repetto74

I have modded today the 6 switch Atari 2600 with the small PCB adapter provided by TheFuturewas8Bit (thanks to them ). I do have an output with color and sound but I would like to be sure that this is the best result I can have with composite. I did the mod following instructions closely, so removed the RF modulator, resistors, transistor and the red coil then wired everything up. As per the pictures taken from an LCD and a CRT TV I can see that colors are a little bit too bright and that there are those annoying vertical shadows lines across the screen. Can this be fixed to improve image or maybe someone can suggest me to check the mod if something may be not correct? There is a resistor I can tweak with a screwdrive I think to adjust color. Thanks Rick

Hi Guys, The cassette recorder is old yes, dated around beginning of the 80's so it should be fine and ouputs mono only. I will build this cable and test it then to check it is properly working . Thanks Rick

I would like to build the cassette deck cable to hook the Ti99/4A to the cassette tape recorder. I have a link to the schematic here : http://mainbyte.com/ti99/hardware/cables/cassette.html so MIC and Speaker will need a 3,5mm MONO audio jack but what about the Remote port ? Which kind of jack do I need for this input? This is smaller than the 3,5mm input. Thanks Rick

Hi Apersson850, Ok now I understand what you mean. Well I would say that considering the fact that the CPU can address 32k of ram maximum I would say that this will be enough for me. I am just a newbie for what concerns TI99/4A and have a lot of work to do in order to use the machine correctly. Actually I need to build a cassette tape cable to use with the cassette recorder. Then I can consider modding the total ram to 32k (found this tutorial https://www.harmlesslion.com/text/TI%2032k%20Mod.pdf)and then maybe later on I may consider a nanoPEB if this piece of electronic is still available for sale :-)

Yes the TV can handle RGB as I connected a Spectrum 128k +2 Grey model which comes with a RGB video output through a SCART cable. Any tutorial on how to do this also?

Hi Apersson850 Any link for a tutorial explaining how to mod the TI99/4A to 64K ?

Hi Stuart Thanks a lot for the schematic. Actually I have various working 8bit machines I would like to output to the same HD TV and with the best option possible. Wherever an S-video mod was possible it was done (Atari XL, VIC-20), composite is the second option when S-video is not possible (ZX Spectrum). The C64 and the Spectrum 128k are respectively S-video and RGB native. I am using a video upscaler AV/S-Video to HDMI which gives a really nice conversion to the HDMI TV. A composite mod to the TI99/4A will be a very good result then :-)

Hi Arcadeshopper, Nope the RF modulator is not the one with the SCART (PERITEL) output for the french market. I got this from an italian e-bayer and the modulator has been manufactured in Italy also but will need a TV antenna input. To Sinphaltimus : thanks for the greetings and will read closely the thread :-)

Working for me also on 10.12.6 !. Thanks that rulez!

Hi to all, I am an happy owner of a PAL TI99/4A since today (I am located in Europe) :-). The machine comes with the RF antenna cable with the big RF PAL modulator and the 6 pin DIN video socket output. I can test this with an old CRT TV I still have but I would like to know what are the best video modding options available to increase video output? Composite, S-video? Any tutorial? Besides that are there also hardware mods available to increase total memory or to improve the machine performance in general? Sorry I am really a noob with the TI99/4A so trying to sum up what is possible to do. Consider that I do have soldering and basic electronic skills + all tools required for the job :-) Many thanks, Rick

Ok looks sorted out now. I had cleaned the unit, added some solder on the swiches solder joints. Now I do have a B&W image for a few seconds then back to color..weird. Anyway I am waiting for the AV composite pad modification to give this machine a video boost!

So I have disassembled the unit. I have read that first thing to do is to turn the pot to fine tune colors. The pot is the white one (regulated resistor) or the red coil in the middle?

So I managed to tune the TV to the have a display. Poblem : -image is in black and white even with the switch TV TYPE set to color (the TV is a color one of course). All other functions seem to work and joysticks will work. I did select a manual + a fine tuning and I did get colors but the problem is that it will return to B&W when turning off the Atari and switching it back on.

Hi guys, I picked up today an Atari 2600 model CX-2600. I had this for few bucks without any guarantee it is working. Hi hooked it up to a standard CRT TV with the RF antenna input at the back but I do not know how to tune the TV. The console does not have a power up light so I cannot be sure that power is applied when turning on the power switch. What should I check first to ensure that the board is correctly powered? I was maybe thinking to go for the composite mod before and check if there is an output on the TV through the video composite inputs. There is also a Channel Select switch at the back for A or B channel selection. What does this mean? Any suggestions? Rick

10 ; 20 .OPT OBJ 30 *= $8000 40 CLR LDA 53770 50 STA 53274 60 LDA 53770 70 STA 53272 80 JMP CLR Yep this will give like the classic loading pattern of a C64 tape . How is that big difference? Ok I see, the VBLK act like a delay so when using the shadow register the video refresh is slower.

Ok guys thanks a lot for your advices I am a beginner in ML coding I need to get deeper into that and I know there are always better ways to code in ML for optimal execution :-)

Ok guys thanks a lot!! I have pdf copies of Analog magazine so I will put my nose into them and study this a little bit closely . And thanks also for the book reference, looks good to have BASIC graphics and then a switch to ML

Hi Shanti77, I am not an expert on ML codings I am learning honestly. Can you explain better this technique of shadow registers?

Dumb I am !!! Thanks Mapa

Hi have tried to code a small routine to cycle through border and background colors : 10 ;******************************* 20 ;* BACKGRND AND BORDER COLORS * 30 ;******************************* 40 ; 50 .OPT OBJ 60 *= $8000 70 CLR LDA 53770 80 STA 712 85 JMP DELAY 90 LDA 53770 0100 STA 710 0105 JMP DELAY 0110 JMP CLR 0251 DELAY 0252 LDX #15 0253 LDY #0 0254 LP1 DEY 0255 BNE LP1 0256 DEX 0257 BNE LP1 0260 RTS Actually I have a different behaviour when testing it with M65 DDT command : - without the delay loop the program will cycle colors at high speed in an endless loop - with the delay subroutine the program stops immediately and will display only one set of colors Cannot understand where I am wrong here. I would like to have colors being displayed slowly in an endless loop.

Ok guys thanks a lot for the clarifications! Actually I am starting with ML coding on ATARI and I would consider myself as a noob. I am going through some basics books like ATARI ROOTS to better understand how ML works and would like to play more with graphics in particular. I understand then that most of the PMG basic routines are made with POKES but was for example asking myself how do you code in ML a change of graphic mode?

Hi ZZIP, Thanks I have this book but it is only referring to coding in BASIC. I would like to have a guide on how to code graphics in ML on the ATARI.

Does anyone have a good book reference of machine language routines to learn how to code PMG and Atari Graphics in general ? I have some books in my library but only limited to BASIC coding which is quite a pain I have to say. :-(

Copied then Many thanks for your explanation on this !

Ok Reveng this sounds more clear to me . So the BNE is referring to the CMP of X and Y registers to the #0 value which is set by default and as you said there is no need to code a CMP #0.