PCEngineFans.com - The PC Engine and TurboGrafx-16 Community Forum
NEC TG-16/TE/TurboDuo => TG-16/TE/TurboDuo Sales & Trades => Topic started by: incrediblehark on December 30, 2011, 04:00:50 AM
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I just recently got a turbo duo, and had it region and rgb modded. everything works great, but for the rgb I'm getting the noticeable jailbars and some faint interference on the screen. I know there are some rgb amps that have been made that will essentially eliminate any of this for a near perfect picture. If anyone can provide this service or can build the amp please let me know! :)
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Unfortunately as of yet I have not found anyway of eliminating the jailbars/lines. I have been researching many forums and no one has been able to solve this. I tried 3 different mods and they all produce these lines to varying degrees. All of these mods use the composite video to sync which if you look closely produces these lines as well. Maybe cleaning up composite or finding a way to use c-sync off the chip would help. The only suggestion I can make is to check all the grounds for the mod and the cable. If the ground is not solid it will intensify this issue and add interference.
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Sorry if this is slightly off topic, but are you saying that all RGB mods for DUO systems produce lines and interference? Can you post an example of what this looks like? Because I'm considering doing a mod to improve the video output of my DUO but might give up the RGB mod if it's inherently flawed...
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I dont recall having jailbar issues on the RGB modded systems I've used.... Most of them used composite for sync also. They were typically based on the NJM2267 amp I believe.
Someday I'll get around to having these amps built...
only 1 1/2" square:
(http://i905.photobucket.com/albums/ac253/bmcdanold/Repair/RGBAmp_SyncFinal2.jpg)
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All of the mods I have tried have this problem. The one that has it the least is the one that uses the NJM chip for the amp. I have to see if I can find a picture that shows this better. Most games this is barely noticeable except when a solid light color is present in the backround. Games that have this the worst are all of Shinobi, all areas in China Warrior, alt level 2 in Dracula X, konami logo, some of the cutscenes in Y's, and some of the cutscenes in Double Dragon 2. The composite video has this issue too if you turn up the brightness you can kind of see it.
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my sega rgb mod has no jail bars, using a sony CXA encoder as the amp
im running sync on green not composite as sync
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I have one of these amps:
http://www.ultimarc.com/vidamp.html
Would that work out good for TG16 rgb mod as an amp?
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thats an odd amp, as i havent heard of a display wanting over 1V of Vid
that amp converts vga to cab display
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its an arcade monitor amp.. bought it for my mame arcade machine but never used it since i ditched my arcade monitor and went for a LCD. Arcade monitor is just RGB seperately and sync. Seems like itd work right?
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yes it should work, it just may need 3 resistors added
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I'll try to post up some pics soon, I have two rgb pce/turbo systems, a us turbo duo with the jailbars, and a pc engine hooked up to an ifu30 thats been rgb modded. this one is a lot less noticeable, i think its there but the picture is a lot brighter so I don't see the interference or jailbars, which im fine wth. but i want to use the duo.
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Hey Blue, would you mind sharing the resistor and capacitor values for that NJM2267 circuit? The original amp design is from here: http://baku.homeunix.net/RGB/PCE_DuoRX/PCE_DuoRX.html but it's not so clear to me exactly what values he's using. Plus he's using a transister based pre-amp/buffer, which some folks are leaving out. I already built one of the simplified versions of these amps, but the output was a bit weak. It sucks because all my equipment is still back in the US, so I can't really test the signals.
Here's the one I built:
(http://lh6.googleusercontent.com/-sPl47L8fJEw/Tv157j5-E5I/AAAAAAAAB1k/KElDcFP__y0/s600/DSC_0213.JPG)
I ended up replacing it with a simple transistor based amp for now. I just got one of those new XRGB-minis (the XRGB-3 replacement), which luckily likes the transistor amp just fine, but i'd like to finish the NJM amp eventually.
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I'll try to post up some pics soon, I have two rgb pce/turbo systems, a us turbo duo with the jailbars, and a pc engine hooked up to an ifu30 thats been rgb modded. this one is a lot less noticeable, i think its there but the picture is a lot brighter so I don't see the interference or jailbars, which im fine wth. but i want to use the duo.
