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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: Tatsujin on March 24, 2007, 10:33:15 PM
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does someone know a guide for a complete s-video modification of the DUO?
i allready collected some pieces of information (rgb to s-video converter IC etc..) but never found a complete mod from the scratch to its working end.
here my researches about the CXA1645P IC with NTSC-circuit > http://www.gamesx.com/rgbadd/cxa1645.pdf
do i need a TTL converter for the Pin 10? from where i will take the external clock?
thx in advance
tatsu :)
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I've never seen a complete guide and doubt it even exists for public.
As the PCE's video processor has no output for croma and luma you'll have to use a RGB => SVideo IC (like the one you ment above).
I know D-Lite has done it before (with the help of matt from gamesx) and even modded some PCEs for forum members. I suggest contacting D-Lite if he can hand you out a draft.
If you're gonna build it by yourself it would be great to publish it to Lawrence for the public.
Rgds
herr-g
Btw. It's a damn mess that RGB is still such an alien in all those NTSC regions.
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Tatsujin, you need an LM1881 sync seperator IC to get an imput for pin10. http://www.selectronic.fr/includes_selectronic/pdf/NS/LM1881.pdf
You then feed the composite video signal from the duo into that.
I already built my own circuit, using a smd cxa1645. However, I did not finish it. I still need to input the sine wave to pin 6. I could not find any solid information on what type of oscillator I needed to use, or how to use a crystal. I found a digital IC that is supposed to be a replacement for oscillators, but havnt tried it yet.
In any case, a writeup of this would not be hard. The hardest part is finding the cxa1645s in dip package.
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I finally finished my CXA1645 based chroma encoder. I managed to squeeze the entire thing into a 4.5cm square project board. Video quality is EXCELLENT compared to the original composite video.
(http://files.myopera.com/grahf/albums/136150/chroma%20encoder%201.jpg)
(http://files.myopera.com/grahf/albums/136150/chroma%20encoder%202.jpg)
(http://files.myopera.com/grahf/albums/136150/duo%20svideo.jpg)
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wow, thx a lot for the pics grahf :D that's awesome!! may you have a complete shematic of your device to share? :)
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That's awesome, you should post that on Gamesx and get it added to their mods.
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That is indeed swell :D Boy do I wish I'd be able to see the difference in picture quality! =P~
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it's almost like a RGB signal, but not that clear in matter of contrast and colors. but nearly almost.
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I dont really have a schematic, I just worked off of the cxa1645 datasheet. I could have built it a lot easier If i used a bigger board. If anyone has any questions about building their own, check aout the datasheet first, then feel free to ask.
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Looks really good. If you decide to ever do another,do a step by step guide for building the encoder on here for people. Alot of people have problems with reading schematics but can go off of visual guides perfectly fine.
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Thanks for the compliments guys. I just wish everyone could get to see a PCE with decent video :) If only I knew where to get the CXA1645s in dip package (the bigger, through-hole ones). These surface mount ones are really hard to work with. On the sdm chip there are two pins of the chip for every hole on the project board. I just split each hole into two with a razor knife. Then removed the contacts on the next row to give myself some room. Also, I tried to arrange everthing so that it was small, and didnt use many jumper wires. If you dont care about this, it will make things easier.
I was thinking about just getting a custom PCB made if I decide to build another one. In the mean time, I may draw up some pictures that better explain what components have to go where on this encoder for those interested in tackling this as a project.
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To whoever eventually makes a schematic of this: you are my hero.
So is this mod pretty much as simple as providing the needed inputs as directed on the datasheet (not including the input from the crystal), then routing the output? If so I may have to try this out.
I wonder if there would be room for the s-video mod, a region mod, and composite output (RCA) in a regular old US Turbo Grafx-16? I guess I could always remove the RF modulator and some of the casing/shielding...
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I'll start drawing up a simplistic schematic in paint shop when I have time. Its not really hard to build, but people without experience in reading datasheets might have a hard time knowing what type of components to use and such. I'll see if I can clear some things up.
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Any help you can offer would be appreciated. In the meantime I'll try to figure things out myself and will make a schematic of my own. If I can figure most of it out maybe you can look it over and help me make some corrections instead of having to make a schematic yourself.
And if anyone else is interested I made an offer of $13.95 for a CXA1645M from a seller on eBay (the only guy who is selling these chips right now) and he accepted, so if anyone else wants to try the same thing you can probably get the chip for $20 even shipped.
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That would be awesome, I was going to pay someone to do mine but Mike said it was a pain in the ass to do Duos so I'd actually like to try and build one myself as a challenge, the only thing I need is some instructions.
