macdlsa Posted August 3, 2014 Share Posted August 3, 2014 Hi there. A good friend of mine, who worked as former reporter for italian video game magazines of the 80 / '90 and collector of all kinds of consoles and home computers, asked me to perform some very specific mods on one of his many NTSC Heavy6ers . Since I had my PAL L6 from the beginning of the 80s, though, some of you know, I also got some NTSC cartridges besides PALs, I've never thought to do any type of mods on it, even if I confess that I do mind of having a NTSC VCS or 2600, of course to modify it just to be able to properly display NTSC carts' color palette! That said, this friend is askin' me to make the following changes : > video output - composite video on RCA pin-jack and separated chroma/luma on suitable connector > audio - in stereo simulated mode ; installation of two speakers, in the typical "slits" of the H6 (and also L6), with their "deidcated" small audio amplifier ; ability to "switch" between internal sound system and pin-jack RCA audio outputs to also been able to use an external amplifier. I'm not exactly a novice about using the soldering iron, but even I do not think that build tube audio amplifiers is comparable to this, I think I will read up WELL all the work which should be done to achieve such a (complicated) purpose . As for the audio issue, external mode aside, I believe that owning a H6 as it would have been intended in '76 before they decided to "exclude" an internal audio system, could be something even commendable ! A bunch of stereo digital audio amplifiers are available today, of course with performance definitely not "exciting" but with very little dimensions, cost, current consumption and working with a 9V supply voltage without having the need of further voltage regulators... then, in my opinion, they're kinda' perfect for this purpose. Obviously I would need to make some calculation about current absorptions and so do a "drift" on the power connector in order to "bypass" the VCS' 7805 and give power directly to the audio amplifier with the 9V adapter, which obviously could not be the original one... I know a good stabilized switching 9V/2A PSU should be fine for sure. In conclusion, what I can see on the web about those various mods on H6 is rather confusing to me (sorry ... maybe it's a bit 'of atherosclerosis .. ) so I was wondering if someone could do a little "update" here (but I know it would be much better to do it directly on a dedicated thread on the site), maybe with plans and any possible PCB ready for installation on H6 currently available on the market, with regard to the two CVBS + S-video mods and simulated stereo audio... Obviously, I would think at all the rest (internal amplification and eventual switch for the int/ext audio) in a later time ... If you have any suggestions, links, or even want to RE-talk about these changes ... thanks in advance ! Marco Quote Link to comment Share on other sites More sharing options...
macdlsa Posted August 5, 2014 Author Share Posted August 5, 2014 (edited) Ok, we decided to buy an AV mod board from "electronicsentimentalities", but it has no simulated-Stereo. I saw a simulated-Stereo modding on YT but I didn't see any schematics for this. Perhaps it should be simple, watchin' on the small number of components used for this purpose... Does anyone have clues about this scheme ? Edited August 5, 2014 by macdlsa Quote Link to comment Share on other sites More sharing options...
ApolloBoy Posted August 7, 2014 Share Posted August 7, 2014 Ok, we decided to buy an AV mod board from "electronicsentimentalities", but it has no simulated-Stereo.Yes it does actually, it's got two separate audio outputs for each TIA channel. I'm assuming that's what you meant? Quote Link to comment Share on other sites More sharing options...
macdlsa Posted August 7, 2014 Author Share Posted August 7, 2014 (edited) Since, as I said, I am not an expert in console moddings ( only few small repairs ), I had wrongly attributed to the "SIMULATED stereo" that particular modify, as the title of the thread says, capable to "restore" the H6 audio at the state they intended before the marketing... when, instead, it is the most common separation between the two audio pins of the TIA, one of which is also "dedicated", in addition to the relative monaural soundchannel, also to the two noise/square waves generators ! My mistake was given mainly by the fact that me and friends saw some PAL VCS' with a more complex mod that also introduces a chip able to perform an audio in stereo SIMULATED and / or even a kind of "surround" ( do not ask me "how" because I really don't know ). Edited August 7, 2014 by macdlsa Quote Link to comment Share on other sites More sharing options...
macdlsa Posted August 19, 2014 Author Share Posted August 19, 2014 Hi. At this point, THREE H6 are in the house of Marco Miccoli, a friend of mine and great collector/technician... he's goin' to clean and "restore" their chassis and fix some issues on the mainboards, just before we could mod them all . Quote Link to comment Share on other sites More sharing options...
+SpiceWare Posted August 20, 2014 Share Posted August 20, 2014 On the NTSC TIA there are 2 pins that output audio, one for each channel. When modding an NTSC Atari, one channel is sent to the left speaker while the other is sent to the right. The PAL standard required an extra signal to be generated by the TIA. Since all TVs at the time were mono, Atari just merged the output of the audio to a single pin, and used the other pin for the extra signal that PAL required. I suspect the "simulated stereo" mod was done to a PAL Atari as it's impossible to get stereo out of a PAL Atari. You can see the pinouts in the first post of this topic. The NTSC TIA has audio on pins 12 and 13. The PAL TIA has audio only on pin 13, pin 12 was repurposed for the PAL-S signal. Quote Link to comment Share on other sites More sharing options...
