eprom Problem

[crossfire]

I wanted to change out my payout for my IGT S+ so I purchased a new reel eprom.  Made a file backup before I put it in, just in case.  The eprom worked great.  I decided to check my backup and received a 62-1 error.  Put the original back in and cleared. Works Great. What am I doing wrong with my backup file. I have a Willem programmer and I am using the 27c64 chip. All settings are correct. What am I missing.

[knagl]

Have you done a diff of the data you read versus what you burned on the backup chip to ensure that you made a good burn?  Are the checksums the same?  Do you get the same checksum if you try reading your good chip again?

[crossfire]

thanks for the reply, I thought I did but you know how that goes.  I took out the good one and checked against the file and sure enough the very first bit was different.  Cleaned the chip and tried again, boom goes the dynamite.  Works great. I am usually very methodical but sometimes get ahead of myself.  Thanks again.