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I haven't finished yet but I've started on an attempt to make a schematic. When I'm done I'll post it here so grahf can (maybe?) look it over and make advisements.
And while I'm posting can anyone recommend a resource that sells both the LM1881N and the ECS-2100AX @ 3.579545MHz (or a substitution for the LM1881N)? I'm trying to avoid ordering the former from jameco and the latter (plus the other misc. parts) from mouser.
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OK. Here is the first draft of what I would assume is the complete s-video conversion circuit. I think I screwed up on one part (see NOTE) and should have shown vertical sync (pin 3 of the LM1881) routing to pin 10 of the CXA1645M instead of composite sync (pin 1 of the LM1881). I left it as-is for now, though.
Can anyone confirm if this schematic appears to be laid out correctly? grahf?
Thanks.
NOTE: Like the diagram says, I don't know if this is laid out correctly, DO NOT attempt to build this circuit as-is.
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Kspiff, first of all welcome to the forum! Secondly, good job on the schematic. You saved me the trouble of finishing mine. As far as I can tell, everything is 100% correct. You did fine on the LM1881 also, the CXA1645 likes the composite sync input fine. The actual construction of this encoder isnt really hard, but its difficult to understand what goes where if your not familiar with electronics schematics and terminology. Plus, soldering to the SMD cxa1645s is a bitch. You really only need a few things:
cxa1645
Assorted ceramic caps.
Assorted electrolytic caps.
Assorted resistors.
The 3.579~ oscillator (makes the output of the chip NTSC).
LM1881 sync seperator (because the cxa1645 doesnt like the sync output from the HU6260 chip, so we strip a clean signal off of the composite video).
I made up a little elementry level chart for those who are unsure what the symbols on the schematic mean:
(http://files.myopera.com/grahf/albums/136150/components.jpg)
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Awesome. I may have to try to get this built today then since I've nothing better to do (assuming the good electronics store downtown has LM1881s and proper crystals). Once I test the build I'll take the "draft" markings off the schematic and maybe do a nice write-up in an HTML doc to send to gamesx.com. Is there anyone else who needs to be credited besides you? Did D-Lite help you, or anyone else?
I do have another question, though. I was thinking I might get a real Duo soon (there is a sweet package on eBay ending soon I might splurge on) to replace my Turbo Grafx unit, at which point I'll order another CXA1645M so I can mod both... but before I order just 1 more chip would this mod work with other systems with the appropriate inputs available? This seems to be a general purpose circuit and I was thinking it might be pretty sweet to put one of these in the ol' NES2, SNES mini, or Genesis1/CD/32X stack (well maybe not the latter since I'd probably have to mod all 3 units). If so I'm also guessing I might not even need the LM1881 for some other systems...?
And thanks for the welcome, not sure if I'll end up being a big poster here but it's good to see an active board dedicated to the Turbo and its various incarnations.
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No, nobody helped me at all. Most of my questions were answered by scouring over the GameSX board. Man that place is an invaluable resource. I owe a lot to that board.
This is a REALLY versatile chip, and yes, you may not need the sync seperator for other systems. Most of the FC Twins (snes clone + nes-on-a-chip) uses this chip stock, as well as playstions, saturns, and a number of other things. The genesis stuff usually has the older cxa1145 (which isnt so hot at svideo).
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That's awesome man, great job. I'm going to build the RGB amp for mine but I think I'll add S-video also just for the hell of it after seeing your schematic, it looks like it would be fun to build.
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GUTS, dont bother with the RGB amp if you plan on building this circuit. You can just tap RGB directly off the output of the cxa1645. It works great as a signal clamp, and from my understanding it will boost a weak signal as well. Try that first.
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Awesome guys. This will be another project that I can try to tackle in the future.
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at that point, i would say you guys a big thanks for your big effort. it seems, that i struggled only with the external oscilators on pin 10 and pin 6. but now i can go ahead and bright up my picture to an acceptable quality, since i know it will work according grahfs researches :mrgreen:
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Hey Keranu. This is a perfect thread to move to the new Turbo Mod section. :)
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Man, what a difference the picture makes. Its not perfect, but dot crawl is pretty much completely eliminated for me. You can tell immediatly in games such as Fray, where the textures in some of the towns turn into a disgusting mess with composite. Nice and stable with the svideo.
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Man, what a difference the picture makes. Its not perfect, but dot crawl is pretty much completely eliminated for me. You can tell immediatly in games such as Fray, where the textures in some of the towns turn into a disgusting mess with composite. Nice and stable with the svideo.