You probably already looked into this, but the interference issues could be as simple as using a noisy power source. Adding a nice sized cap between power and ground might sort it out, or you might try changing to a different power source.
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where exactly do I add the capacitor? I tried adding some from the amp to ground and amp to power but didn't work for me. but maybe i was doing it wrong. the power supply is the official duo ac adapter, whats a suitable replacement? I have a radioshack one but it wont power this thing like it does the ifu.
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you want the amp to use the +5 from the internal regulator.
add a 1uf ceramic and a 480uf from the +5 to ground as close to the amp chip as possible
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Thanks for the info thesteve, I don't think I have any spare 1uF so I'll take a trip out to Radioshack and hopefully give it a shot today. :)
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So I tried adding the caps as suggested and still no change, although I could have just done it comepletely wrong. I tried taking pics but didn't come out well. I also tried a different power supply but no change. In all honesty its not that noticeable except for solid colors and when the screen is moving. I think if I can figure out how to make the picture brighter like the pc engine it might look the same. In the end I'll probably have to have someone else take a look at it.
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I have the same problem to, my rgb modded system also has jailbars. steve, did you add your own encoder to your duo, or can you get rid of the jailbars by switching the rgb mod to green sync, instead of composite sync?
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my duo isnt modded, as i didnt have an amp setup handy.
one of me genny2's is and its running sync on green for direct connection to my monitor.
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is it possible to resolder the internal wiring to put sync on green instead of composite? I would be a matter of changing just one wire would it not? the jailbars can be pretty noticable depending on the game.
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it would take a couple parts to bring the sync up to ttl level and then a diode and cap to integrate it
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And if that doesn't work out, you can also try using an LM1881 sync separator. They use a super simple circuit, and usually produce a rock solid, clean, sync signal.
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If its something I could easily solder to together then i could probably do it, otherwise I'm going to have to have someone look at the system for me.
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If you can solder at all, it's super easy. If you get stuck, just ask.
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Thanks for all of the help everyone :) So what would I need to do with a sync separator? is this something I would build?
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yes its something to build.
you would use it to give true sync instead of composite to your monitor.
the "less bright" condition bugs me a bit. what amp are you using (chip, transistor, numbers)?
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Just opened it up and took a look. I had this installed by someone else (my other, better picture rgb system I had the same person build the amp but i did the rest of the work myself) The 2 chips read as follows:
2267D
JRC
7028B
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NJM2267, the same amps I had planned on using on my amp chip. I've seen them used before with good success. According to steve's calculations, it should be good if the surrounding components are done properly.
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And my pc engine rgb amp is the same, but for some reason the picture is brighter / jailbars virtually nonexistant on the pc engine. :-k
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look at wire routing (especially before the amp)
you could be getting crosstalk from the composite wire.
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I'm wondering if the difference is that in the Duo the rgb is tapped directly from the HuC6260 as opposed to from the expansion port on the PC Engine.
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that could make a huge difference
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Do both systems have the 75 ohm resistor on output? Some modders may leave this out assuming you will put this in the scart/output cable.
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So I'm willing to accept that its the cause of tapping the HuC6260. I don't think there are any other points to get rgb from on the duo systems so I'm going to call it good. It still is a fantastic picture and hardly noticeable, I'm just very nit-picky I guess. Unless I try a sync separator as grahf mentioned (not sure how to build one) I'll stick with the PC Engine.
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without the resistor the pic will be too bright (if the chip needed one) but should not cause jailbars.
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solved
to solve jail-bar issue on rgb modded system replace capacitor C961 10uf with 100uf tant or 220uf aluminum.
the cap is from hu6260 pin43 to ground.
C142 on the TG16
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Wow! Thanks thesteve! I'll give it a shot later today, I didn't think this would ever really get resolved. I'll swap out that cap and post the results (hopefully) later.
