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NEC TG-16/TE/TurboDuo => TG/PCE Repair/Mod Discussion => Topic started by: leonk on December 30, 2015, 07:28:47 AM
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Of all the RGB modded systems I've done over the past few years, none are as prone to vertical jailbars as the Turbo Duo / TG16. I've tried many different RGB amps and they all exhibit the exact same output. The jailbars are introduced into the video stream before the RGB amp. I would like to thank thesteve from pcenginefx forum for figuring most of this stuff out. He knows his obey stuff like no one else. Thanks dude.
Now onto the guide. There's actually multiple modifications you need to do to your Turbo Duo to get absolutely jailbar free RGB output.
1. HU6260 modification
(http://pic.photobucket.com/bwe.png)
As per http://pcengine.freeforums.org/jailbar-fix-t233.html you will need to add 2 capacitors to pin 41/42 and pin 43. (ignore the 3 wires - they're there for the RGB mod)
I used the following capacitors: http://www.digikey.com/product-search/en?keywords=1276-3300-1-ND - 22uF SMD ceramic capacitors. Rated at 16V.
2. C961 Capacitor
The original capacitor at this location is rated 10uF 16V. Replace it with a 220uF 16V capacitor
Digikey link: http://www.digikey.com/product-search/en?keywords=493-5357-1-ND
3. Better grounding on 8 pin DIN port
(http://pic.photobucket.com/bwe.png)
If you replaced the stock 5 pin DIN port with an 8 pin DIN port, you need to improve the grounding. As is, the GND pin goes though a choke. You need to bypass the choke. Because the ground is shared by all the other pins, the choke causes inverted crosstalk.
The results: (please ignore the horizontal lines - it's hard to capture a good picture off a CRT / Sony PVM).
Before: (note the vertical jail bars in the sky)
(http://pic.photobucket.com/bwe.png)
After: (all clean!!)
(http://pic.photobucket.com/bwe.png)
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Just curious if you use regular composite for video or pure sync from the Hu6260 chip?
Also, are you using a TV that accepts a scart input or a device that converts it to a component or HDMI signal?
I've noticed that the severity of jail bars can sometime depend on the device being used to convert the signal.
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he said sony PVM
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he said sony PVM
My mistake. Accidentally skimmed past that part. Hard to see stuff sometimes on my phone.
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That's correct, it a Sony 20" PVM. I use an 8 pin DIN in place of the original 5 pin on the black Duo. I wanted to make sure all original cables still work, so there is no CSYNC at the adapter, the PVM uses composite video sync.
The cable connects to a female SCART connector that goes to RCA audio + BNC R/G/B/Sync into the TV.
Thesteve .. thanks for answering all my PM's!!
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Will it also improve composhit or S-Video as well? Cheap mod to try anyhow and I do have 220uF cap sitting around. I need to get a couple tiny SMD caps though.
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thanks for documenting leonk. Has anyone tried these other places that Otaku store has for larger caps?:
http://www.otakus-store.net/en/content/6-guide-nec-rgb
wondering if those help
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The two 22up caps usually fix the jail bars for me when component modding a duo. The turbografx-16 is another story. What's the equivalent cap to C961 for the tg16?
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I just wanted to post and say that I've done everything mentioned to remove the jail bars and it does not completely get rid of them for me. Especially in games like JJ and Jeff or Keith courage. slight jail bars and sort of a very minor checkerboard pattern can be seen in the background.
what takes care of it on my end along with all the modifications mentioned above is using pure sync off of the video chip instead of regular composite video for sync. Maybe it's the type of scart to HDMI converter I am using because I do not own a Sony pvm.
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Is using pure sync for use on a CRT TV OK? Or does it depend on the TV? I was thinking of cutting the sync pin on the DIN8 and linking pin 44 to it rather than using the composite video. I will also be doing what is suggested in the thread. Jailbars are evil. Now if I could get rid of that horrible "mesh" effect the PCE has, that would be even better!
P.S. I am drooling at the sight of Wataru in RGB on a PVM. Damn those things are gorgeous!
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you can cut that trace and run pin 44 over to it as you said. however, in doing so you would no longer be able to use a regular AV cable for composite video in the future if you ever wanted to. if you want the option to use both pure sync or composite sync when wanted then simply install a switch to swap between the two.
Larger switch is a region switch. Smaller switch on the right is for composite/pure sync switch.
(http://s17.postimg.org/i4x1oi4ez/CIMG8694.jpg) (http://postimg.org/image/i4x1oi4ez/)
Using pure sync may not be needed depending on your setup. As for me it is needed with the scart to HDMI converter I use. Otherwise jailbars/checkerboard pattern is displayed.
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Do you use SYNC straight from pin 44 to the din socket? I thought it needed amplification?
I get the mesh effect when I use comp video for sync on an original PC Engine, but not on the other consoles that have comp video (din 5) output as standard.
The jailbars seem worse on the din 5 consoles than the original PC Engine though.