With S-Video on your Duo do see any faint vertical lines kinda like this?
(http://www.superpcenginegrafx.com/img/pce_svideo_lines.html)
The above image is an exaggeration, but I have a very faint version of those lines with my system.
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No, none whatsoever.
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Oh well... maybe I'll get another PCE modded in the future or see if someone can fix the one I have. :(
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Argh. Another day without Turbo s-video goodness. I accidentally picked up 0.001uF caps instead of 0.01. #-o I ordered some from mouser, but am hoping Fry's Electronics will have some when I stop by there this evening so I can be playing by this weekend.
I did however finish adding composite/RCA jacks (figured I may as well do both since s-video isn't very common), removing the RF hardware and putting the s-video jack in its place (which looks very nice and fits perfectly as long as you mount it upside-down -- otherwise the cable won't fit in properly because of the shape of the hole), and organizing the layout of the project board. Would be nice to have something to cover the hole where the channel selector was but I can live with the one little imperfection.
Too bad I can't find a 8PDT switch to do a region mod though (other than a push on/off type that requires 2 5/8"+ clearance behind it, which I don't quite have). And I was going to do an LED mod (thought it would look cool to have a blue LED shining from behind the Hu slot) but I'm starting to wonder if it would shine through the Hu slot gap enough to justify bothering with it. :-k
Oh, and does anybody know if I need to reattach the shielding to the PCB if I removed the RF unit? Isn't RF interference the primary reason for the shielding? I probably will put it back on anyways but if I can leave it off it would probably be easier to fit the project board in and reassemble everything. Plus I pryed off several of the grounding pads and would have to use flux paste to attach the shielding to some new grounding points (which I'm not looking forward to :().
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If it was my personal machine, I wouldnt bother with the shielding. The Duo-R doesnt have any shielding. (except on the bottom, but the top of the board with all the ICs is exposed. You can always do it later if for some strange reason you get interference, but its not likely.
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OK, thanks. I think I'll just put the bottom shielding back on then. There is a transistor which appears to be grounded through the shielding and I think it's screwed to the bottom half.
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Darn. I tested my build a little while ago and it didn't work. I'll have to go back in and double check everything I guess. Seems odd since I was very careful and triple checked everything (wiring, continuity, etc.) before I installed. Ah, well. I just hope I really got the schematic right.
I wonder if it has something to do with grounding all the components to the PCB w/ one wire, or maybe 0.30 gauge kynar wire isn't thick enough for connecting the CXA1645 (I didn't use kynar for the grounds or input voltage to the CXA1645 or any of the other components though)? Maybe I should have routed 2 separate grounds for the s-video plug instead of piggybacking them? Hmm...
LOL it was fun ripping into the PCB and top shield with a dremel tool though (as it turns out I needed the carve out the spot where the RF unit was to get the s-video socket to fit with the case closed).
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Your wire should be ok, these chips dont draw that much. You can piggyback the svideo plugs no problem, its how mine (and everyone else) is done.
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Hey guys,
for anyone who's building the S-video mod circuit, I just noticed something:
The schematic says that Pin 15 from the 1645 is Y-Out, and Pin 16 is C-out, but the data sheet for the CXA1645 has it the other way around.
What's the reason for this? When I first looked at the schematic I noticed something looked a bit strange, but I thought I just had to "flip it" because I was working behind the S-video jack.
Has anyone built the converter exactly as it is printed and had success?
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Hey kid_rondeau, good eye. I noticed on page 1 of the cxa1645 datasheet has it listed one way, but in the application circuits its listed opposite. kspiff, maybe this is your problem?
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Oh man! Going over the data sheets in FURTHER detail, I see exactly what Grahf was talking about! Yeah man, I would be inclined to think that it's a typo in the application circuitry rather than on pages 1 and 4.
Grahf, I saw your pics you just posted of your successful mod, and just by looking it appears that you hooked it up with pin 15 as C-out and 16 as Y-out. Am I correct? It would be nice to set the record straight.
And while I have you here...
Am I going to need the "Sync" line for this circuit? Following the GameSX pinout diagram, I have seven leads hanging out of my TG-CD:
GND
+5V
Sync.
Red
Green
Blue
Composite Video
Following the S-Video schematic, I see no need for the Sync...is that for component video?
Thanks!
-Mike
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I'm at work so I cant verify, but i'm 99% sure the first few pages of the datasheet are the correct ones, as this is the same pinout as the CXA2075 (which is a drop in replacement).
