Why do my rom burners hate 2764 roms?

QuartrArcade

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Been burning roms for years now and it seems like I've had horrible luck burning 2764 eproms. I usually use roms pulled from junk boards that I've erased for burning.

I'm using a Galep-4 programmer and picked up a Batronix USB programmer as well. Both running on an older PC using Windows XP (I think).

In both cases, seems like 75% of the time the roms just don't burn right. I don't have nearly as many issues burning 2532, 2716, 2732, 27256, pretty much any other roms.

Any thoughts? Both burners have a wall outlet power adapter for power.

Thanks,
Anthony
 
If the problem is happening on two different burners, it can only be

1- Bad bunch of eproms (... or over-exposed to UV erasure ? )

2- You're choosing the wrong device type (12.5V, 21V, 25V ? Intelligent Vs. Quick Programming ? )

What kind of eproms are they ?


Steph
 
I think you've just seen a bad batch of Eproms. I've burned
thousands of 2764s over the years (many for my Vectrex games)
and there was a time when I had a lot of problems programming
2764A's. I thought it was a programmer problem but the problem
went away after a few months and a new batch of Eproms.

I'm still using my old but reliable Needhams PB10.

JD
 
I've had this problem for quite a while in varying degrees, so I doubt it is the roms (although maybe that is part of it) as they are from a bunch of different pulls. The vary from manufacturers, including, Intel, TI, Fujitsu, Amtel, etc.

I usually erase them for about 10-15 minutes.

My burners allow you to specify the EPROM for most manufacturers. The Batronix gets very detailed in that and I was still having problems.

Yesterday I my burn rate was about 30%, of course I just tried some MBM2764s this morning and all five burned fine. I'll pay more attention to the manufacturer and erase times in the next few weeks.

I definitely avoid the Mitsubishi M5L2764s I never had any luck burning those.

Thanks for the input, just wanted to make sure it wasn't something real obvious.

Anthony
 
I am not familiar with either of those two burners, but if they are relatively new ones, they probably are based on the open source Willem hardware. If so, you need to supply them with a high amperage wall wart. The usual 500mA ones will not work. I used a 1.2A 12V power supply from a laptop before I was able to get the old NMOS EPROMs to burn.

This has been discussed to death on a number of the hardware boards. The newer eprom burners use a DC to DC converter to jump the voltage up to the 20+ volts required by the older NMOS chips. This works OK, but the USB connection is current limited and the voltage will begin to drop off during the burn process. The only way to prevent this is to start with a beefy external power source.

If you have a laptop power brick (I used an HP one, it had the right power connector) give it a try as your external power souce.

ken
 
i erase them for 3-4 mins and they clear out fine for me in that time. is it normal for 15mins?
 
I think you've just seen a bad batch of Eproms. I've burned
thousands of 2764s over the years (many for my Vectrex games)
and there was a time when I had a lot of problems programming
2764A's. I thought it was a programmer problem but the problem
went away after a few months and a new batch of Eproms.

I'm still using my old but reliable Needhams PB10.

JD

+1 I like mine so much so I bought a spare and this one came with some adapters. This is my new spare Needhams PB10 and I can't say enough about them.

http://www.ebay.com/itm/110943833044?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

As for the Eprom problem; I usually read them several times before I try to erase them. Most times a bad eprom will give different crc checksums each time they are read and they are almost always bad. No amount of time in the eraser will change that.
 
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That was a great deal! I still use my PB-10 for most things. Don't have any adapters for it.... Did you end up with any spare adapters?

I will let you know as soon as it gets here. I just got it paid for on Tuesday as Monday was a holliday. I just happend to do a search for one for another member here and seen that on a buy it now.
 
I have never had any problems burning 2764, or anthing for that matter with my willem GQ-4X. I also had a pocket programmer 3 that suddenly stopped liking the 2764's out of the blue. It may have been a software update but I cant remember now. It was not bad chips as the willem programmed the same chips fine.
 
Dunno... My eeTools programmers just work... <knocks on wood>

You get what you pay for.

Now with that said, i will say that there are some ROMs that are in the different software programs for various burners (TOP2004, TOP2084, etc. from China, and others) that will have the wrong voltage for chips from time to time. If you use voltage that is too high you will fry the chip. Too low and it won't program.

Go to http://datasheetarchive.com and download THE datasheet for the exact ROM you are having troubles with and check to see if the programming voltage is correct.

Also, when I put the EPROMs in the socket, I close the socket and slide them left/right a bit to make sure there are good connections being made to the pins. Normal sockets clamp on the wide parts of the pins while zero force sockets in the programmers clamp on the narrow sides of the pins. Those can have corrosion that hasn't been cleaned off yet.

RJ
 
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