Could someone burn me new NAOMI BIOS EPROMS?

[undamned]

I've got two BIOS EPROMS from working NAOMI systems that I tried erasing via a proper UV box and for some reason when I try and burn the image to them my program says they are not fully erased. I've tried this multiple times and for extended time periods (much longer than typical UV erasures I've done in the past. I've made sure the UV window is super clean and free of spots or any marks) and no joy.

Would somebody w/ experience in this give this a shot for me?

I can just send you my two EPROMS and a few bucks for your trouble.

THANKS!
-ud

[ED-057]

If you keep trying to erase 'em and they don't erase, it may be that the chips are dead. Have a look at the contents of the chips and see if they are partly erased now (most bits being set) or if they are unchanged.

What type of EPROMs are they? Maybe you can replace them with EEPROMs and not have to bother with a UV eraser.

[rtw]

Says they are not fully erased. I've tried this multiple times and for extended time periods (much longer than typical UV erasures I've done in the past. I've made sure the UV window is super clean and free of spots or any marks) and no joy.

Would somebody w/ experience in this give this a shot for me?

I can just send you my two EPROMS and a few bucks for your trouble.
-ud

Dump the EPROM's if they are full of FF's they are erased if not you
need to get a new UV eraser. These 27C160's are pretty new so they
should not fail. What kind of EPROM programmer are you using ?

rtw

[undamned]

As I recall, both chips I tried erasing came up with one byte that would not erase (even after multiple erasures). I could try leaving them out in the sun for UV exposure and see if that produces differently. I'm using an EMP20 burner.
-ud

[rtw]

As I recall, both chips I tried erasing came up with one byte that would not erase (even after multiple erasures). I could try leaving them out in the sun for UV exposure and see if that produces differently. I'm using an EMP20 burner.
-ud

Was it the same byte on both chips ? Try the UV eraser for 1Hr and then
dump the chips to see if they are all FF.

rtw

[undamned]

Yeah, it was the same byte on both chips. I'll try and erase them again, tomorrow, for a long period, and then read them.
-ud

[ED-057]

Check the corresponding byte in the image that you intend to program, maybe it's not even necessary for that particular one to have all the bits set.

[rtw]

Yeah, it was the same byte on both chips. I'll try and erase them again, tomorrow, for a long period, and then read them.
-ud

That is very very weird. So before you program it the same byte
contains the same value on both chips ?

rtw