Can anyone improve the rgb output on my duo?

[Ravij]

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

Just swapped the C961 10uf SMD cap for a 100 uf SMD cap. Jailbars I was seeing on PC Genjin 2 in the  blue areas of the sky have gone.

Thanks Steve!

I would recommend  everyone to try this first, as it's so easy to swap.

[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.

[ApolloBoy]

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.

[incrediblehark]

Ravij you were using the same test game as me I still need to get back in my Duo and see if I can finish cleaning up the picture, maybe tomorrow

[gtsamour]

I've done the RGB mod on two TG-16 (US models), a Core II, a Super Grafx and last week on a PCEngine DUO. Ι used the same amp on all of them (made them myself according to the schemtics of the good amplifier http://www.pcenginefx.com/forums/index.php?topic=9299.0) and all capacitors were replaced with fresh ones on all of them (total recap). I also own a DUO-R that was bought already modded for RGB.

The DUO has by far the worst jailbars problem of all...
I noticed that if I use the non amplified sync signal tapped from the chip instead of amplifying it too, the bars are less obvious (i'm reffering to the DUO only)... I'm using bikuriman world as a test cartridge, the bars are very obvious on the blue sky at the begining of the game.

[gtsamour]

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

When you say "220uf aluminum" do you mean electrolytic 220uF capacitor?
What voltage should someone get for the 100uF tantalum capacitor?

[incrediblehark]

you should be able to use a 16v, but I don't think higher voltages make a difference if you can only find ones rated higher

[thesteve]

i used 100uf 16V tant
the circuit is about 4V

[gtsamour]

Do the tantalum caps have polarity like the electrolytic ones? From pictures on google i see they have a stripe, probably the positive pole?

[thesteve]

correct the stripe is positive on tantalum.

[gtsamour]

Will these suffice? http://www.ebay.co.uk/itm/100UF-16V-SURFACE-MOUNT-TANTALUM-CAPACITORS-x10-blb173-/400267121772?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d31c7946c

[thesteve]

thats what i use

[gtsamour]

Thank you... I went to a local store but they only had the non electrolytic tantalum type (without polarity) so I'll get some from ebay.

[gtsamour]

I replaced the C961 electrolytic SMD capacitor (up side of the board, below the card slot and to the right) with a tantalum 100uF but I saw absolutely no improvement, not the slightest...

[thesteve]

then you may have a different issue