TurboGrafx 16 RGB Mod with XRGB-Mini Issues

[lechu]

I just modded my TG-16 for RGB out through a Sega Genesis model 2 port. The mod worked perfectly. I know this because I tested it out on my Broadcast monitor. It looks stellar on that monitor. However...

The XRGB Mini has given me nothing but problems with it. I have it hook up through Euroscart to a Euroscart to Mini adapter with a Sync Stripper built in. When it's hooked up that way, there's a yellow tint over everything. Basically, all the whites look like a light yellow. This has never happened with any of my other consoles before, and I have about 5 that go through that adapter with no issues.

I thought that the mod might not like the sync stripper, so I tried with a passive adapter. Turns out it must really like that sync stripper, since I don't get any picture through the passive adapter at all.

I have no idea what to do. For reference, here's the mod I used: http://www.tg16pcemods.com/rgb-amp.html

[mvsfan]

IT almost sounds like your scart cable has a poor connection, or mabeye that adapter does.

Personally, i dislike scart because its hard to find a good scart switch and good sockets that the plugs dont fall out of. I still use scart though, you just have to find good socket not the junk they sell most of the time on ebay.

Really, someone should offer Console to BNC cables instead of scart. Extron Crosspoint Rgb switches are awesome and easily found, and they use BNC.

[lechu]

IT almost sounds like your scart cable has a poor connection, or mabeye that adapter does.

Personally, i dislike scart because its hard to find a good scart switch and good sockets that the plugs dont fall out of. I still use scart though, you just have to find good socket not the junk they sell most of the time on ebay.

Really, someone should offer Console to BNC cables instead of scart. Extron Crosspoint Rgb switches are awesome and easily found, and they use BNC.

I don't think it's the connector. The TG-16 works with the Monitor. The Genesis 2 cable works with a Genesis through the Framemeister. All my other scart consoles work with the Framemeister. It just doesn't like the whites on the TG-16.

I hate scart too. I just like the video quality haha

[mickcris]

your scart cable probably has caps and resistors in it and that amp does also. not sure if that would cause the issue, but you should remove them from one of them.

[RGB32E]

your scart cable probably has caps and resistors in it and that amp does also. not sure if that would cause the issue, but you should remove them from one of them.

As discussed elsewhere, using just about any Sega RGB cable for another system is always a poor decision. Then again, this is a Shawn Yith product, so expectations should be set low. I discovered various outdated/misinformation in the installation manual. While it was nice that he lifted Tim's info for fixing jail bars, he lists it as "optional", and even includes the outdated "theSteve" information for how not to quite solve the problem on Duo systems (*facetopalm*).

I don't think it's the connector. The TG-16 works with the Monitor. The Genesis 2 cable works with a Genesis through the Framemeister. All my other scart consoles work with the Framemeister. It just doesn't like the whites on the TG-16.

I hate scart too. I just like the video quality haha

Are you using sync directly from the expansion connector? Did you leave the 75 ohm resistors on the awful RGB amp Shawn sold you? Genesis 2 RGB cables generally have both 75 ohm and 220uF capacitors contained, and typically cable builders leave out the 470 ohm and 220 uF capacitors on the SYNC line that are needed to make the signal 75 ohm compatible (what the XRGB-mini and others expect). The audio and sync signals need to be buffered before being output from the system and that amp does not address. Hence, Yith's RGB amp is a half assed solution (typical) and you should contact Tim W for an AV-DRIVER to use instead. Also, use a 8 MDIN connector for output with the XRGB-mini pinout instead of a 9 MDIN Sega.

If you want to learn more as to why Sega RGB cables are a poor choice for systems they were not designed for, read this!

http://shmups.system11.org/viewtopic.ph ... 1#p1123571

[lechu]

your scart cable probably has caps and resistors in it and that amp does also. not sure if that would cause the issue, but you should remove them from one of them.

As discussed elsewhere, using just about any Sega RGB cable for another system is always a poor decision. Then again, this is a Shawn Yith product, so expectations should be set low. I discovered various outdated/misinformation in the installation manual. While it was nice that he lifted Tim's info for fixing jail bars, he lists it as "optional", and even includes the outdated "theSteve" information for how not to quite solve the problem on Duo systems (*facetopalm*).

I don't think it's the connector. The TG-16 works with the Monitor. The Genesis 2 cable works with a Genesis through the Framemeister. All my other scart consoles work with the Framemeister. It just doesn't like the whites on the TG-16.

I hate scart too. I just like the video quality haha

Are you using sync directly from the expansion connector? Did you leave the 75 ohm resistors on the awful RGB amp Shawn sold you? Genesis 2 RGB cables generally have both 75 ohm and 220uF capacitors contained, and typically cable builders leave out the 470 ohm and 220 uF capacitors on the SYNC line that are needed to make the signal 75 ohm compatible (what the XRGB-mini and others expect). The audio and sync signals need to be buffered before being output from the system and that amp does not address. Hence, Yith's RGB amp is a half assed solution (typical) and you should contact Tim W for an AV-DRIVER to use instead. Also, use a 8 MDIN connector for output with the XRGB-mini pinout instead of a 9 MDIN Sega.