Yes you DO need sync signal (pin 10), but no, you wont be using the sync signal from the HU6260. The CXAs will take the weaker PC Engine RGB signals just fine, but people have reported trouble with the sync. Rather than building an amp, its easier to just use the LM1881 ic to strip a nice stable sync signal out of the composite video. Thats whats going on in the schematic.
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Ah, good eye. I did make a typo. Hmmm... I've got some time to kill this morning and if that works it would be an easy fix, I think I'll try right now and see if that was the problem.
EDIT: Nope. That wasn't the only problem apparently.
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I gotta tell ya,
I've been having a really fun time with this S-Video mod project. I majored in Electronics Tech at my college, but I always felt like I only had a textbook knowledge of the material, and was helpless when it came to circuit design.
But lately, I seem to be having a renaissance in all things electronic! And the camaraderie of these forums has only bolstered my resolve!
So, here's a quick update. After browsing data sheets for composite sync strippers, I've found that IC# EL1881CN is directly substitutable for the LM1881N, which I've had a difficult time locating from anyplace that doesn't have a minimum purchase. The EL1881CN is $1.94 from Mouser, and it's in stock.
My next task is to either find a good, close supplier for the Sony CXA1645/2075's, or else find a substitute for those.
When I get my TG-CD mod all finished and working, I'll post some pics!
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Electronics are awesome :) Mouser is great for buying singles of things. Not the cheapest though, but you dont always need an entire strip or roll of something.
Kspiff, if you cant get your board figured out i'll be happy to take a look at it for you. Send me a PM if you get frustrated with it. You've got all the right parts, so its probably something simple thats being overlooked.
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Oh, also, is it OK to use 1/8th Watt resistors throughout? I figured where space is an issue it makes sense. Also I assume 5WVDC is OK for all caps?
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1/8th watt resistors will be fine. About the caps, small are ok for everything except for the VCC1 and VCC2 decoupling caps. I use 10v caps on these lines just for overkill, and because they're more common. If you look at a factory board like a Playstation that uses this chip from the factory, most of the supporting caps/resistors are bare minimum (besides the fact that they are inherintly smaller due to being smd).
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I wonder if an AD742 would sub for the CXA chips? Of course all of the ones I have come across are the surface mounts. Oh well, save a mod set up for me Grahf heh. I will let you know when it is time. :dance:
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The AD724/AD725s do not work with the PCE for some reason. They also dont produce quite as good of a picture. The CXAs really are the best choice for this system.
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Grahf,
I finally finished my S-video mod for my TG-CD, and it works...just not very well. The picture (color, clarity) is beautiful, but it's kind of wavy and jumpy. Any idea what this could be? I built the circuit per the diagram, and the only substitution I made was using the EL1881C for the LN1881 which I can't find.
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I havn't tried the EL1881Cs yet personally, so unfortunatly I cant say. Its supposed to be a drop in replacement, so it SHOULD work fine.
Its hard to guess exactly what the problem is without seeing it in person.. It sounds like it could just be some interference. Double check the grounds, and also recheck the decoupling caps for VCC1 and 2 (make sure the polarity is correct on the electrolytic caps). Also, where are you getting your 5v from? If you look at the pic of my first board I posted on the first page, you can see that I pulled power from the middle of the board. There is a nice wide 5v plane which you can tap into.
Dont give up on it, you'll get it going eventually.
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Whoa, thanks for the quick reply!
Here's an update:
I rechecked my connections and saw nothing flagrantly wrong, so just for the heck of it I tried the sync line on the expansion board in place of the stripped sync signal from the composite...YUCK!! It was dim and B/W and the vertical hold was off...I figured I'd have better luck if I went back to how I had it before, and retried.
I don't know what I did differently...maybe I just had a crappy connection from the 1881 before, but...
WOW!!!!
What an INCREDIBLE picture!! The first game I tried was Sidearms. No more weird "flashy" buildings in the first part of stage 1! And all the blues look so rich!
It is ALMOST completely stable as far as the picture is concerned. If you look VERY carefully, there is some periodic distortion about a third of the way up every few seconds. It's so minor, though, that I scarcely even notice...and I'm VERY picky about stuff like that.
Thanks for the encouragement!
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If you look VERY carefully, there is some periodic distortion about a third of the way up every few seconds.
Those are my Dark Lord powers affecting the planet's magnetic field. Don't worry about it.
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The LM1881 is readily available in any quantity from Jameco if anyone needs them. Both SOIC ($2.34 each) and DIP ($2.85 each).
