EPROM speed - does it matter?

[BenF]

I think I read somewhere that EPROM chips used should be rated at 120ns or faster.  Was curious if that was a "hard and fast" rule, and/or if anyone has successfully used chips rated at a slower speed.   I have a handful of 150ns and 200ns chips (512k) and wondering if it's worth the effort to try.

[stayouttadabunker]

These chips you mentioned would be perfect.
They're fast enough really...
Are they electronically erasable or do they need to be erased by a UV light?
The ones that are erasable by UV light will have glass window on top of the device (eprom).

[BenF]

Excellent, thanks.  They are UV eraseable.

[jay]

I think we need to qualify this a bit more.

The 150ns are ok for S+ and PE+
If you use the 16mhz board on the S+ you need the 120ns or better.
On the S2000 you need 100ns for the S+ reel proms.

Speaking of which I just noticed the 27c512s are not as cheap as they were AND are not well stocked.
Anyone have any suggestions ?? what is the equivelent of the EEProm so I don't need my UV eraser.

[rickhunter]

You can use 27SF512's, these are flash nand based but I believe they are no longer manufactured.  You can still find them on e-bay as they are used for souping up the program on the car's computer to squeeze that last bit of performance out of some cars.

[BenF]

I'm a GM noob... is S+ and PE+ a style of board within the game, or a style of GM itself?   Mine is a 7200 model, slim style cabinet, not sure what to look for on the main board to tell what that might be if there's different versions/styles. 

If you use a slower chip in a game where you shouldn't... does it simply not work or are there strange effects or artifacts that pop up?  Or can it damage the board itself?

I got 15 27C010, and 25 27C512 for $10 each on ebay.  Not as cheap as they used to be but not too bad.  The 010 chips are all 120ns but the 512's ranged from 150-200ns.  Clean for the most part but not packed the greatest and some of the legs are munged up, think I can salvage them all though.

[idesign]

Back to the original question since it was GameMaker, you can user the 150 and 200ns with the GM.

[ricker]

BenF,

I remember on the old site, it was mentioned that game speed and/or sounds are delayed(like the flipping of the cards), but that most all speeds will work. You may keep an eye out for 27C020 and 27C040 to back up your graphics and mains.

Richard

[StatFreak]

I'm using 200ns chips in my GameMaker and idesign and ricker are correct: the only difference is a slight delay in some of the screen refreshes. 200ns chips are also fine in a 10MHz S+.