.. composite.. https://en.wikipedia.org/wiki/Texas_Instruments_TMS9918#TMS9918A_and_TMS9928A Edited July 15, 2022 by arcadeshopper Quote Link to comment Share on other sites More sharing options...
Lambda Mikel Posted July 16, 2022 Author Share Posted July 16, 2022 Both the beige and the silver had an 18 installed. I checked TMS-RGB first with the 18 in the beige 99er, and got RGB video garbage. Plugged in the 28A and got B&W RGB. Then found the mod, but didn't apply it as it seemed to apply to the black&silver old revision board. I hence reverted the beige into original NTSC condition, and modded the silver TI with the old style board instead. I haven't checked NTSC VDP (18) with TMS-RGB in this one, as it already had failed in the beige with the same 18 NTSC VDP. Hence, I went straight for PAL 28a. Discovered that it was B&W. Applied the TI mod. Got color. Happy I didn't unsolder the DIN socket if I ever want to revert it back to original NTSC, it's easy to do. I added RGB DIN 6 socket for Amstrad CTM RGBs monitor, and an extra mini stereo to fix the audio droning. 2 Quote Link to comment Share on other sites More sharing options...
Lambda Mikel Posted July 16, 2022 Author Share Posted July 16, 2022 (edited) So, in my reply above, replace 28 with 29... see picture. My NTSCP VDPs were 18's. The PAL one is 29A. Edited July 16, 2022 by Lambda Mikel Typo 1 Quote Link to comment Share on other sites More sharing options...
+arcadeshopper Posted July 16, 2022 Share Posted July 16, 2022 16 hours ago, Lambda Mikel said: So, in my reply above, replace 28 with 29... see picture. My NTSCP VDPs were 18's. The PAL one is 29A. was gonna say! 1 Quote Link to comment Share on other sites More sharing options...
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