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OK! Got it!
I wasn't satisfied with the distortion on the picture (however minute) so I did some circuit cleanup last night, including:
-I didn't bus all the ground connections together
-I brought the 1881 about 1cm closer to the 1645
-I didn't use a socket for the 1881 (not sure if this helped, but you never know)
After about three hours of work, I tested it, and it works completely perfect now. Huzzah!
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Nice work man, congrats on the finished board. Its a great feeling when you finally get something working.
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Anyone know where I can get a cxa1645m? I see I can get the LM1881 from Jameco.
I don't want to order a bulk quantity of the CXA's, just 1 or 2.
So I guess if any member here has a couple extra they want to sell me... :-"
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If yo don't have a local source check ebay. They get sold off and on there.
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There's one listing up right now. The seller has 135 of these chips, but he's asking $20 a pop plus $8 shipping. Needless to say, shipping something the size of a quarter domestically doesn't even come close to $8. Beyond the obvious raping on the shipping charge, $20 seems a bit high to me.
Or is this what I should be expecting to pay for this item?
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Currently,yea,unless you have a local supplier that will let you pay slightly more then what they get them at in bulk.
You can also strip the chip off of dead Saturns and I think Ps 1 systems use them also.
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There's one listing up right now. The seller has 135 of these chips, but he's asking $20 a pop plus $8 shipping. Needless to say, shipping something the size of a quarter domestically doesn't even come close to $8. Beyond the obvious raping on the shipping charge, $20 seems a bit high to me.
Or is this what I should be expecting to pay for this item?
That's about the going rate. Unless you feel like buying 100 of them :)
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I bought everything else that I need to do this mod today.
I guess I'll go ahead and order a couple of those from that eBay seller.
I'm going to go ahead and build an encoder based on grahf's work early in the thread. I'm going to do the mod first on a core TG-16 and see how it goes. I might try my Duo next if all goes well.
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Odd place for my first post, but -
I just bought into the TG16 world for the first time this week. The original U.S. TG16 should arrive any day now. It's pretty exciting. I have never owned a TG16 OR played a TG16. I remember the commercials for it - going to Babbage's and seeing it out on display. Never played it.
That day will come to an end soon as it gets added to the collection of game consoles and games. One thing I make a hobby is improving video output of VG consoles. I'm not a guru in the area at all - I just have an interest in it.
nat - I would like to hear about your experience modding the core TG-16. I have an external RGB -> S-Video solution for the Sega Genesis, and I wouldn't mind rigging up a cable on the TG-16 that allows it to use the Genesis adapter. I am not sure if the level of RGB output is the same for the TG16 compared to the Genesis or not. If so, it should be an easy mod.
Look forward to talking TG video output with you guys,
CK
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I haven't done much with regards to video on the Genesis, but I can tell you that if you're looking to do an external "mod" on the TG-16, there is an expansion port on the back where you can tap the video signal directly off the VDC. You can get both RGB and composite from this port. I am assuming you are tapping the RGB signal from the Genesis in a similar manner, so your method would probably work on the TG-16 too.
The mod that I am doing is internal-- I'm actually going to add an S-Video port to the machine itself. Ideally, I'd like to do a component video mod but I understand that would be a bit more difficult.
Anyway, here is the pinout for the rear expansion port:
AR GG 01 VM 32 30 27 GG 17 20 22 23 13 11 10 08 GG 05 03 GG VV VN VR
02 CD 35 34 VU 29 26 15 19 21 VJ 14 12 VG 09 07 06 04 24 VT 37 36 VP
AL VV VS 33 31 28 25 16 VL VK QQ VI VH QQ VF VE VD VC VB VA GG VZ VQ
The pins you'd be interested in are:
VR -- Blue RGB signal
VP -- Green RGB signal
VQ -- Red RGB signal
VN -- Horizontal sync signal
VZ -- Vertical sync/composite video feed
AR -- Audio Right
AL -- Audio Left
All "GG" pins are ground.
I've personally never done anything with an RGB signal from one of these machines, but I have rigged up a few connectors over the years so I could use standard A/V cables for stereo sound and composite video on a core system that only has RF out of the box. Since I absolutely refuse to touch RF.
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And BTW, forum member D-Lite does TurboGrafx mods as a hobby. If you wanted to get your system "professionally" modded, he's the guy for the job.
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I've actually talked via e-mail once before with D-Lite. I had some bad luck with the CXA1145 chip in my Model1 Genesis...
Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.
Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.
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Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.