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thanks for documenting leonk. Has anyone tried these other places that Otaku store has for larger caps?:
http://www.otakus-store.net/en/content/6-guide-nec-rgb
wondering if those help
Today I replaced the C103 cap for a 1000uf one in :
- a non-modded Core1.
- a RGB modded Core1.
I hooked them to an RGB modified IFU plugged to a Sony CRT TV via scart cable. I had a significant reduction of the jailbars with both.
Then I tested the 2 syncs with RGB Core alone, RGB Core+IFU, and non-RGB Core with IFU.
Game tested: Wataru/Keith Courage.
- Using Csync, jailbars are almost totally unnoticeable, if not totally, but the very first deep blue screen just before the light blue title screen is a little blurish.
- Using composite video, that first deep blue screen is perfect but they're still some very light jailbars noticeable in the first level, but very heavily reduced. The image is a little less sharper when scrolling than when using Csync too.
I got the same results with the RGB Core alone and both Cores hooked to the IFU. So as this deep blue screen is the only one I got among the games I tested so far, I let the IFU wired with Csync.
Does anyone have an idea about that blurred screen?
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Do you use SYNC straight from pin 44 to the din socket? I thought it needed amplification?
I get the mesh effect when I use comp video for sync on an original PC Engine, but not on the other consoles that have comp video (din 5) output as standard.
The jailbars seem worse on the din 5 consoles than the original PC Engine though.
no amplification needed. Basically you cut the trace for the composite signal at the a/v jack and tap pin 44 from the video chip to it instead. or wire up a switch you can change between the two.
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As KC already mentioned, CSYNC vs Composite Video sync very much depends on your display device. Luckily, PVMs can sync on CSYNC, composite video, luma and even sync on green!
I was wondering, if someone uses composite video sync SCART cables with a sync stripper in the SCART end, will it show the same result as real CSYNC? If so, the sync switch will not be needed!
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FYI, I've had a little guide for this based on Steve's last findings.
http://www.pcenginefx.com/forums/index.php?topic=13231.0
(http://i237.photobucket.com/albums/ff216/Sephiroth1975/Tech/NEC6260JailBarFix.jpg)
You've added 2 additional tasks of replacing en existing capacitor and adding a jumper wire for additional grounding. The tip of grounding your video circuit back to pins 55+56 is also another difference I see that you didn't try or know about. If there's further confirmation of what helps, I can update the photo some time but generally I just prefer going with Le Stevo's findings/research.
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i can confirm what he did was based on my findings
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Because there is no pre-wired sync when connecting a DIN8 to an IFU, I am going to try pure SYNC first to see how it works on a few different TVs. I will only be using it on RGB SCART TVs, and I know that some TVs will only use composite sync. I am tempted to just cut the trace and link pin 44 directly to the sync pin on the DUOs because I have no need for composhite, but I may leave it incase I ever want to sell one. OR I may add a switch as Keith suggested. If the pure sync from the IFU is OK, that will make the descision harder. Great info in this thread, thanks to you all!
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Hey NightWolf, thanks for the pic. Couple of personal suggestions:
- those are ceramic capacitors. They have no polarity. Assigning +/- makes no sense. I would actually emphesize to purchase +/- 20% caps rather than than ones that go up to 80%
- ground is ground. There's no such thing as better ground than another one. If you had "different" grounds you'd have a potential difference. Bad things happen in circuit boards (shorts, fires, death) :)
I think the massive ground plain which the caps connect to now is sufficient.
Csync vs other syncs issues is not native to NEC consoles. Other RGB modded consoles have similar issues. The "fix" discussed in this thread simply puts the Duo on the same playing field as others. Whichever solution one uses for sync on other consoles should employ here as well.
Personally, I'm not a fan of taking functionality away. removing composite video makes no sense to me. There is another solution. But will require custom cables:
- remove L/R audio from DIN
- add csync to new vacant pin
- add 3.5mm jack for stereo
You basically recreated a Sega Genesis Model 1. Audio (theoretically) will sound better as it will have its own seperate path rather than crammed in with everything else.
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errrm, massive noob question... When installing the ceramic caps on 41 and 43, does one scratch off the green masking to reveal copper to which the ceramic is soldered to?
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Yep, really hard to solder to otherwise ;)
I use a scapel to scrape it off but you can buy fibreglass pens which are the 'proper' tool...
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Yep, really hard to solder to otherwise ;)
I use a scapel to scrape it off but you can buy fibreglass pens which are the 'proper' tool...
Hahaha, thanks! :D
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I have mu duo-r rgb modded and thesteve did a bunch of stuff but i still have jailbars. not sure if this would fix my problem or not? its most notable in blue colors. i am using two different son pvm models with mickcris' scart cable. no idea what rgb mod thesteve used on it though
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- those are ceramic capacitors. They have no polarity. Assigning +/- makes no sense. I would actually emphesize to purchase +/- 20% caps rather than than ones that go up to 80%
In that photo, yes, but some people use tantalums or others which ARE polarized so the labeling is still provided for whatever capacitors you do have, polarized or not. Why would I take away the labeling just for the one case used there ? That would not make sense, more info is better and helpful for noobs starting out...
