PCE RGB mod, disappointing results

city41 · 08/11/2013, 04:33 PM

Hey guys. I took a spare Tennokoe 2 and used it to do an RGB mod. So far I have not put an amp in, it's straight wires from the expansion port to jacks.

I have it hooked up to a Sony PVM 20M4U. I have a few questions:

-- Paranoia is bright as can be and is even brighter than what I get from composite. But Dungeon Explorer is so dark it's unplayable. Should I add the amp? Will that help DE and hurt Paranoia? Salamander is in between the two, it's on the dark side but not bad. Why am I seeing such different results per game?

-- The RGB is kind of blurry and just not that impressive. When I hook up my Neo Geo via component to the same monitor, it looks drop dead gorgeous. I was hoping for that same level of quality. Is the RGB out on a PCE just of a lower quality? Or is it the monitor? I have a few PCEs, and all of them give me the same results when hooked up. I have another PVM as well (20M2U), and both give about the same results.

-- When I switch from raw sync to composite video as sync, the quality improves a smidge. Is that expected?

all three images in a gallery

tennokoe RGB mod

CGQuarterly · 08/12/2013, 01:06 AM

TG16's and PCE's have gorgeous RGB pictures when the mod is done properly. You can't just decide not to put the amp in, and then call the results "disappointing."

HercTNT · 08/12/2013, 02:38 AM

Quote from: CGQuarterly on 08/12/2013, 01:06 AMTG16's and PCE's have gorgeous RGB pictures when the mod is done properly. You can't just decide not to put the amp in, and then call the results "disappointing."

Yup hehe

NightWolve · 08/12/2013, 05:22 AM

When I looked at any info about a NEC RGB mod, I only ever remember reading that the RGB signals are too weak for use from the 6260 chip or expansion port and need to be amplified, so I never heard of anyone just trying to use them directly...

city41 · 08/12/2013, 09:38 AM

gamesx mentions that the amp is not necessary:

QuoteIf you can get the parts and have the ability to assemble this amp, you won't regret it. For most monitors it's not necessary, though as mentioned above some won't sync without it. If you use an upscan convertor like the XRGB-2 you'll have a very acceptable image without the amp.

gamesx.com/rgbadd/duorgb.php

I guess you guys don't know the answers to my questions then. Thanks anyway. I'll add the amp and see what I get from there.

BlueBMW · 08/12/2013, 11:32 AM

Alternately you could try turbokons component mod

CGQuarterly · 08/12/2013, 02:44 PM

It's not that we don't know the answers to your questions. I have an RGB-modded PCE that I play on a Sony PVM. Every single game looks crisp, clear, and colorful. Yours apparently doesn't. My mod was done by the book, yours wasn't. Do I need to connect the dots for you?

Edit: my buddy has the exact same monitor as you, and everything looks fine on his, so since your Neo looks fine on yours, it isn't the monitor, either. I know that building the amp sucks, but just bite the bullet and do it, then let us know if you still have problems.

city41 · 08/12/2013, 03:04 PM

Quote from: CGQuarterly on 08/12/2013, 02:44 PMIt's not that we don't know the answers to your questions. I have an RGB-modded PCE that I play on a Sony PVM. Every single game looks crisp, clear, and colorful. Yours apparently doesn't. My mod was done by the book, yours wasn't. Do I need to connect the dots for you?

I gotta ask, what's with the attitude? Did I do something to offend you?

Several sites such as gamesx said the amp isn't necessarily required. So I thought I'd give it a shot. I'll build the amp this coming weekend and see what I get.

Quote from: BlueBMWAlternately you could try turbokons component mod

I thought about it. I think I'd rather go RGB though. Seems the component mod is more involved than the RGB amp to boot.

wildfruit · 08/12/2013, 03:17 PM

you can get rgb cables pre built that fit in the expansion port and are amped and output to a scart socket which is the route i will be taking as im not very handy but they are quite pricey
for my first go at modding im going to rgb my master system 2 doesnt matter so much if i muck it up

city41 · 08/12/2013, 03:28 PM

Quote from: wildfruit on 08/12/2013, 03:17 PMyou can get rgb cables pre built that fit in the expansion port and are amped and output to a scart socket which is the route i will be taking as im not very handy but they are quite pricey
for my first go at modding im going to rgb my master system 2 doesnt matter so much if i muck it up

I'm in a similar boat. The reason I modded the Tennokoe was so I could practice on something I don't care that much about. My true goal is to RGB mod my TG16.

For my Turbo I plan to add a din connector then just get the din->SCART cable from retro gaming cables. I can't use the expansion port as I have the CD attachment.

CGQuarterly · 08/12/2013, 03:50 PM

I'm not trying to give you attitude, but you did the mod without the amp, then complained about the picture quality. Then I pointed out that you didn't make the amp, someone else agreed, and you said "well, I guess you guys don't know the answers to my questions." I don't care what that page says on GamesX. Build the amp. I've never seen a TG16/PCE RGB mod done without one. Then, if you still have problems, we can hopefully help you troubleshoot them. And to answer your sync question, it should make no difference. I've tried switching from raw sync to composite video as sync, and I see no difference at all.