I think you can get the same result using just the VZ pin for sync and forgetting about VN, in that case. I'm sure D-Lite will correct me if I'm wrong but just VZ should be sufficient.
Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.
Unfortunately, no. Not of any standard I've ever seen, anyway. I have extensive background in computer electronics and it's not used on anything else I've ever dealt with. As far as I know it's a proprietary connector.
The easiest way to tap signals off individual pins is to use an old SCSI/IDE ribbon cable and slice up the connector to effectively create single pin headers with a decent length wire attached. It's extremely easy to separate the wires on a ribbon cable. This is how I created my "custom" connectors.
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I've actually talked via e-mail once before with D-Lite. I had some bad luck with the CXA1145 chip in my Model1 Genesis...
Hmmm....the Genesis uses a single composite sync that carries the combined Horizontal and Vertical Sync information rather than the separate sync info like the TG supplies. I assume these can be combined by tying them together - possibly with some resistors in the mix. Not certain.
Is that expansion connector a "standard connector" of any one type by chance? I don't have the TG16 yet. I look forward to getting it and investigating mod possibilities. That's quite a bit of useful signals on that expansion connector.
Nothing standard about the expansion port connector unfortunately. Your best bet is to get a cheap Tennokoe Bank 2 or AV Booster and pirate the connector out of that.
For the sync signal to input into the CXA chips, I've had much better results stripping sync from the composite video than tapping pin #44. Seems to come through stronger.
Hope I was able to answer whatever questions you had with the Genny stuff back then. If not shoot me another e-mail
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Hey D-Lite, thanks for your input. Looks like pcenginefx has a really great community here.
So did you use an LM1881 to pull out your c-sync? Seems like it is a useful chip to have around.
Do you know what "state" the TG16 RGB circuit is in at the point it reaches the expansion connector? I know that all these video game consoles liked to put some components in the SCART cables rather than have each RGB output be ready to plug. The Genesis output needs a 75 ohm resister and 220 uf cap before it hits "standard" RGB output. My external converter most likely expects the signal to be "pre 75 / 220" as it plugs directly into the Genesis DIN port, so my experiment requires I essentially match the native RGB output of a Genesis in order to use the adapter.
Any thoughts?
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The Turbo's native RGB output straight off the expansion port should be roughly equivalent to that of the Genesis.
Check out this page for some more info about pulling RGB off the expansion port:
http://www.gamesx.com/rgbadd/duorgb.php
I see it mentions an amp near the end of the article that uses a 75 ohm resistor/220uf capacitor combo. You'd undoubtedly be just fine using the same setup you've got for the Genesis provided you can construct some kind of connector.
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Oh awesome. Things are looking good so far...
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Hey folks. I finally found a "cheap" source of CXA1645 chips. I bought a couple of broken PS1 consoles off ebay and am in the process of stripping the chips out of them. Works out to be about $10 per chip.
Unfortunately, the first one is not going into the duo. I'll let you folks know how it works using the RGB out from the Genesis.
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Hey folks. I finally found a "cheap" source of CXA1645 chips. I bought a couple of broken PS1 consoles off ebay and am in the process of stripping the chips out of them. Works out to be about $10 per chip.
Unfortunately, the first one is not going into the duo. I'll let you folks know how it works using the RGB out from the Genesis.
Saturns too. Actually, I think the Saturn has the 2075. And the Genesis model 3 has the 1645 in it.
Passing the RGB through those chips is also a nice RGB amplifier for the Turbo systems.
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Both my Saturn first gen decks have the 1645 in them.
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are there any news or changes concerning the draft-schematic kspiff once did? would be great if this could be confirmed as 100% working :)
thanx a lot :)
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are there any news or changes concerning the draft-schematic kspiff once did? would be great if this could be confirmed as 100% working :)
thanx a lot :)
Tatsujin,
I have built and can confirm the functionality of kspiff's schematic WITH THE EXCEPTION of pins 15 and 16 on the 1645...
On his schematic, he has pin 15 going to Y-out, and pin 16 going to C-out. But the circuit should be wired OPPOSITELY. (Although, interestingly, the pin numbers listed are correct, e.g.: Pin 15 does go to Pin 4 of the S-video socket, and Pin 16 does go to pin 3 of the S-video socket. They're just labeled backwards.)
In other words:
Pin 15 from the 1645 must go to C-out, and pin 16 must go to Y-out.
It's not his fault that he listed it incorrectly; Sony's product data sheet contradicts itself.
The only other difference between the way he listed it and the way I built it is the substitution of an EC1881 for the LM1881N, which is a direct drop-in replacement.
