RGB amp

[fraggore]

no should be fine just swop the comp sync on pin 20 to comp video.
use line A pin 22 on the port as the diagram here.

http://www.gamesx.com/misctech/pcebp.php

[fraggore]

by the look for it your using pin A 22 if so try C 22 that sync comp sync.

[Duo_R]

The 2nd link to the gamesx rgb amp is a better design but also a little dated. I had luck using the design that uses NJM chips. I can link you later or search for it on gamesx. Same one used for N64 with slight modification for PC Engine.

I followed the guide roughly (result here: http://www.bordersdown.net/showthread.php/115219) and the picture on my LCD TV isn't that solid unfortunately. Looks great on my Commodore 1081 though.

Any links or guides for improving the amp? Thanks. 

EDIT: Would the design in the diagram on this page be a good bet? http://www.gamesx.com/rgbadd/duorgb.php

[speedlolita]

Also, is B1 worth grounding or not?

[fraggore]

the only ground i used was pin a 21 and put that on the scart in 4 so you sould be ok.

[speedlolita]

I see, I used 4, 18 and 21 as per mmmonkey guide - doesn't seem to make a huge difference, but whatever. Colour seems very washed out unfortunately. On the 1080p Sony and an old CRT at least. Looks relatively fine on my Commodore monitor (not as good as C-Sync unfortunately) and my Sharp LCD - although the Sharp has image smear which isn't present on the Sony. Irk.

The 2nd link to the gamesx rgb amp is a better design but also a little dated. I had luck using the design that uses NJM chips. I can link you later or search for it on gamesx. Same one used for N64 with slight modification for PC Engine.

Would be much appreciated.

[fraggore]

odd mine displays really nice on my samsung tv and my tft with a upscaller and i am using the comp video to pin 20.

did you use a 75r resistor inked on pins 8 and 16 of the scart lead plus the 5v from the transistors collectors has to be put to pin 8 switching voltage as well

one other thing make shore you have the red,green.and blue wired correct on the scart lead i wired red and blue wrong once was thinking the colours look a bit odd then i realised lol.

[speedlolita]

Yes my colours are correct, it's just the awful scaler in the Sony I believe. Horrible television. I haven't used the resistor no, maybe that might help things. I'll just have to identify one in my packets of resistors that I have. Irk!

EDIT: Adding a resistor doesn't seem to have done anything.   It autoswitched before I guess, thought it might have lowered voltage to level where the TV would detect it at 4:3..

[fraggore]

This may help pic of the pins i used
on the transistors i bent and soldered all of the collectors together then soldered the emiters to pins 15,11,and 7 then soldered the RGB to each base as mmmonkeys guide.
http://www.mmmonkey.co.uk/console/pce/amp.htm
Then put 5v on the collectors i tock that from the av port.
Then i ran a small wire from the collector to pin 8.
Then soldered a 75r resistor one end onto pin 8 the other onto pin 16.
Tock ground from the av port and soldered that to pin 4.
Added sound left and right to pins 2 and 6.
Then used composite video to pin 20 you could use composite sync but video worked fine for me.



also as thesteve was saying you could add 3 4.7K resistors and 3 22uf cap before the base of all 3 transistors.

I ain't no expert but hope this helps.

[speedlolita]

I think I'll be adding the resistors and caps when I build a new SCART adaptor thing with a new PCB. For now I'm content at least. Completely playable on my Sharp TV - which is my main.

Thanks a lot for suggesting composite video for sync.

[fraggore]

no probs mate

[thesteve]

heres one i just did

the 2 transistor circuit is a sync amp

[fraggore]

interesting have been looking for  good amp you got some values for the components.

i also have this amp i was thinking of making.

[speedlolita]

And how does that need to be modified to work on the PCE?

[thesteve]

that will work on PCE as it sits.
i installed in in a TG16 cd dock.