Recently I bought a "Castlevania" for NES. Since I bought it from Ebay, I decided to get NTSC version (mostly because of lower shipping costs). My console supports PAL format, yet after few "adjustments" it can run NTSC games as well. And here's my problem:
Game arived, but I noticed animation errors. During atacks, character "blinks" (disapears and apears).
Yet this is not major problem. Major problem is status bar (whole stuff that is on the top of screen: health bar, used item, points etc.). When I move forward and screen "scrolls" to another location, bar stays at its place. So, after beginning of level, if I proceed, I leave whole "status" behind. It's not like I can't play because of it, but it's rather annoying.
Here's the question: is there something wrong with cartridge, or is it natural outcome of using NTSC games on PAL console? Even though it's modified to run both formats.
I had also problem with Castlevania 2 (UK version) - when I wanted to type password, I realised that instead of letters and numbers, I have just some of the letters and symbols (hearts, etc) instead of missing letters.
I have no idea what caused this. It's kinda hard to believe that both cartridges are faulty.
Have someone encountered similliar problem, or have any idea what's going on?

I dont have a PAL system, but I tried the NTSC Rom in an emulator that was running in PAL mode and I saw the same as you, so it is not a physical problem, just the way the game was written.

A fixed status bar is written by making use of something called Sprite 0.    Basically the game programmer resets their scrolling attributes to 0,0 when displaying the status bar, then waits for a special sprite (the one at sprite index 0) to be rendered, and then at that time the game scroll values are immediately written to the scroll registers.

PAL and NTSC have very different durations for Vblank and screen draw, so it is possible that the programmers have a glitch in that they are not properly detected if/when to reset the scroll values.

No idea about the flickering.

Al

Al

Thanks for info. Looks like I'll have to get myself another console then.