Help with white PC Engine rgb mod

[GAMESMONKEY]

Hi

have just done a RGB mod for a white pc engine with a scart cable, the mod works great nice steady picture and the sound is good, but the colours are very dark.
I know this has something to do with caps to brighten the picture but don't know which ones?

Thanks in advance for any help you can offer  

[davidleeroth]

You need to add an amplifier to the lines as featured here.

Check out the Games Division thread too, where Lawrence just performed the same mod.

[Moosmann]

The Gamesx-Amplifier is junk (sorry Lawrence).

Here is a good amplifier:

http://markus.brandel.bei.t-online.de/PCE-...olorbooster.bmp

Schematic:

http://markus.brandel.bei.t-online.de/PCE-...Verdrahtung.bmp

black wire= 5V
brown wire= ground
and so on....

Bye Markus

[NFG]

I was just about to say it's junk, I know it to be true.  I didn't design it, as you may have noticed.  

Your links didn't show a schematic, so here's the one I use to amazing effect.  Here's a picture of the completed amp.

Here's a link to the thread Mr. Leeroth mentioned.

[davidleeroth]

Hmm.. Maybe I should change the amp. Does it matter a great deal what transistor you use (other than a NPN one of course)? BC33-type Moosmann had should work well?

[Aidan]

Yeah, the GamesX one is junk - the circuit is too simplistic. There's nothing to bring the transistors out of their non-linear region, and it's DC coupled. There's also no protection against short circuits on the output lines!

The link to the schematic that Lawrence provided is pretty good. The transistor used shouldn't matter too much as long as it's small signal NPN.

[D-Lite]

Yeah, the GamesX one is junk - the circuit is too simplistic. There's nothing to bring the transistors out of their non-linear region, and it's DC coupled. There's also no protection against short circuits on the output lines!

The link to the schematic that Lawrence provided is pretty good. The transistor used shouldn't matter too much as long as it's small signal NPN.

Could you just use the BC547 NPN transistor Lawrence used in that other amp?

[Moosmann]

>I was just about to say it's junk, I know it to be true. I didn't design it, as you >may have noticed.

OK :-)

>Your links didn't show a schematic, so here's the one I use to amazing effect. >Here's a picture of the completed amp.

The only one asks, which transistor type used in this circuit ?

The simply BC 33725 ist very good (PCE), but it`s not the best for a RGB Famicom.

Bye Markus