Mega Drive 2 THS7374 with jail bars?

[Syntax]

Ive been playing with my ossc and Mega Drive 2 today and noticed something that's confused the crap out of me.

First things first I have bypassed the internal RGB amp and am using a THS7374. Subcarrier RGB and sync all still go to the original amp so composite video still works if needed.

I have played around 10 Megadrive titles with light blue backgrounds and dark sprites, it seems to be the best way to see ghosting,ringing,jailbars ect.
The jail bars are present.

AND

If I load up a SMS game on the everdrive I get 2 or 3 horizontal bands that display jailbars, kind of like the way an oscilloscope screen looks (Castle of illusion is a great example)
Black sprites on light backgrounds leave trails also (California games, halfpipe watch the skateboard)


Will have to borrow my brothers power convertor to test some real SMS games and see if the jail bars are there.

[Syntax]

Today I I removed the original amp from the mix, so the THS7374 has a clean feed for RGBs. Subcarrier resistor removed close to the original amp.
Jail bars are still present.

I should note that the RGB lines that run from the cpu on this model seem to stay well clear of the subcarrier line. Blue does seem to get close to the 7805s though.
Subcarrier line runs from a via directly under the cpu.

[rama]

Can you post some information on your mod? A detailed picture of it and maybe schematics.
It'd help me do the same mod to one of my machines. Thanks

[Kez]

A guy in this thread on Sega-16 claims that model 2 jailbars can be alleviated by upping the capacitance at CE29.

[Hoagtech]

Today I I removed the original amp from the mix, so the THS7374 has a clean feed for RGBs. Subcarrier resistor removed close to the original amp.
Jail bars are still present.

I should note that the RGB lines that run from the cpu on this model seem to stay well clear of the subcarrier line. Blue does seem to get close to the 7805s though.
Subcarrier line runs from a via directly under the cpu.

Are you using the 75ohm resistors after the chip or is it the new L shaped pcb with the resistors built in?

[Lawfer]

Are you using the 75ohm resistors after the chip or is it the new L shaped pcb with the resistors built in?

What does that mean?

Are you asking if he has a resitor inside his scart cable to attenuate the output to 75 Ohm or if his RGB Bypass mod has an in-built attenuation?

[Syntax]

It's not going to be 75 ohm terminations or inlines causing it. Happ3ns with the buffered csync or comp as sync.

Replaced the power supply and transistor but the issue is still present.
May try larger filter cap on the transistor output.

Will also try what you linked @Kez thanks.