If you want to learn more as to why Sega RGB cables are a poor choice for systems they were not designed for, read this!

http://shmups.system11.org/viewtopic.ph ... 1#p1123571

Ok, so admittedly, I'm a bit of a noob when it comes to modding. I just used his RGB amp because it looked easy (have to start somewhere). I using the sync straight from the expansion port. I haven't altered the RGB amp at all. I bought the Sega cable from retrogamingcables.co.uk.

I opened up the scart connector, and it looks a bit different than this pinout:http://members.optusnet.com.au/eviltim/ ... /mega2.png

The RGB lines have heat shrink on them, but it doesn't look like there are capacitors. There is a 220 uF capacitor and a resistor on pin 20. I think that's what you said needs to be there. And there are wires going to pins 18 and 4 (grounds perhaps? again, I'm a noob).

So, I'm guessing it may be the missing capacitors on the RGB lines. Would that work? And should I remove the resistors from the scart cable (or modboard, but the cable would be easier)?

[mickcris]

i had not looked at the guide for that amp, and did not notice that it was recommended to use that cable. it looks like from the in the pic, it does have the 75 ohm resistors already on the board but maybe those are on the input side for some reason? it defiantly doesn't have the 220uF caps on the board though. it says you can use that cable without modification so I dont know.

[lechu]

i had not looked at the guide for that amp, and did not notice that it was recommended to use that cable. it looks like from the in the pic, it does have the 75 ohm resistors already on the board but maybe those are on the input side for some reason? it defiantly doesn't have the 220uF caps on the board though. it says you can use that cable without modification so I dont know.

I gave it a shot. Not only did it not fix the issue with the XRGB Mini, but now the yellow tint is on the monitor. Fuck. I'm going to buy some resistors tomorrow (since one of them broke when trying to remove them), and try having caps and resistors in my scart cable.

[lechu]

i had not looked at the guide for that amp, and did not notice that it was recommended to use that cable. it looks like from the in the pic, it does have the 75 ohm resistors already on the board but maybe those are on the input side for some reason? it defiantly doesn't have the 220uF caps on the board though. it says you can use that cable without modification so I dont know.

I gave it a shot. Not only did it not fix the issue with the XRGB Mini, but now the yellow tint is on the monitor. Fuck. I'm going to buy some resistors tomorrow (since one of them broke when trying to remove them), and try having caps and resistors in my scart cable.

Update time:

I put in caps and resistors, still have the same problem. I finally thought of turning on my CRT R G B only modes. R and G worked. Nothing on B. So there's some problem with the blues on this console or mod. I've done every possible continuity check I can think of, but I'm not finding this issue. I have no idea where to go from here.

[RGB32E]

Care to share pictures? Have you verified that the Genesis 2 RGB cable works OK with a Genesis 2?

You could also try swapping the blue connections to the amp with red or green (using the respective in/out) and see if you still have an issue with blue. Could be a bad NJM2267 amp or a wiring issue you haven't caught.

You can technically use the fourth input for sync so that you can use a passive adapter (or a number of other things), but you'd have to hack that into the existing kit, and doesn't appear to be related to the blue video issue (separate "issue"). I built and used a NJM2267 based amp before switching to a THS7374, and currently Tim's AV-DRIVER.

[viletim]

I thought that the mod might not like the sync stripper, so I tried with a passive adapter. Turns out it must really like that sync stripper, since I don't get any picture through the passive adapter at all.

I have no idea what to do. For reference, here's the mod I used: http://www.tg16pcemods.com/rgb-amp.html

The original PC Engine (white one) and Turbografx 16 consoles don't have any composite video output it's RF only. RGB video is FOUR SIGNALS NOT THREE. The fourth channel is need for the sync (or composite video). You can't just connect the sync output of the graphics chip to a cable (which is driving a 75 ohm load) and expect it to work. This crap amplifier PCB is not fit for purpose because hasn't got sync amplifier/driver. The use of the Mega Drive SCART cable is a bad idea too.

[lechu]

Based on multiple recommendations, I'm scrapping the Genesis cable entirely for this mod. If I'm going to do it, I'm going to do it right. Plus the particular connector I was using is such a bitch to solder to haha. I'm going to switch to the 8 pin mini Din. I placed an order for stuff from Tim's website, and I bought one of those anyways (thanks Tim). I think I may just redo with a whole different mod, since everyone is saying this PCB is shit. $20 down the drain, but you live and learn.

I know this is basically a new topic, but what's the best RGB mod for the TG-16? I see a bunch of people saying Tim's AV Driver, but I don't see it anywhere on his website. I've used the THS7374 chip for an N64 RGB mod before. Is it a similar mod?

Thanks for all the help folks.

[kamiboy]

Tim's amp is its own little thing. You have to contact him personally to put in an order for it since it is not officially available yet, just for those with insider knowledge.

[lechu]

Well, I eventually solved the problem. Turns out there was no blue coming from the blue output spot on the board... at all. I have no clue why it worked at first on the CRT. Either way, I took the blue from a different spot on the pcd board and it fixed everything. I'm still going to use the AV Driver and Mini 8 Pin Din though when I order them from Mr. Worthington. Again, I'd rather get this mod done right. This board will just be temporary.

Thanks for all the help.