EPROM Programming Question

Yes.

Unless they are new, in which case they were probably erased before you recieved them.
Or if they are flash (e.g. 29F0x0) or OTP (one-time program) EPROMs.

There are exceptions, tho it's mostly academic... in reality it's almost never a useful exception. If the only changes you're making is to change bits from 1 to 0, you don't need to erase. The programmer can only change bits from 1 to 0. The UV erasing process sets them all to 1, ready for the programmer to do its thing.
 
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and you need the correct wavelength. i have tried normal uv black light bulbs for really long times without any luck. but lucky enough the erasers are kinda cheap if you are erasing a lot.
 
and you need the correct wavelength. i have tried normal uv black light bulbs for really long times without any luck. but lucky enough the erasers are kinda cheap if you are erasing a lot.

Yes. It's the "germacidal" flourescent bulb type that has the correct wavelength.
 
Programming only changes bits from 1 to 0 .. so you need the erase step to reset all bits back to 1. You can run a 'blank check' first and skip the erasing if all bits are already 1; otherwise you will almost certainly need an erase.

If you're curious, read up on the way EPROMs store charge and it will make more sense.

LeChuck
 
you can check it to the program data to see if the IC data matches the data on the computer.
 
I would pull the part again and verify that the contents match the image file you tried to program. If that checks out, I would verify the connections between the board and the legs of the chip (in case you accidentally broke a leg or solder joint in the process of removing/reinstalling).

LeChuck
 
Most programmers do a blank check before programming anyways. Perhaps yours did not (does not) ?
 
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