Steve has taught people plenty of times on the ease of ceramics, though they do get expensive going up from these ranges. I also have a mistrust of them since a prior digikey purchase. I bought four 100 uF capacitors for my SNES but all of them only measured 60 uF when tested. All the 10 uF ones I bought were good showing 9.X uF when tested. Steve thinks I just got a really bad batch that time. It does seem like they clock in lower usually compared to other types.
http://www.pcenginefx.com/forums/index.php?topic=13231.msg287992#msg287992
In the above photo in the link, polarized models are used.
- ground is ground. There's no such thing as better ground than another one. If you had "different" grounds you'd have a potential difference. Bad things happen in circuit boards (shorts, fires, death) :)
I think the massive ground plain which the caps connect to now is sufficient.
I have to check who made that finding. I'll see what Steve says about it.
errrm, massive noob question... When installing the ceramic caps on 41 and 43, does one scratch off the green masking to reveal copper to which the ceramic is soldered to?
Yeah, that is a massive noob question. ;) Of course, no bond or conductivity can occur if you don't.
Also, you can use tantalum capacitors if you have 'em, just mind the polarity in that case.
EDIT: On tapping ground from pins 55+56, that was a Steve recommendation and also is shown in an online RGB mod video.
http://www.pcenginefx.com/forums/index.php?topic=13231.msg301235#msg301235
Keith Courage once noted that ground from pins 55+56 made the jailbar situation worse for one of the models he was modding though. But Steve thinks the grounding was bad to the chip so that's an oddball case.
I can't agree with the statement, "Ground is ground. There's no such thing as better ground than another one." That'd be like saying the same thing about the best place to tap the +5V source which is the output leg of the regulator versus from the A/V output. Anywhere else, you're adding the resistance of the traces and causing a voltage drop. And as we know, tapping from the regulator leg solves the problem with those powered region mods when using flashcarts.
The same thing about resistance and interference or whatever else should apply on determining the best place to tap ground as it does for the +5V source in principle.
EDITx2: Also, ConHuevos solved jailbars on his model with 220 uF caps in parallel to .1 uF as it didn't work with 22 uF for him.
http://www.pcenginefx.com/forums/index.php?topic=13231.msg320288#msg320288
(http://i.imgur.com/Uh502z0.png)
So, more things to try if the main suggestions don't help, FYI to others.
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on the ground case, remember that every wire, and every trace has both resistance and inductance
the resistance is negligible in most cases, but the inductance can play hell with square wave currents, such as any digital signal
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I did this mod to my USA TG16. It uses Tim Worthington's AV Driver as the RGB amp. I added the 2 ceramic caps to pins 41/42 and pin 43. I also replaced C142 with a 220uF cap.
The jailbars went from very visible (same as on Turbo Duo) down to 2-5% visible. You need to look for them hard, but you'll find them. Regular players will never see them during normal game play. On Turbo Duo I simply can't find them in the same spots.
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thanks for documenting leonk. Has anyone tried these other places that Otaku store has for larger caps?:
http://www.otakus-store.net/en/content/6-guide-nec-rgb
wondering if those help
I just did this extra capacitor mod for a JP PC Engine DUO. It works great. No jail bars whatsoever now. Just installed the one larger cap in the picture. Website did not say the value of the capacitor but from the length/width of it I'm guessing that it's a 820UF or 1000UF cap. I haven't seen many lower value caps that are that tall and skinny.
(http://www.otakus-store.net/img/cms/Pose_DUO.html)
Adding this 1000UF cap is the only thing I changed. Did not have to add the two 22uf caps nor did I have to do anything extra with grounding.
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Oh wow, very good find, mickcris! That's a purty thorough mod guide, we should note it somewhere more permanent like say in one of the sticky threads, etc. The site offers cap kits and other guides in decent presentation too.
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thanks for documenting leonk. Has anyone tried these other places that Otaku store has for larger caps?:
http://www.otakus-store.net/en/content/6-guide-nec-rgb
wondering if those help
I just did this extra capacitor mod for a JP PC Engine DUO. It works great. No jail bars whatsoever now. Just installed the one larger cap in the picture. Website did not say the value of the capacitor but from the length/width of it I'm guessing that it's a 820UF or 1000UF cap. I haven't seen many lower value caps that are that tall and skinny.
(http://www.otakus-store.net/img/cms/Pose_DUO.html)
Adding this 1000UF cap is the only thing I changed. Did not have to add the two 22uf caps nor did I have to do anything extra with grounding.
thats the same place as one of viletim's fix caps go. he had stated that a ceramic cap is needed though. wondering if that large cap might work the same or better. the small ceramic is probably easier to put in though.
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if anything the 1000uf is overkill
ceramics tend to have better response, but if anything the 1000uf aluminimum will do at least as well as 100uf of ceramic