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I have a question that's sort of similar to this and what I'm about to suggest may sound extraordinarily dumb but, I don't have enough experience with electronics to calculate the outcome so, I usually just experiment with stuff and see wait to see what happens which I know is also dumb and unsafe but, I sometimes lack the patience to buckle down and study so, I'd like to know from someone who has an intimate knowledge of video connections/mods to tell me if they think that this idea might work. I'll just post a pic so, you can see what I'm getting at.
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simple answer........no (what was the point?)
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simple answer........no (what was the point?)
Shoot! I sort of expected that. So, it wouldn't split the composite video into the three types of video needed to produce component video?
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nope
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If only it were that simple.... :) would save a lot of trouble :P
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So, mmm... What *would* happen? Would it wreck something if I tried it anyway?
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wouldnt hurt a thing
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wouldnt hurt a thing
Yeah? Well, that's great because I just loooooove to experiment!
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So I tried the cap swap and its very close, but not quite there yet. I attempted to take some pics and will upload them later
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ya could try adding a ceramic chip cap across the pins hu6260 pin43 to ground (pins 41 and 42) for additional filtering.
it was a major improvement right?
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It was only a marginal improvement, but still an improvement I believe. The jailbars are very close to being gone. Still gotta up the pics, hoping to get a chance tomorrow.
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Holy crap does this actually work? :pray:
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try it
im sure other caps failing would also cause picture noise, but that cap is just not big enough
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Ok, so here are pictures of the two systems. RGB Output is using the same cable, on the same display, a Sony PVM Monitor. Both were tested using PC Genjin 2.
Here is the PC Engine:
(http://pic.photobucket.com/bwe.png)
And this is the Turbo Duo:
(http://pic.photobucket.com/bwe.png)
As you can see there is hardly any difference, both systems have a great picture, but the Duo does have the more noticeable vertical lines. It probably sounds like I'm being extremely anal about this, its just that I would like to use the Duo as my everyday system but if the PC Engine has the better picture I'll just stick with that one.
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wow those are narrow lines.
my tests involved wider lines that were less distinct.
the pic looks a bit weak on the duo as well, that deserves investigation
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Thats what I meant when I was saying the picture was brighter on the pc engine. well the pics speak for themselves! :)
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i just did 2 RGB mods
1 my black duo
2 an IFU
screen shot (http://pcengine.freeforums.org/download/file.php?id=22)
the amp (http://pcengine.freeforums.org/download/file.php?id=27)
installed (http://pcengine.freeforums.org/download/file.php?id=26)
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Nice job Steve! Hopefully this is what Beemer does to mine. :)
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Very nice! that's a pretty small amp too. so you're not getting any of the lines like mine? for me its most noticeable on solid colored backgrounds like blue or green.
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i get a small amount on black and blue, but nothing close to as bad as yours.
take a volt meter and compare the dc voltages on the inputs to the amp.
if your voltages are lower on the duo it could mean a bad input cap on the amp.
PS you have the same duo as me
if you havent had a full cap change its highly recommended and does improve performance.
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Steve, that is outstanding picture quality on that. And i thought mine looked pretty good. I dont get any of the lines that incredibleshark has, but i do have some jailbars only when black is showing. those jailbars exist though all the time not matter what i'm doing. i think my lcd is just crap. Will putting that 220uf cap on that you mentioned help regardless of what rgb mod you have? I have 1 uf ceramic caps, you recommend putting them from pins 41,42, and 43 to ground?
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pins 41 and 42 are ground
so the cap from 42 to 43, and if you bridge 41 to 42 no prob
yes its an improvement to any (even composite)
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the ceramic caps i have are not polarized so i would solder one leg on 42 and one on 43 and i would be good to go eh? I know i'm just repeating what you just siad, but i'm being extra careful. you mention a 220uf cap on c961 as well. what exactly does that do?
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yes thats right
both caps reduce the noise on the videoprocessor
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pins 41 and 42 are ground
so the cap from 42 to 43, and if you bridge 41 to 42 no prob
yes its an improvement to any (even composite)
Is that on the HuC6260?
PS you have the same duo as me
if you havent had a full cap change its highly recommended and does improve performance.
