[sdiy] EPROM Burning Question

[Tim Curtis]

Hi Everyone -

I'm stuck with what is probably a stupidly simple problem, but 
apparently I'm more of an idiot today than I normally am...

I've got an EPROM burner here on my PC - it's a "Modular Circuit 
Technology MOD-MEP" - that I've been using with no problems whatsoever 
thus far. 

According to the specs it will suport EPROMS up to the 271024.  Up until 
now I've been using it with smaller devices, limited to the 2764 and 
smaller.

This unit has software that runs under DOS and is rather archaic to be 
honest.  It's software has you load a .bin file into a buffer before 
programming the EPROM.  According to both the manual and the software 
options, the buffer is selectable between 64K and 128K - obviously 
smaller than some of the supported devices.

I'm trying to program a couple of 27256's for a software upgrade for my 
K150 and have run into a problem where every time I program an EPROM  I 
get a bad checksum (always the same) and find that there is an error on 
the programmed EPROM at $4000, again always the same - $40 instead of 
$46 as it should be.

I've tried programming the 27264 in two sections ($0000 to $3FFF, $4000 
to $7FFF) and I've tried programming it in it's entirety, both numerous 
times) and I keep coming up with the same problem.  I also encounter the 
same problem programming the second EPROM for the K150 - different hex 
but at the same address of $4000.

Obviously this is the first address of the second 128K.

I admit to being suprised that I can program it in one shot at all, with 
the 128K buffer size.  This isn't exlained at all in the manual,

Does anyone have any ideas or suggestions as to what I'm doing wrong?

Thanks,

Tim