Recomended length to erase eprom chips

I just got my Hong Kong el-cheap-o eprom eraser in the mail today, and it didn't come with any sort of print material. What is the optimal time to erase 27c1024 eprom chips? I have a batch erasing right now for 60 minutes. Can I damage the chips if I erase them too long?

Thanks,
Bill

I have a pretty decent eraser and I usually leave most any chips in there for 15-20 minutes and they are good 2 go.

Ive read that it depends on the strength of the light and the type of chips.

They should still be alive after an hour.

I left some chips in the eraser and the timer stuck when I took a nap. It appears a few of them were totally fried after a couple hours.

They smell funky even after 20 minutes.

The time depends on the light strength and the chip type/mfg... Anywhere from 20 to 45 minutes.

Yes, too long will fry them.

Your best bet if it is unknown would be to try for 20 minutes and then do several blank tests with your EPROM programmer. If one of the blank tests fails then put it in for another 10 to 20 minutes.

Raymond

The average/optimum erasure time seems to be around 15 mins.

Im using a small water purifier UV lamp, it takes 10 - 15 mins.

60 mins your wasting time and electricity.

Yeah with my el-cheap-o eraser, I can successfully erase 5x 27cXXXX chips at a time in 20 minutes. Doing 15 minutes leaves tiny amounts of data on the chips, the extra 5 minutes gets them nice and clean.

Thanks for the help guys

-Bill