Amiga 500 Rev 5. and ECS chip set...??

[Zac67]

Really? Which one?

Also doubting that one - Denise actually has nothing to do with either CPU or Copper instructions, it's more of a rather simple 'bitplanes-to-palette-index-to-digital-color' converter, mixing in the odd sprite here and there. Pretty much like a RAMDAC without the DAC.

Plus:
ECS only upgraded Agnus & Denise. Gary & Buster didn't change (apart from being scaled up for A3k) and Paula never changed at all.
Even AGA upgraded only Agnus/Alice and Denise/Lisa (without pin compatibility).

[Zac67]

Either way, Super Denise is required if you want ECS.

Nope. ECS Agnus alone (2 MB chip) runs fine w/o problems.
For flexible scan rate modes and/or SuperHires you'd need Hires Denise, of course.

[Zac67]

ECS stands for Enhanced Chipset or something yes?  And "ECS" machines from Commodore came with a Super Denise, correct? Now, if you don't want compatibility with the couple of ECS games that use the new graphics chip out there, sure, stick your 2MB Agnus in. That's not ECS, though.  You need a Super Denise or you've got a hybrid.

"ECS" compatibility in games is usually all about having 2 MB chip RAM. Show me a game requiring non-PAL/-NTSC screen modes and/or SuperHires and you've got a point.

[Zac67]

I plugged the ROM in without this modification & must've damaged a chip or something because there's a column of spurious lines in the column whereever the cursor is.

That has nothing to do with anything ROM connected. Sounds like something on the chip bus. Have you checked power levels?

Original C= ROMs came with a simple resistor installed between pins 1 & 31 to rearrange A17. I'm pretty sure nothing breaks if no modifications have been done, the system simply won't boot up.

[Zac67]

An '010 won't cause anything of the sort either. The Hires Denise might be a good lead - ECS modes won't work w/o a newer Agnus anyway. Possibly the 3.1 ROM tries to activate some trickery.