Can anyone improve the rgb output on my duo?

[gtsamour]

Oh it is the jailbar issue allright... I have it on all my PCE type consoles. Its just that on the DUO it is more intense.

Just a question.... does the Sync signal (that Im getting straight from the chip) need amplification or not? Because right now I am amplifying it... I'm using the good amplifier that I made myself using the popular schematics http://www.pcenginefx.com/forums/index.php?topic=9299.0. I also used it on a bunch of other PCE consoles with good results but its the first time (the DUO) im using it taking all signals from the chip, i took the signals from the expansion port on all the others...

[gtsamour]

No reply?

[Frank_fjs]

I don't 'think' that it needs amplifying, and I don't think this would cause jailbars either way. I'm not 100% sure though as I've never used the amp that you're using, I've always been fine with the 3 x transistor method.

[gtsamour]

Well the schematics also include an amplifier for the Sync (just sync and not composite sync) thats why I asked. I tried with and without sync amplification and the difference that I could notice was that WITH Sync amplification the colors were more "normal" and without the colors were more intense...
Jailbars were present in both cases in the same intensity but thats not the reason why I'm asking, its the colours Im worried about.

[thesteve]

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.

[gtsamour]

Yes right, I got confused because in many mod schematics on the internet a lot of people show mixed up info. Some get composite (which i know does not need amlification) and indicate it as composite sync (which obviously does).

Could a weak sync signal cause incorrect colours or is it just my imagination?

As I said before, the 100uF tantalum cap did nothing for me that I could see. Maybe because my DUO is totally recapped recently and a difference is seen with old caps boards? Who knows...
I also have replaced the 7805 power regulator with a fresh one.

[thesteve]

a weak sync can cause color issues with composite.
PCE RGB does not match the colors PCE composite uses, due to the component blending not being even in the system stock

[gtsamour]

I would like to ask your opinion about the most popular amp at this time I believe... http://imageshack.us/f/13/pcergb.jpg/

Is it a good amp from a technical point of view or is it flawed? Does it draw a lot of current or it's power consumption is negligible?
Well the results it produces according to my experience are excellent but just out of curiosity...
Im asking because on another forum someone was presenting this amp as an amateur cirquit drawing more power than the Hucard itself... ofcourse he could be just another a-hole...

[Frank_fjs]

I'd like to know the answer to the above questions as well.

Would also like to know what the experts thought about the simpler 3 x transistor 1 x resistor method, as shown on mmmonkey.

http://www.mmmonkey.co.uk/console/pce/amp.htm

[thesteve]

that mmmonkey amp is seriously flawed, but closer to ideal in 1 way
the amp gtsamour showed is a good amp, just could be better

[Frank_fjs]

How is the mmmonkey amp flawed Steve? I ask as I know of a lot of people using it (built into the SCART plug) and have never heard of any problems.

Also, Steve, don't you have a pre-made PCB amp available for sale, or is it bluebmw I'm thinking of? Either way, is a pre-made amp available from somewhere? I swear I recall reading something about it and seeing some pics of a prototype, just not sure if it ever eventuated into anything.

More importantly, what do you guys use for an amp?

[gtsamour]

that mmmonkey amp is seriously flawed, but closer to ideal in 1 way
the amp gtsamour showed is a good amp, just could be better

There was this hypochondriac guy on another forum going crazy saying that its not a good amp, it doesn't have termination, it doesn't output the correct currents, it has high power consumption etc so it got me thinking.... is it true its not a good amp or is he stupid or something?
And if its not a good amp how could it have been published in a japanese book in 1988 and how come so many people still use it...

[Drakon]

the pc engine 1988 2sc1815 amp is a simple amp I certainly wouldn't call it a good amp.  I've had issues with that amp in the past where other amps were fine.

[gtsamour]

What kind of issues did you have?
Speaking for myself, I used this amp on 6 different (different kinds) PCEngines already and I got perfect results evereytime on more than one tv sets.

[thesteve]

the mmmonkey amp needs coupling caps on the outputs or voltage offsets on the inputs.

the 1988 amp is a basic video amp (not flawed in its basic design) it could just be mode more specific for the PCE signals.