U6 was originally a 2716/9316 type ROM (half the memory capacity of a 2732). Did you double the ROM file to effectively program both halves of the 2732 with the same code?

Which U6 ROM file from that archive are you using?

BTW, what problems are you having? you didn't specify.

Yep, "720-3532.U6" is the right file. I don't get any errors from the downloaded zip file.

Try the one on IPDB.
https://www.ipdb.org/files/2737/Bally_1980_Viking_ROMs.zip

Load the "720-35_6.716" file in the upper half of the 2732 buffer or just double it to fill the whole 2732 ROM space.

Your 2732 might be bad.

Is it failing at the same address with every chip?
If you're using MS Windows, open a command prompt.
Go to the folder that has your U6 ROM downloaded from IPDB and type:
copy "720-35_6.716" /b + "720-35_6.716" /b "720-35_6.732"

"720-35_6.732" will be your doubled up file (lower half and upper half will contain the same ROM data).

Or just use the GQ-4X programmer software to load the "720-35_6.716" file at buffer address 0x000, and also at buffer address 0x800

BTW, have you tried to program the chip a second or third time *without* erasing it between programs?

Sorry, I don't have a GQ-4X programmer so can't tell you exactly how, but a standard feature with EPROM programmers is that when you load a file there's an option to tell it where in the RAM buffer you want to load it.
The RAM buffer for a 2732 will be 0x1000 hex bytes long. The "720-35_6.716" ROM file is half that size so loading it at offset 0x000 and 0x800 (these are hex number offsets), will effectively program both halves of a 2732 with that half length file.

Having said all that, I don't believe this is your problem. If your programmer is failing to program the chips, that's another matter.
What brand/model of 2732 chips are you using? And are you matching the type exactly in the software?

if gq-4x gives you a write error the issue is not with the file. The burner is just not able to flip the bits on that chip for some reason. The chip could be defective or you are using the wrong programming voltage / eprom type profile.

What does the marking on your chip say and what profile in GQ4X software are you picking?

Are you using a powered USB hub or an AC adapter wall wart with the GQ-4X? For the 25v burning chips like many 2732 it has to kick up 5v to 25v to write the chip. When on a weenie USB port there is not enough current and the programming voltage doesnt get high enough and the burn fails. (write error).

Your programmer is having trouble programming your 2732 chips. Doubling the ROM isn't going to fix it - this mixup came from us both posting above at the same time before I saw the error you were getting.

Try programming the 2732 file you have multiple times without erasing between programs to see if you can get that bit to program properly.
Also, what brand/model of 2732 chips are you using?

It appears there may be three different types of NEC D2732 EPROMS each having different programming voltages: 12.7V, 21V and 25V
What programming voltage is the software using for the chip you select?
Do your 2732 chips indicate the programming voltage? Post a picture of the EPROMs if you can.

I installed the GQ-4X4 software and there's no 2732 devices listed under NEC.

From the NEC programming voltages listed at:
http://proshivka.com.ru/listprom.php

D2732 25V
D2732A 21V
D2732B 12.5V
D2732D comes up as 25V in my programmer software but it's been known to be wrong

Try programming from the lowest voltage (to minimise potentially damaging the chip) and go up if the program fails. So from the (All Generic) EPROM device selection in the GQ-4X4 software, try "2732B(12.7V VPP)" if it fails, then try 2732A(21V VPP) and lastly 2732(25V VPP).

If it D2732 plain, no letter suffix, its a 25v chip. If you not using a powered usb hub or a wall wart into the gq4x, try that.

Also do they blank check OK? If they are not blank you need to bake them in the UV light before burning or you will get a write error.

I use the generic profiles for 2732. If your chip has no letter after 2732 it is 25v. If it is a 2732A it is 21v. If it is 2732B it is 12.5v.

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