I'm trying to replace 2 EPROMs (M27V322 and M27V160) in an old machine. I've got a dumps of the original chips and the data writes but the unused bits stay at FF.
The problem is the system does a checksum and sees the unused as FF instead of 00 (as in the original chips) and the checksum fails so the device will not boot.
Is there a way of writing those unused as 00 instead of them being left as FF?
Is it as simple as me missing a setting in the programmer?
I'm trying to replace 2 EPROMs (M27V322 and M27V160) in an old machine. I've got a dumps of the original chips and the data writes but the unused bits stay at FF.
The problem is the system does a checksum and sees the unused as FF instead of 00 (as in the original chips) and the checksum fails so the device will not boot.
Is there a way of writing those unused as 00 instead of them being left as FF?
Is it as simple as me missing a setting in the programmer?
Michael.
Yes you simply need to use "Fill Buffer Hex" in the edit menu.
Can I delete my thread? This issue has been resolved.
No, please don't delete and explain how you resolved. It could help other members of the community.
It was resolved because I didn't realise that the adaptor for my GQ-4X had to be modified running 3 wires for addresses A19 to A21 from the main unit board to the adaptor board for M27V32 and M27V160 chips.
Can I delete my thread? This issue has been resolved.
No, please don't delete and explain how you resolved. It could help other members of the community.
It was resolved because I didn't realise that the adaptor for my GQ-4X had to be modified running 3 wires for addresses A19 to A21 from the main unit board to the adaptor board for M27V32 and M27V160 chips.
With the GQ-4X if you have the right adapter and the 4 pins have not been cut you do not need the jumper wires. It works via the ZIF.
Unused bits left as 00
Posted - 11/13/2017 : 12:26:19
