Probably need to double check the jumpers if you are using a larger EPROM. I am not familiar with DM if it has jumpers or what.

Also sometimes I heard you can sometimes use a larger EPROM if you "double up" the code. What it means is that you make a binary copy of the orignal EPROM before burning. So if you had a 512k code and 1mb eprom, you copy the code 2 times into one file. In DOS you use "copy fn+fn2" or something. I think this will only work though if the bigger chip is pin compatable with the smaller chip. So, the game is fooled into thinking it has the smaller chip in place and reads the code correctly. I haven't yet done this, only read about it.

I never really have much luck using EPROMs that are different then the original size, why not copy over the EPROM thats in there?

Do this but back it up first. Always use the correct size chip for the code, less headaches that way...

If you're trying to load Jim's Demolition Time, then the jumper settings on the WPC are fine as it. The original is a 4MB and DT uses 8MB. No changes required for that.

I'm not sure what the cause of your issue is however. I'm not familiar with your programmer. Does the checksum match expected value after programming? Did you try and do a verify after programming?

FYI, I am running it and not having any issues.

Jaz

I've had similar issues and I think it was because the chip didn't erase all the way. Maybe I have a lousy UV eraser but it takes a long time. Does your software have an blank check? Also triple check the legs after you install it. It's very easy for one leg to pop out and sometimes tough to see.

You may also want to hook your programmer up to an external power source if its not already. Also you can try a double writing the chip if you don't have an external power supply.

viperrwk

If you use a larger eprom:

1. Ensure the pinout is the same. Often they're quite different especially in the 25xx vs 27xx vs TMS27xx series and require an adaptor. In fact any use of a larger one may likely require one to ensure it does something with the additional address pins even if the pinout is the same and the socket could handle the extra pins -- but they may not be connected -- see below.

2. Double (or quad, as appropriate) up your code is safest, but you should also tie any of the additional address lines high or low -- don't leave it floating as you could end up getting 'dirty' reads out of the alternate "bank" of code (why you double up code anyway) Tie-ing means connect the address pin directly to GND or VCC (+5V)

The advantage of using larger proms is you can then do bank-switching to quickly switch between two (4, 8...) rom versions. Like a home rom and arcade rom rev. Tie a DPDT switch(es) to the address lines and have the center lead go to the line, and then one end to GND and the other end to VCC. Then, with the game off, just flip the switch to select the alternate rom. This assumes you burn rom 1 into the 'low' bank, and then rom 2 into the 'high' bank.

Hi,

I use the G540 USB Eprom Burner too, but this Burner is a lot of crap !!

I have always Problems, to burn some Types of Eproms,
especially the "old" N-MOS, like 2716, 2732 and 2764.
they use a Programming-Voltage of 21 V - 25 V and
it is not possible to burn this Type Eproms correctly.

I recommend: don't buy this piece of shit.

Most USB burners are crap because they can't provide enough amperage at the elevated voltage levels required by old chips. They try to up the 5V/500ma maximum power provided by a USB port up to 21-25V and simple power logic shows that fixed available amperage must go down when volts go up and it's not enough to make the chip take the programming.

Sometimes you can use an external power brick and a VERY short USB cable to help, but I've seen the same results on some USB programmers.

I have both an old Data I/O and G540 programmers. I use the latter almost all the time with an external power brick on an old windows XP laptop on a USB port designed to power an external CD drive. Have had no issues with the G540 burning/reburning 2532/2716/2732s as well as newer chips. I always hook it to external power to burn.

viperrwk