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Problem writing to M27C4001 with Epp-3 ?


Graeme Hinchliffe

Jan 1, 1970
Sorry for the cross post, I am unsure which group to post this question

I have recently bought myself an EPP-3 USB eprom programmer for some
hobby work. Unit seems sound enough and I have successfuly written to
M27C1001, 27C040, and M27C801 devices. However I also won a batch of
M27C4001 devices on ebay. If I try to write to these the process works
for a breif period and stops with a failure, even if I try to write back a
blank image to the device. When I have written partial data to a device
if I read it back in, the data seems to stop at $30000 on each of the

Is this a bug with the EPP-3 unit/software? I have tried specifying the
device as 27C040 which gives the same behaviour. Also erasing the devices
and then trying to use them has no different effect.

I am hopping there is some obvious solution to this as 12 27C4001 for £24
seemed like a good deal (all unused).

Thanks in advance