macdlsa Posted August 20, 2014 Author Share Posted August 20, 2014 (edited) Hi Darrel and pleased to hear you again ! Yep, I already saw both NTSC and PAL TIA pins layout and also know that some pins which were normally "used" by the NTSC were repurposed to adapt the PAL TIAs for been compatible with the various PAL-B , PAL-S etc. TV systems... So, for a PAL VCS/2600 it's impossible the stereo-out as it also is impossible to come out with a Separate-Video signal (while NTSCs of course can). I saw (and so "hear") some clips on this YT channel [ https://www.youtube.com/channel/UC_QO04tteYy160P-o5ITQdA ] but I'm terribly disappointed for the "echo" DSP-generated audio effect ! The thing I (we) still haven't see (hear) ANYWHERE is the "simple stereo" mod for PAL consoles: the main (and pretty good) site of those german guys whose made that "simulated-stereo mods" offers a nice configurator in which we could "setup" our console or even buy from them a pretty refurbished and already one [ http://www.konsolen-mod.de/en/index.html ].I suspect they use something else than a DSP IC (maybe an INTERNAL modding of the TIA ?...), but since I did not listen to that simple-stereo I could say almost nothing... I'm already discussing about that "original H6" question on FB in a group called " l'Alba dei Videogiochi " ( "Videogames Dawn" )... if you want to join us we'll be proud to have you among us !!! Best regards, Marco Edited August 20, 2014 by macdlsa Quote Link to comment Share on other sites More sharing options...
macdlsa Posted August 23, 2014 Author Share Posted August 23, 2014 Ok, boards have just been delivered here . ... just waiting for Marco and Carlo, next week, to spend a nice "Atari day", get the three H6 and start some modding works... Time to heat up my soldering iron (which is cold since the last tube audio amp I built... almost 2 years ago ...) ! Quote Link to comment Share on other sites More sharing options...
macdlsa Posted September 13, 2014 Author Share Posted September 13, 2014 ___Update___ I set up two of the three H6 with external plugs, while the other one will have the three RCA+S-Video cables comin'out "directly" from the original RF cable hole. First of all (but I expected it) the plastic of the Heavy 6 chassis is SO thick, while the RCA and ESPECIALLY the S-Video plugs threaded bolts are short... Since I do not have specific drills to adjust the thickness of the hole in the plastic, I was forced to use a very peculiar system: I heated up two dots of steel with the oxyacetylene torch and then slightly made the "rush" to the holes, enough to fit all the connectors... then, they were all fixed with respective nuts and some cyanoacrylate . CVBS quality is pretty good, as I already seen in one of my 2600 PAL consoles, but the Separate-Video gives to the images a quality I never thought it was possible from such a '77 ( but better say '76... ) console !!! Of course we european Atarians couldn't have the privilege to have such a connection on our PAL consoles due to the different TIA construction/layout. This feature together with stereo sound makes these H6 SUPERLATIVE consoles ! I would not have ever imagined !!! In the **MOD_26** image ( the penultimate one ) I show up a strange thing saw in the switchboard of the 2nd H6 I opened ( the one with a different, green mainboard ). Maybe someone already lay his hands on this board, because I found the polyester capacitor ( underlined in the last image **"MOD_29** ) soldered between the 5V line after the power switch and the center hole, while it should have been connected to the ground... In fact the console didn't work at all. Well, I fixed this issue (human mistake, for sure) and also re-soldered all the pins of the flat-connector port on this board.2200uF power capacitor still has its correct values ( WOW ! It's a "low-ESR"... i would think to replace it and use it for audio purposes... ) and the others components are also good... then, no needs of re-cap or replacements . ____________________ I have just TWO "BIG" QUESTION, though : internal speakers "slots" accepts a maximum of 21mm diameter magnet and 10mm (circa) of speaker thickness... maybe Atari thought to include inside the H6 and L6 two of the same speaker which is inside the Pong console ? And with a "fixed-volume" (stereo) amp ?I ask it because:A> I still haven't found a compatible speaker ( beside micro-loudspeakers, which are really crusty, though ) B> I don't see any hole or even "predicted hole" in the chassis which was intended for the volume potentiometer shaft... Quote Link to comment Share on other sites More sharing options...
macdlsa Posted October 3, 2014 Author Share Posted October 3, 2014 Ok, mission accomplished ! I finally set the three H6 as Atari intended (or close to... ) ! The third console ( the one without the RCA and S-Video plugs ) is more "well-ordered" [ pic ] ... but it has a problem... I tried with Gremlins and Pole Position ( both NTSC carts ) and I get those issues : > Gremlins When it has to change to the 2nd level ( the one with the Gremlins' comin' down from their "eggs" ) the VCS resets itsel and come back to the title/selection screen http://youtu.be/uRA7C-C04ek > Pole Position Turnin' on the console it plays the "session completed" sound, title screen is replaced with the "playing screen" with kinda' "unfilled" background mountains; then it turns "normal", playin' as well as nothing was happened... http://youtu.be/uHkq8yMlInk Of course with the other two H6 NTSC and my PAL consoles, those games behaviours' are pretty normal... Anyone knows what could be happened to that H6 ? Quote Link to comment Share on other sites More sharing options...
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