Other than that, I built it 100% true to the diagram, and I can confirm that it works.
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thanx a lot kid^^
shame on sony and its unproper documentation :lol:
as soon as i got the parts, i will start with it.
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Has anyone thought about designing a board for this and getting it printed? It would certainly help keep things neat and tidy when putting the board together.
It may also be helpful to have a "video game S-Video" FAQ as it seems there are plenty of systems you can use that 1645 with. I don't know if there is a FAQ out there yet or not. ....maybe I'll write one. I would be very tempted to fill it full of anti-1145 propaganda, though. I can't stand that chip....
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Same here,I also cant stand the AD724,the favored chip of the Neobitz,useless piece of shit of the encoder world.
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Alright. That's it. I'm writing an S-Video mod FAQ for multiple consoles - starting with the Turbo/PC-Engine. It's about time one gets made. I've been running around newsgroups, google, neogeo.com, atariage, benheck, and now pcenginefx too much.
If someone knows of one that has already been made, please let me know and I'll save myself some time.
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No one has written a FAQ for the Turbo.
That would be great for all the DIYers out there. Can't wait!
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Those of you that ordered from Mouser or Digi-key or wherever, would you mind posting your part numbers that you used when ordering? If you have the e-mail or invoice filed away somewhere, do you mind dusting it off.
I am going to try to put together that S-Video FAQ and it might get paired with a how-to depending on how ambitious I am. Since I am going to gear this toward Turbo consoles, I might as well take the time to modify mine as I write the guide.
After I get a good idea of part numbers, I will probably order those exact numbers and then use them in the FAQ to make it easier on those that need a grocery list.
I personally started filling up a cart on digi-key...but I don't know if that is the route I want to go or not.
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If someone could put up a copy of the trace for the little project board part, then people could just print the PCB themselves and just insert the parts in the appropriate holes:
http://www.5bears.com/pcb.htm
Well, if they had a laser printer, but maybe you could do it at Kinko's or something.
:-"
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Any updates on the guide? That would be awesome if you could put that together!
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bump - BTW I ordered a board that is designed to make soldering to SMT pins easier. Will see if this will work with the CXA1645 chip from a Sony PSX.
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Hey Duo_R -
No updates on the guide. I collected a lot of information, got sidetracked in messing with SCART/Component video options for various consoles...and then had Hurricane Ike hit. ....someday...
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just a correction to the diagram that was previously made by Kspiff. Corrections to the Y and C pins.
(http://img27.imageshack.us/img27/8206/indexfixed.th.html) (http://imageshack.us/photo/my-images/27/indexfixed.jpg/)
Kspiff, first of all welcome to the forum! Secondly, good job on the schematic. You saved me the trouble of finishing mine. As far as I can tell, everything is 100% correct. You did fine on the LM1881 also, the CXA1645 likes the composite sync input fine. The actual construction of this encoder isnt really hard, but its difficult to understand what goes where if your not familiar with electronics schematics and terminology. Plus, soldering to the SMD cxa1645s is a bitch. You really only need a few things:
cxa1645
Assorted ceramic caps.
Assorted electrolytic caps.
Assorted resistors.
The 3.579~ oscillator (makes the output of the chip NTSC).
LM1881 sync seperator (because the cxa1645 doesnt like the sync output from the HU6260 chip, so we strip a clean signal off of the composite video).
I made up a little elementry level chart for those who are unsure what the symbols on the schematic mean:
(http://files.myopera.com/grahf/albums/136150/components.jpg)
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I just finished performing this mod for myself. Congrats to everyone who worked on this project!
Before trying the mod on a Duo (was kind of afraid I might damage the Duo if I did something wrong), I tried it on a US TG16. Built the circuit and tried it out. The result was a sharper picture but with a lot of bleeding and color distortion. Double checked everything on the CXA board and everything seemed fine. I then decided to build a second CXA encoder pbc. Obtained the same bleeding and distortion. Double checked everything once again and everything seemed fine. Thought the problem might be on the TG16 itself so after a dozen hours of work, I connected the encoder to my Duo and powered it up. IT WORKED JUST FINE! Hurray!!!
S-video vs composite on the PCE doesn't make a difference as huge as I expected (not as much a the Genesis s-video vs compsite anyway) but it still is really great to have a sharper, less washed out picture on screen. I've been looking for a PCE s-video mod like this for years!
Anyone else had problem with this mod on a Turbografx system or is there really some problem with the system I have? I'll eventually be able to try the encoder on another Turbografx to see if the problem comes from my system or not.