ApolloBoy · 08/12/2013, 05:25 PM

Quote from: city41 on 08/12/2013, 03:04 PMSeveral sites such as gamesx said the amp isn't necessarily required.

They're wrong, you definitely need an amp for RGB as the signals you get straight from the expansion port or HuC6260 aren't suitable. The PCE's RGB signals also have a huge DC offset which needs to be compensated for with a proper amp, as it could potentially damage either the PCE or your monitor.

I don't know if I'd consider GameSX as completely trustworthy either; they also say you can get RGB out of an N64 without an amp but in actuality the RGB is way too dim to be useable without an amp.

city41 · 08/12/2013, 09:33 PM

Quote from: CGQuarterly on 08/12/2013, 03:50 PMI'm not trying to give you attitude, but you did the mod without the amp, then complained about the picture quality.

Fair enough. Anyway, I'll make the amp hopefully this weekend and report back if I'm still having issues.

Thanks everyone!

turbokon · 08/12/2013, 10:58 PM

Like blue said, or you can just order my component video mod and get an amazing results:)

GohanX · 08/13/2013, 01:23 PM

It's not required, but the picture is going to suck without it. The only way it's going to look good is if you have a monitor/device that will allow you to adjust the signal level (thus acting as an amp for you) like a Framemeister or something.

I did the same thing with the N64 RGB mod. The amp wasn't required in it either, and it displayed a picture just fine but it pretty much sucked until I amped it.

city41 · 08/13/2013, 05:13 PM

Quote from: turbokon on 08/12/2013, 10:58 PMLike blue said, or you can just order my component video mod and get an amazing results:)

Your mod is really awesome. I totally would go that route, but I've already committed to RGB'ing up all my consoles.

turbokon · 08/13/2013, 08:08 PM

Does the pvm accepts component video? I never own a pvm before.

BlueBMW · 08/13/2013, 08:08 PM

Some PVMs do accept component video in addition to RGB, Svideo and composite.

CGQuarterly · 08/13/2013, 11:08 PM

The one city is using does. My friend has the same model. I have the BVM-20F1U, and it does, as well.

Tatsujin · 08/13/2013, 11:47 PM

Quote from: CGQuarterly on 08/12/2013, 03:50 PMI'm not trying to give you attitude, but you did the mod without the amp, then complained about the picture quality. Then I pointed out that you didn't make the amp, someone else agreed, and you said "well, I guess you guys don't know the answers to my questions." I don't care what that page says on GamesX. Build the amp. I've never seen a TG16/PCE RGB mod done without one. Then, if you still have problems, we can hopefully help you troubleshoot them. And to answer your sync question, it should make no difference. I've tried switching from raw sync to composite video as sync, and I see no difference at all.

QFT!!

city41 · 08/18/2013, 12:35 AM

I built the amp tonight. Well, I built an amp anyway. Not the most common one for the PCE, but rather this simpler one:

Works great! I'm getting a nice bright picture now. Dungeon Explorer now looks, well, as good as it can anyway

heh.

Just temporarily hooked it up in the Tennokoe. I'm not going forward with the Tennokoe, it was just a convenient place to try this out. I'm going to mount it in my Turbo.

CGQuarterly · 08/18/2013, 03:32 AM

I've built that amp before, then replaced it with an IC-based amp later on while troubleshooting a problem. I didn't notice a difference between the two.

Glad to see that you got it working to your satisfaction!

NightWolve · 08/18/2013, 09:21 PM

Quote from: city41 on 08/12/2013, 09:38 AMgamesx mentions that the amp is not necessary:

QuoteIf you can get the parts and have the ability to assemble this amp, you won't regret it. For most monitors it's not necessary, though as mentioned above some won't sync without it. If you use an upscan convertor like the XRGB-2 you'll have a very acceptable image without the amp.
gamesx.com/rgbadd/duorgb.php

I guess you guys don't know the answers to my questions then. Thanks anyway. I'll add the amp and see what I get from there.

Hm, I never noticed that (looks like they updated that page too, looks much better!), but it's terrible, lazy advice to just hook the pins straight from the chip to the TV/monitor and that goes for any other console unless you know the signal was properly prepared for TV/monitor output/usage and can handle the load...

The DC offset (as ApolloBoy mentioned) on the RGB pins is like 4.66 Volts and that 220 uF capacitor on the output in the full Japanese amp circuit filters that out. Also, the transistor works in a way where the signal behind it isn't attenuated at all when you plug it into a 75 Ohm load (TV/monitor or video converter device), though this doesn't quite matter with the 6260 chip so other video signals (Luma/Composite) don't get attenuated if plugged in at the same time. Anyway, those are good things to do or have, in other words. You wanna both protect the chip and prepare a proper, independent signal for the TV/monitor to process (thesteve could better explain, but yeah!).