The TV is a Brandt 55170 RH, its chassis is a Thomson TX807.
21 inches SECAM TV (can take both 50 and 60Hz syncs)
240p test suite on a Megadrive at 60Hz, RGB through Scart.
320x224
256x224
That’s with the screen calibrated to show the correct geometry. Because I can’t calibrate the horizontal amplitude on this TV, it means it leaves parts of the active area outside of it and hides important information on some machines (notably the CGA computer). So I set the screen with a little less vertical amplitude to get everything to show for a slightly crushed, but frankly not noticeable, picture.
320x224, then 256x224.
The upper left corner is a bit lower than the rest. It has been like that for years, I’ve never noticed before using patterns to calibrate the screen. I don’t know how to fix it, sadly.