With S-Video on your Duo do see any faint vertical lines kinda like this?
(http://www.superpcenginegrafx.com/img/pce_svideo_lines.html)
The above image is an exaggeration, but I have a very faint version of those lines with my system.
I actually have these faint lines which I noticed for the first time on a white screen. Unless a white screen shows up, I can barely see them.
I have also noticed that in the Kaze Kiri option menu, the blue background is kind of wavy (not the text but only the blue screen). There is some slight pixel movement in the blue color when compared to the composite output. Maybe this is normal thought... I'll perform more tests soon.
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The faint lines on white backgrounds and the wavyness/RF like interference on solid blue backgrounds is always going to happen with PCE/Duo S-video mods. The RGB coming from the GPU just comes out that way. Mostly you just get rid of the shimmering, rainbowing and dot crawl with the mod. It is still worth it in every way. I also noticed that if you use a shorter S-video cable, it comes in a little stronger and there is no dot crawl at all on the blue backgrounds you mention. Avoid S-video selector boxes if you can.
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i took a gander at this mod following the revised schematic to the T. worked great and thanks kspiff,graf,duor,nat and everyone else for all the helpful info.
Making the pcb was quick and easy,just a few hours but what took a heck of alot of time was locating and ordering the parts. between digikey,maouser and ebay months had passed. this is what i made for a client(named withheld for anonymity)
i was gonna make 3 test boards each with different chips and components bought from multiple sources so the chance of failure would be slim but time was running out so made 2.
board 1:
http://img.photobucket.com/albums/v238/jetbue7/chiptopus.jpg (http://pic.photobucket.com/bwe.png)
http://img.photobucket.com/albums/v238/jetbue7/board1finished.jpg (http://pic.photobucket.com/bwe.png)
http://img.photobucket.com/albums/v238/jetbue7/board1back-1.jpg (http://pic.photobucket.com/bwe.png)
chip harvested from a dead ps1,cxa1645 chip surface mount. snowkitty helped in the harvest.
the chip was wired to make it easy to handle. Both boards were done with common telephone wire braided and solid core chosen for its durability.
board 2:
http://img.photobucket.com/albums/v238/jetbue7/board2finished.jpg (http://pic.photobucket.com/bwe.png)
http://img.photobucket.com/albums/v238/jetbue7/board2back.jpg (http://pic.photobucket.com/bwe.png)
done with a DIP cxa1645 chip,larger for easy soldering.
this was a prototype so i can just drop in a chip of my choice and solder. pre wired board but was to big so it was scrapped.
http://img.photobucket.com/albums/v238/jetbue7/protoboard1.jpg (http://pic.photobucket.com/bwe.png)
http://img.photobucket.com/albums/v238/jetbue7/protoboard1back.jpg (http://pic.photobucket.com/bwe.png)
i had to use my own breadboard cause the one suggested was way to small for me to use. to make more wire and connections i drilled some of the breadboard holes larger.
The boards were sent untested to my client cause they were meant for a duor or rx. i didnt want to test them on my american duo cause the chips are on the bottom and will be difficult. So i prayed to the various gods and goddesses that at least 1 will work.
client plugged in board 2 first and it didnt work. found out from my pics i soldered on some wrong pins ](*,)
he fixed the wrong pins but still a mess of a picture. I figured cause of my mistake the chip fried as soon as it was plugged in. mmm fried chips =P~
client plugged in the first board and it worked great after some ground tweaking.
So i can be witness that the schematic here works great and the mod. will be making a few more boards and do more testing. hopefully smaller boards than the monstrous ones i made :)
a rough drawing of the layout used for them:
http://img.photobucket.com/albums/v238/jetbue7/layout.jpg (http://pic.photobucket.com/bwe.png)
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Glad to see so much success with this mod. I think I might try this out with my TGCD unit next time I'm bored :) Thanks for all your work guys!
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How important is the 0.1uf capacitor connected to pin 13 on CXA1645M before it goes to ground? What is it even for? I didn't have one on hand, so I built my latest encoder with 1uf in its place because it was the closest I had... I know you shouldn't do that, but I can't figure out what this particular capacitor is even used for. It doesn't seem very important IMO. However, the joke's on me because the encoder outputs no video. I find it hard to believe substituting a 1uf in place of that 0.1uf would be the cause, but I thought I'd check to be sure.
If that's not the cause, as I suspect, I've got something else going on. Which is a real bummer because everything looks good and I've triple checked all my connections. I'm trying to mod an RAU-30, which I've never done before, to avoid cutting into my SuperGrafx.