NESRGB help

Hello everyone!

So I've finally got the NESRGB mounted and installed and I'm now experiencing garbled graphics when I turn it on. I've tested several 72-pin connectors which didn't resolve the issue and put the PPU in a non-modded console, which fired up fine (no garbled graphics).

One thing I do find odd is that I don't get RGB output through the 8-pin din unless I also have at least one of the A/V composite (audio or video) plugged into the framemeister as well. The framemeister's input is RGB, so it's pretty strange that I get no output on that until I also plug in the composite a/v (I get no output if I switch the framemeister to video in).

Curious if anyone has an idea where to start troubleshooting, because following Tim's install guide to a T has yielded no results, sadly. Here are some photos if they help:

 

I don't know how the Framemeister handles sync, but I'm wondering if the issue of not having video unless the composite cable is plugged in has to do with an error in wiring up the sync signal to the mini din.

Have you made sure that the pin headers are making good contact with the socket you installed on the NES PCB? Similarly, have you checked continuity between the legs of the PPU and the ends of the pins that go into the socket?

 

I wired up R, G, B, 5v, and composite sync as per the wiring diagram that Tim provided on his site (found here: http://etim.net.au/nesrgb/installation-nes/NESRGB-Wiring_Diagram-NES.pdf ). It is pretty strange.

I'll have to check them with a multimeter, but upon just visual inspection, there are no bridged solder points and everything looks like it's pretty secure. I'll let you know what I find.

 

The NESRGB has a few options for sync:
http://etim.net.au/nesrgb/rgb_connector.htm

The way he has it shown in the wiring diagram is taking sync via the composite video signal (which isn't the same as composite sync, or CS# on the NESRGB PCB). I do not own a Framemeister, so maybe check which kind of sync signal it needs.

 

Ah, that's a good point. Maybe I should try using the CS# instead of the V pad?

 

Might be worth a shot. Another option is to try PPUV for sync.

http://shmups.system11.org/viewtopic.php?f=6&t=49677

 

That actually fixed the issue of needing composite video connected!. Just used the cs# pad instead.

Now to trace down where the garbled graphics are coming from and I'll be all set.

Thanks for the idea! Been sick all day, but want to troubleshoot this down.

 

Glad that worked.

Are you getting sound despite the garbled graphics? Or, to put it more directly, are games actually playing?

 

I don't have sound hooked up yet, so I can't say. I'll test that as well.

 

Oops, looks like you replied before I managed to edit my post. Are the games playing despite the garbled graphics, or is it just a frozen screen of garbage?

 

Oh, yes. I was able to load Phantom Fighter and play it, despite the garbled graphics.

 

OK, since you said that the PPU tested good in another console, then I'd definitely check continuity between the legs of the PPU and the header pins coming off of the NESRGB (after you double check to make sure that it isn't something really simple like the header pins not connecting properly into the socket on the NES motherboard or something).

EDIT: Also make sure that the socket is fully soldered into the NES motherboard.

 

Woo! Figured out the issue! One of the pins on the PPU wasn't soldered completely upon further examination.

Thanks for being the sanity check on this!

 

Glad it worked out! Have fun.

 

I normally wouldn't attempt to hijack a thread like this but since digitalia has resolved his issue, I figured it couldn't hurt!

I attempted my first NESRGB mod last night & I'm getting garbled graphics. I had issues removing the PPU from the NES motherboard so I have a feeling I might have fried it - had to desolder several legs multiple times. Here's what I'm getting via s-video:
http://imgur.com/t5co5SS
http://imgur.com/ynZScJr

Composite output (via the NES's RF module) is very similar except there's no color.

Is this PPU definitely fried? Are there any things that I can try aside from putting this PPU in another NES? Any help would be greatly appreciated! Thanks!

 

The PPU may not be properly soldered (which was my issue). I would re-do every pin and see if that resolves it. Trust me, mine looked good, but I think I had a bad/cold solder joint on one of my pins.

 

After reading this topic last night, I tried exactly that. I probably should have mentioned that in my previous post haha. Unfortunately the output did not change . It's always the same kind of garbled image. I should also mention that this 72-pin connector works perfectly in another NES & worked perfectly in this NES prior to the mod.

EDIT: I'm considering removing the PPU from the NESRGB & checking the connections on the header pins that connect to the socket on the motherboard next.

 

Oh, well.. I'm assuming you don't have another PPU to test? Do you have a multimeter to test continuity between the pins?

 

I don't have another PPU to test yet. I've ordered a few more NES' to play with but they won't be here until next week.

I do have a multimeter though! Just to verify, each pin on the PPU should have continuity to the corresponding pin on the headers correct?

 

Set the multimeter to continuity mode. Test the continuity of the PPU signals between the PPU and the base of the NES motherboard. All pins connect straight through except 2-9 and 14-17. If a continuity is not present when it should be this indicates a bad solder joint (or bad pin).

I think this correct, anyway. Hopefully someone with a little more experience can verify this.