I may have to go that route but would feel more comfortable having someone else do the cap replacement just because its a US Duo and I've had a bad luck with these systems in the past
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Ahh, if you haven't had caps, that may very well be your issue to begin with! :D
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yes thats the huc6260
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I'm gonna give this a try as soon as i get a bit that will open my duo. I heard i could make one by melting the end of a bic pen, but i dont have one of those either :)
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If you're just opening it the one time, order one of those cheap china security bits (as they're good for maybe one use anyways) and get some replacement screws. :D
Melting the end of a bic pen? seems unlikely that it'd work. The screws in Duos are usually tighter than darnit if they've never been out before.
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I saw the bic pen thing on another guys site. He claims it works, i dont know, i have never done it. My duo has been modded before so the screws might not be that bad. I tried to order the security bit, waited 3 weeks and they sent me the wrong one.
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The pen trick never worked for me, I'd just invest the money in a good gamebit.
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Steve, c961 in my unit has a 10uf 50v cap in it. I need to match the voltage do i not. My 220uf caps are only 25v.
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Steve, c961 in my unit has a 10uf 50v cap in it. I need to match the voltage do i not. My 220uf caps are only 25v.
Has that cap been replaced by someone? The only 50v cap I know of in the duo is the 1uf one by the cd drive connectors...
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yes it was recapped when i bought it. its a doujidance dou-r.
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it should be a 16V cap.
anything 16V or more is good.(6V would be fine for that cap)
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Ok everyone, I followed steve's instructions and installed a 1uf ceramic cap on pins 42 &43 of the huc6260 chip. Then I installed a 220uf cap on c961 that sits directly below were you put the ceramic cap. After installing the two caps the improvement on the composite video is the most dramatic for me. The improvement on the rgb video is still very noticeable. Thanks to all the advice from everyone in this thread, and special thanks to steve, my output is alot better. It was really good before. Dont ask for screens, as i have stated before my camera sucks. Lets just say that making the adjustments to your duo is worth it.
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C961 that sits directly below where you put the HU-Card
fixed it for ya
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LOL, yea thats what i meant to say. thanks.
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Still have to try caps on pins 42 and 43 good to hear it worked for you!
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1 cap between 42 and 43
the shorter the wires the better
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shorter wires the better.........grrrr. Now i gotta do the ceramic cap again. I left the wires long cause i was having a hard time holding the cap.
Edit: Ok, I scared the hell outta myself when i almost pulled a trace removing the ceramic cap. I fixed it, shortened the wires on the cap to about 3/8" and resoldered. so far so good.
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I can confirm that I too have jailbars with my RGB modded duo from DoujinDance on ebay. The colors and picture looks great but yeah you do notice the faint jailbars on lighter solid color screens.
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I still haven't tried the extra capping between 42 and 43, every time i open the system the region switch wires pull apart and it annoys me so I've been putting it off.
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Is the cap on pins 42/43 supposed to make my picture brighter? I have been messing around and got the picture way too bright, colors washed out, but no interference/jailbars. I tried to since recreate that or tone it down using a different cap but no luck. Looks like I may just need the full cap replacement next.
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it will make the pic slightly brighter, as it stabilizes the output stage of the chip.
odds are you bridged it to 5V as it should be slightly below 5V
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ok i thought i must have screwed something up when it was like that. yeah after i rechecked my soldering there wasn;t much change in picture.
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neither cap by themselves made a huge difference for me, but both of them made a noticable difference.
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Hi everyone.
I finally got round to starting an RGB mod on my PC Engine DUO, well actually I did a 5 Pin DIN to 8 Pin DIN swap a year or 2 ago - may be more (this mod has been in the works for 10 years I'm sure :oops:)
I made the RGB 8 Pin to Euro SCART yesterday,
And today wired the HU6260 to 3 RGB wires, and then wired the backside of the 8 Pin DIN Socket to 3 more RGB wires, the idea being the RGB amp goes in the middle of the 2 lots of wires.
Shielded cables used all the way - I only want to do this once, and do it right!
