Faulty NEC D27C1014D-15 ?

auberwn · Apr 23, 2017

I purchased a few NEC D27C1014D-15 to burn the unibios and the diagnostic bios and the first time a few failed to program. Now that I've got an eraser I've concluded that two of them just fail to write after the 000538 address.
Has anyone got any experience with this? Can it be something other than bad chips?
The other four I've got seem to be fine.

skate323k137 · Apr 23, 2017

With older EPROMs you can pretty much expect a decent percentage of defective chips.

werejag · Apr 23, 2017

when i was making ghostlops out of 20 eproms 1 or 2 would not take the binary properly. some of the uv eproms i had to hit with tons of uv and they would finally work.

mainman · Apr 23, 2017

I am not familiar with the chip your using and its compatibility. The 27c1024 and 27c210 are what is commonly used.

Like what was already stated some eproms are defective and have stuck bits, sometimes cooking it longer will solve the problem.

btw clean the window with a pencil eraser

shadows · Apr 23, 2017

Could be a number of things.
Bad contact between the pins and the socket due to corrosion on the pins. If your programmer doesnt do an insertion test it can waste you a lot of time.
Improper power to the programmer.
Not enough time spent in the uv eraser.

werejag · Apr 23, 2017

cleaning the pins also helped yes

auberwn · Apr 24, 2017

Thanks to all. I'll try all of your suggestions. It just seem weird that both fail at the 0538-0540 address.
I'm using the cheap TL866

Faulty NEC D27C1014D-15 ?

auberwn

n00b

skate323k137

Professional College Dropout

werejag

Galford's Poppy Trainer

mainman

CPS2 Person.,

shadows

Mature's Make-up Artist

werejag

Galford's Poppy Trainer

auberwn

n00b