Messages

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

Ah, good eye.  I did make a typo.  Hmmm... I've got some time to kill this morning and if that works it would be an easy fix, I think I'll try right now and see if that was the problem.

EDIT: Nope.  That wasn't the only problem apparently.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

Darn.  I tested my build a little while ago and it didn't work.  I'll have to go back in and double check everything I guess.  Seems odd since I was very careful and triple checked everything (wiring, continuity, etc.) before I installed.  Ah, well.  I just hope I really got the schematic right.

I wonder if it has something to do with grounding all the components to the PCB w/ one wire, or maybe 0.30 gauge kynar wire isn't thick enough for connecting the CXA1645 (I didn't use kynar for the grounds or input voltage to the CXA1645 or any of the other components though)?  Maybe I should have routed 2 separate grounds for the s-video plug instead of piggybacking them?  Hmm...

LOL it was fun ripping into the PCB and top shield with a dremel tool though (as it turns out I needed the carve out the spot where the RF unit was to get the s-video socket to fit with the case closed).

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

OK, thanks.  I think I'll just put the bottom shielding back on then.  There is a transistor which appears to be grounded through the shielding and I think it's screwed to the bottom half.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

Argh.  Another day without Turbo s-video goodness.  I accidentally picked up 0.001uF caps instead of 0.01.    I ordered some from mouser, but am hoping Fry's Electronics will have some when I stop by there this evening so I can be playing by this weekend.

I did however finish adding composite/RCA jacks (figured I may as well do both since s-video isn't very common), removing the RF hardware and putting the s-video jack in its place (which looks very nice and fits perfectly as long as you mount it upside-down -- otherwise the cable won't fit in properly because of the shape of the hole), and organizing the layout of the project board.  Would be nice to have something to cover the hole where the channel selector was but I can live with the one little imperfection.

Too bad I can't find a 8PDT switch to do a region mod though (other than a push on/off type that requires 2 5/8"+ clearance behind it, which I don't quite have).  And I was going to do an LED mod (thought it would look cool to have a blue LED shining from behind the Hu slot) but I'm starting to wonder if it would shine through the Hu slot gap enough to justify bothering with it. 

Oh, and does anybody know if I need to reattach the shielding to the PCB if I removed the RF unit?  Isn't RF interference the primary reason for the shielding?  I probably will put it back on anyways but if I can leave it off it would probably be easier to fit the project board in and reassemble everything.  Plus I pryed off several of the grounding pads and would have to use flux paste to attach the shielding to some new grounding points (which I'm not looking forward to ).

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

Awesome.  I may have to try to get this built today then since I've nothing better to do (assuming the good electronics store downtown has LM1881s and proper crystals).  Once I test the build I'll take the "draft" markings off the schematic and maybe do a nice write-up in an HTML doc to send to gamesx.com.  Is there anyone else who needs to be credited besides you?  Did D-Lite help you, or anyone else?

I do have another question, though.  I was thinking I might get a real Duo soon (there is a sweet package on eBay ending soon I might splurge on) to replace my Turbo Grafx unit, at which point I'll order another CXA1645M so I can mod both... but before I order just 1 more chip would this mod work with other systems with the appropriate inputs available?  This seems to be a general purpose circuit and I was thinking it might be pretty sweet to put one of these in the ol' NES2, SNES mini, or Genesis1/CD/32X stack (well maybe not the latter since I'd probably have to mod all 3 units).  If so I'm also guessing I might not even need the LM1881 for some other systems...?

And thanks for the welcome, not sure if I'll end up being a big poster here but it's good to see an active board dedicated to the Turbo and its various incarnations.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

OK.  Here is the first draft of what I would assume is the complete s-video conversion circuit.  I think I screwed up on one part (see NOTE) and should have shown vertical sync (pin 3 of the LM1881) routing to pin 10 of the CXA1645M instead of composite sync (pin 1 of the LM1881).  I left it as-is for now, though.

Can anyone confirm if this schematic appears to be laid out correctly?  grahf?

Thanks.

NOTE: Like the diagram says, I don't know if this is laid out correctly, DO NOT attempt to build this circuit as-is.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

I haven't finished yet but I've started on an attempt to make a schematic.  When I'm done I'll post it here so grahf can (maybe?) look it over and make advisements.

And while I'm posting can anyone recommend a resource that sells both the LM1881N and the ECS-2100AX @ 3.579545MHz (or a substitution for the LM1881N)?  I'm trying to avoid ordering the former from jameco and the latter (plus the other misc. parts) from mouser.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

Any help you can offer would be appreciated.  In the meantime I'll try to figure things out myself and will make a schematic of my own.  If I can figure most of it out maybe you can look it over and help me make some corrections instead of having to make a schematic yourself.

And if anyone else is interested I made an offer of $13.95 for a CXA1645M from a seller on eBay (the only guy who is selling these chips right now) and he accepted, so if anyone else wants to try the same thing you can probably get the chip for $20 even shipped.

[Console Repair/Mod Center / Re: complete DUO S-Video mod]

To whoever eventually makes a schematic of this: you are my hero.

So is this mod pretty much as simple as providing the needed inputs as directed on the datasheet (not including the input from the crystal), then routing the output?  If so I may have to try this out.

I wonder if there would be room for the s-video mod, a region mod, and composite output (RCA) in a regular old US Turbo Grafx-16?  I guess I could always remove the RF modulator and some of the casing/shielding...