As soldering onto the HU chip took a while (i.e. bl***y difficult) - I left things at that.
Except I couldn't resist joining up the 2 internal sets of RGB wires that were meant to be the in / out from the yet to be made RGB amp (which will be NJM2267 based) :lol:
The picture was actually pretty good, not dark in any way, but I did notice jailbars on large areas of solid colour. I need to put a switch in my SCART so I can flip quickly from C-VIDEO and RGB to do a really good back to back comparison of colours, so I'll pass on that for now.
Now the NJM2267 RGB amp may well reduce the jailbar effect, but if there is anything else worth doing now, I'll give it a go. Like I said, I want to do this to the absolute best quality I can, even if the improvements are minimal.
From what I understand, its possible to stick a Capacitor across the power input of the HU chip, to smooth out its power feed?
I think this is what is being suggested here http://baku.homeunix.net/RGB/PCE_DuoRX/PCE_DuoRX.html#add-passcon - any Japanese speakers please translate!
Also - someone suggested a CAP mod in this thread too.
Could anyone (preferably someone who has actually done it) let me know what CAPs I need, and between where?
Any other worthwhile tweeks, please let me know.
thanks!
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just from the pic's in the jap thread, i can tell you this thread is the english equiv.
the pins are the same.
the shorter the leads the better. (ceramic chip across the pins of the chip is ideal)
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just from the pic's in the jap thread, i can tell you this thread is the english equiv.
the pins are the same.
the shorter the leads the better. (ceramic chip across the pins of the chip is ideal)
OK - so what CAP across what Pins?
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i have some 22uf size 1206 SMD ceramic caps that work great.
you could get away with about anything (preferably ceramic or tantalum)
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i have some 22uf size 1206 SMD ceramic caps that work great.
you could get away with about anything (preferably ceramic or tantalum)
Sorry if I'm being dumb - but across what should the CAPs be placed?
This thread mentions HU6260 PINs 41 and 42 as ground, but here it says they are +5Volts:
http://gamesx.com/wiki/doku.php?id=schematics:hu6260_netlist
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now i will have to look again. (5V it is) doesnt matter with ceramics
pin43 is the one you care about.
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solved
to solve jail-bar issue on rgb modded system replace capacitor C961 10uf with 100uf tant or 220uf aluminum.
the cap is from hu6260 pin43 to ground.
C142 on the TG16
Just swapped the C961 10uf SMD cap for a 100 uf SMD cap. Jailbars I was seeing on PC Genjin 2 in the blue areas of the sky have gone.
Thanks Steve!
I would recommend everyone to try this first, as it's so easy to swap.
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Another quick question - where is the best place to tap 5 volts to power my NJM based amp? I'm going to stick the amp PCB over the HU card slot, as there is plenty of space there, and no heat sources.
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Another quick question - where is the best place to tap 5 volts to power my NJM based amp? I'm going to stick the amp PCB over the HU card slot, as there is plenty of space there, and no heat sources.
Since you'll be sticking it over the HuCard slot, pin 38 on the slot would be an ideal place to grab 5V.
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Ravij you were using the same test game as me :) I still need to get back in my Duo and see if I can finish cleaning up the picture, maybe tomorrow
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I've done the RGB mod on two TG-16 (US models), a Core II, a Super Grafx and last week on a PCEngine DUO. Ι used the same amp on all of them (made them myself according to the schemtics of the good amplifier http://www.pcenginefx.com/forums/index.php?topic=9299.0) and all capacitors were replaced with fresh ones on all of them (total recap). I also own a DUO-R that was bought already modded for RGB.
The DUO has by far the worst jailbars problem of all...
I noticed that if I use the non amplified sync signal tapped from the chip instead of amplifying it too, the bars are less obvious (i'm reffering to the DUO only)... I'm using bikuriman world as a test cartridge, the bars are very obvious on the blue sky at the begining of the game.
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solved
to solve jail-bar issue on rgb modded system replace capacitor C961 10uf with 100uf tant or 220uf aluminum.
the cap is from hu6260 pin43 to ground.
