Can anyone improve the rgb output on my duo?

[gtsamour]

I thought it was made specificly for the PCEngine signals because the generic amp has 100 Ohm where the book's amp has 75 Ohm. Also the Sync part of the amp has 300 Ohm resistor. I hope I'm not forgeting something but maybe I am...

edit:
Here's the generic amp schematics http://tronixstuff.files.wordpress.com/2010/07/1txamp.jpg

[incrediblehark]

sync is composite sync.
yes it will need amplification for most monitors as its only 0.3V not 5V (TTL)
its also not the jailbar issue.
2 things cause jailbars (power filtering) and (crosstalk)
some have had issues with region mod installs causing crosstalk.
the capacitor fix is for power filtering.

I forgot to say my US Duo is region modded, any effective way to reduce crosstalk you mentioned? (if it is even an issue with my system) Although my system hasnt had a full cap swap yet, and could also be an issue, but I'm very close to being jailbar free, or virtually free

[thesteve]

caps are a big part.
you want the IC region mod
wires short as possible

[incrediblehark]

ok thanks for the info, shouldn't be the problem then. not looking forward to the cap replacement...

[HercTNT]

My duo-r has problems with its region mod and jailbars on the rgb. i'm pretty sure its because the wires are way to long on the region mod. eventually when everything else i have being modded or fixed gets done, i will have steve straighten my duo out.

[thesteve]

I thought it was made specificly for the PCEngine signals because the generic amp has 100 Ohm where the book's amp has 75 Ohm. Also the Sync part of the amp has 300 Ohm resistor. I hope I'm not forgeting something but maybe I am...

edit:
Here's the generic amp schematics http://tronixstuff.files.wordpress.com/2010/07/1txamp.jpg

this amp is slightly better, but 100uf is too small for video

[broken]

solved


to solve jail-bar issue on rgb modded system replace capacitor C961 10uf with 100uf tant or 220uf aluminum.
the cap is from hu6260 pin43 to ground.
C142 on the TG16

Bumping this back up as I have a relevant question.

Anyone know if there is a corresponding cap to this in the Supergrafx?


I have installed the two tant caps from pins 41 and 43 to ground from the 6260, but curious if there is a similar cap to C961/C142 in the Supergrafx.


It looks like it might be C107 as it sits directly above the 6260 and is also a 10uF cap.

Thoughts?

[thesteve]

the 6260 does require a filter cap for each output circuit, so it must
couldnt tell you what cap without one in front of me

[Ravij]

Another quick question - where is the best place to tap 5 volts to power my NJM based amp? I'm going to stick the amp PCB over the HU card slot, as there is plenty of space there, and no heat sources.

Since you'll be sticking it over the HuCard slot, pin 38 on the slot would be an ideal place to grab 5V.

Thought I'd post a pic of the completed RGB mod:

PC Engine DUO with RGB Mod by ravij1, on Flickr

[ApolloBoy]

Holy shit those are some thick wires.

[Ravij]

Holy shit those are some thick wires.

Used an old VGA monitor lead, the RGB leads are individually shielded. Overkill I'm sure