C142 on the TG16
When you say "220uf aluminum" do you mean electrolytic 220uF capacitor?
What voltage should someone get for the 100uF tantalum capacitor?
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you should be able to use a 16v, but I don't think higher voltages make a difference if you can only find ones rated higher
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i used 100uf 16V tant
the circuit is about 4V
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Do the tantalum caps have polarity like the electrolytic ones? From pictures on google i see they have a stripe, probably the positive pole?
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correct the stripe is positive on tantalum.
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Will these suffice? http://www.ebay.co.uk/itm/100UF-16V-SURFACE-MOUNT-TANTALUM-CAPACITORS-x10-blb173-/400267121772?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d31c7946c
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thats what i use
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Thank you... I went to a local store but they only had the non electrolytic tantalum type (without polarity) so I'll get some from ebay.
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I replaced the C961 electrolytic SMD capacitor (up side of the board, below the card slot and to the right) with a tantalum 100uF but I saw absolutely no improvement, not the slightest...
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then you may have a different issue
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Oh it is the jailbar issue allright... I have it on all my PCE type consoles. Its just that on the DUO it is more intense.
Just a question.... does the Sync signal (that Im getting straight from the chip) need amplification or not? Because right now I am amplifying it... I'm using the good amplifier that I made myself using the popular schematics http://www.pcenginefx.com/forums/index.php?topic=9299.0. I also used it on a bunch of other PCE consoles with good results but its the first time (the DUO) im using it taking all signals from the chip, i took the signals from the expansion port on all the others...
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No reply?
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I don't 'think' that it needs amplifying, and I don't think this would cause jailbars either way. I'm not 100% sure though as I've never used the amp that you're using, I've always been fine with the 3 x transistor method.
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Well the schematics also include an amplifier for the Sync (just sync and not composite sync) thats why I asked. I tried with and without sync amplification and the difference that I could notice was that WITH Sync amplification the colors were more "normal" and without the colors were more intense...
Jailbars were present in both cases in the same intensity but thats not the reason why I'm asking, its the colours Im worried about.
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sync is composite sync.
yes it will need amplification for most monitors as its only 0.3V not 5V (TTL)
its also not the jailbar issue.
2 things cause jailbars (power filtering) and (crosstalk)
some have had issues with region mod installs causing crosstalk.
the capacitor fix is for power filtering.
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Yes right, I got confused because in many mod schematics on the internet a lot of people show mixed up info. Some get composite (which i know does not need amlification) and indicate it as composite sync (which obviously does).
Could a weak sync signal cause incorrect colours or is it just my imagination?
As I said before, the 100uF tantalum cap did nothing for me that I could see. Maybe because my DUO is totally recapped recently and a difference is seen with old caps boards? Who knows...
I also have replaced the 7805 power regulator with a fresh one.
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a weak sync can cause color issues with composite.
PCE RGB does not match the colors PCE composite uses, due to the component blending not being even in the system stock
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I would like to ask your opinion about the most popular amp at this time I believe... http://imageshack.us/f/13/pcergb.jpg/
Is it a good amp from a technical point of view or is it flawed? Does it draw a lot of current or it's power consumption is negligible?
Well the results it produces according to my experience are excellent but just out of curiosity...
Im asking because on another forum someone was presenting this amp as an amateur cirquit drawing more power than the Hucard itself... ofcourse he could be just another a-hole...
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I'd like to know the answer to the above questions as well.
Would also like to know what the experts thought about the simpler 3 x transistor 1 x resistor method, as shown on mmmonkey.
http://www.mmmonkey.co.uk/console/pce/amp.htm
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that mmmonkey amp is seriously flawed, but closer to ideal in 1 way
the amp gtsamour showed is a good amp, just could be better
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How is the mmmonkey amp flawed Steve? I ask as I know of a lot of people using it (built into the SCART plug) and have never heard of any problems.
Also, Steve, don't you have a pre-made PCB amp available for sale, or is it bluebmw I'm thinking of? Either way, is a pre-made amp available from somewhere? I swear I recall reading something about it and seeing some pics of a prototype, just not sure if it ever eventuated into anything.
More importantly, what do you guys use for an amp?
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that mmmonkey amp is seriously flawed, but closer to ideal in 1 way
the amp gtsamour showed is a good amp, just could be better
There was this hypochondriac guy on another forum going crazy saying that its not a good amp, it doesn't have termination, it doesn't output the correct currents, it has high power consumption etc so it got me thinking.... is it true its not a good amp or is he stupid or something?
And if its not a good amp how could it have been published in a japanese book in 1988 and how come so many people still use it...
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the pc engine 1988 2sc1815 amp is a simple amp I certainly wouldn't call it a good amp. I've had issues with that amp in the past where other amps were fine.
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What kind of issues did you have?
Speaking for myself, I used this amp on 6 different (different kinds) PCEngines already and I got perfect results evereytime on more than one tv sets.
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the mmmonkey amp needs coupling caps on the outputs or voltage offsets on the inputs.
the 1988 amp is a basic video amp (not flawed in its basic design) it could just be mode more specific for the PCE signals.
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I thought it was made specificly for the PCEngine signals because the generic amp has 100 Ohm where the book's amp has 75 Ohm. Also the Sync part of the amp has 300 Ohm resistor. I hope I'm not forgeting something but maybe I am...
edit:
Here's the generic amp schematics http://tronixstuff.files.wordpress.com/2010/07/1txamp.jpg
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sync is composite sync.
yes it will need amplification for most monitors as its only 0.3V not 5V (TTL)
its also not the jailbar issue.
2 things cause jailbars (power filtering) and (crosstalk)
some have had issues with region mod installs causing crosstalk.
the capacitor fix is for power filtering.
I forgot to say my US Duo is region modded, any effective way to reduce crosstalk you mentioned? (if it is even an issue with my system) Although my system hasnt had a full cap swap yet, and could also be an issue, but I'm very close to being jailbar free, or virtually free
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caps are a big part.
you want the IC region mod
wires short as possible
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ok thanks for the info, shouldn't be the problem then. not looking forward to the cap replacement...
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My duo-r has problems with its region mod and jailbars on the rgb. i'm pretty sure its because the wires are way to long on the region mod. eventually when everything else i have being modded or fixed gets done, i will have steve straighten my duo out.
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I thought it was made specificly for the PCEngine signals because the generic amp has 100 Ohm where the book's amp has 75 Ohm. Also the Sync part of the amp has 300 Ohm resistor. I hope I'm not forgeting something but maybe I am...
edit:
Here's the generic amp schematics http://tronixstuff.files.wordpress.com/2010/07/1txamp.jpg
this amp is slightly better, but 100uf is too small for video
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solved
to solve jail-bar issue on rgb modded system replace capacitor C961 10uf with 100uf tant or 220uf aluminum.
the cap is from hu6260 pin43 to ground.
C142 on the TG16
Bumping this back up as I have a relevant question.
Anyone know if there is a corresponding cap to this in the Supergrafx?
I have installed the two tant caps from pins 41 and 43 to ground from the 6260, but curious if there is a similar cap to C961/C142 in the Supergrafx.
It looks like it might be C107 as it sits directly above the 6260 and is also a 10uF cap.
Thoughts?
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the 6260 does require a filter cap for each output circuit, so it must
couldnt tell you what cap without one in front of me
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Another quick question - where is the best place to tap 5 volts to power my NJM based amp? I'm going to stick the amp PCB over the HU card slot, as there is plenty of space there, and no heat sources.
Since you'll be sticking it over the HuCard slot, pin 38 on the slot would be an ideal place to grab 5V.
Thought I'd post a pic of the completed RGB mod:
(http://farm6.staticflickr.com/5558/14666933184_6b81a9d31f_b.jpg)PC Engine DUO with RGB Mod by ravij1, on Flickr
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Holy shit those are some thick wires.
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Holy shit those are some thick wires.
Used an old VGA monitor lead, the RGB leads are individually shielded. Overkill I'm sure :lol: