EPROM burning

[scrappysphinx]

Hi all, i have a Sivava Willem board and am trying to program a 27C4096 rom but having issues.

The chip was programmed with a multibios for the Mega CD 2 but i have a Mega CD 1 so erased it using a UV light. Willem software does a blank check and passes. I have grabbed the mega cd 1 multibios bin file from mmmonkey

Load this up in the willem software and click burn. It gets to about 26% and then comes up with an error. I have now tried erasing and burning 3 times but always comes back with the same error at 26%

I have the programmer connected to the parallel port with USB providing additional power.

I'm not massively familiar with programming chips which is why i went with this cheap programmer. Could it be the willem at fault?

Any tips on what i can do to try and get a successful burn? There is a power connecter on the board, would it be better to provide the board with external power instead of USB and what sort of Voltage/Amps would be recommended.

Thanks

 

[ShambleS1980]

i there enough space on the chip for the data you wan to write to it?
thats the only thing i can think of that would cause it to stop at the same place every time..

 

[scrappysphinx]

Hi buddy, i read the chip to make a backup of the mega cd 2 multibios before erasing and it came out as a 512k file. The file i'm trying to burn to the chip is also a 512k file. As i said though i don't know much about burning so just following mmonkey's guidance

 

[keropi]

that's 99.9% a power issue... just use a 12v psu instead of USB and you'll be OK
use a center=positive psu

 

[johnim]

i would say power too mike

 

[scrappysphinx]

Thanks guys, will try again this evening and report back

 

[Merlin]

Me three - I had a Sivava Willem for a while and it wouldn't burn some chips properly unless it had a beefy 12v PSU attached.

 

[protek]

Me three - I had a Sivava Willem for a while and it wouldn't burn some chips properly unless it had a beefy 12v PSU attached.

I concur.

 

[wmsteele]

I've encountered the same problem when using the PC's usb ports as a power source. Swapped over to a 5v/2a usb plug (Samsung adapter supplied with a Galaxy) and had no further issues.

 

[roy_bates]

yes its a power issue.

to program small eproms its fine over usb as it supplys 500ma at 5 volts.
to do bigger eproms i found you need at least 12 volts at about 2 amp.

 

[scrappysphinx]

So, just tried again using a 12v 3amp power supply for the extra power and get the same error at 26% burning.

Exact Error is

"Error at 0x020006 Chip=0x26 buffer=0x2E"

One more try with a 12v 2a psu provides the same error again at 26%

 

[roy_bates]

does the regulator get hot?


have you got the programmer set correctly?

 

[scrappysphinx]

regulator doesn't appear to get even warm, it remains cool to touch

 

[keropi]

maybe it's a dead eprom, happened to me 3-4 times... do you have another to test?

 

[roy_bates]

have you got the board set correctly as these have the voltages set via jumpers.

 

[scrappysphinx]

The jumpers on the board are set the same as the program shows (changes depending on selected chip).

I only have one other eprom but don't want to erase it. I'll grab some more chips and try again.

 

[keropi]

it's common for older UV eproms to fail like that... or they become too slow after writing/erasing and they don't work well... don't forget that eBay eproms are mostly used and noone knows how many erase cycles they've had...

 

[scrappysphinx]

As suggested it seems it's the EPROM.

The reason for the new burn was when I was installing my first chip I broke two legs off the chip while inserting into the socket. I linked it with wire and it worked for a little while. We'll I just took the original chip out (which now has 4 broken legs) to try reprogramming it, just to check.

A little bit of ghetto repair first on the broken legs, two we're long enough to recreate the legs with small pieces of paper clip, the other two I tacked some wire and soldered them to the underside of the 16 bit adapter. Chip was programmed and verified successfully.

Seems I need a new chip.

Anyone know where I can get a new 27c4096 or are they only available reclaimed?

 

[roy_bates]

i dont know where to get them new,but i would try to get a few at a time like this:

http://www.ebay.co.uk/itm/10-AM27C4...al_Components_Supplies_ET&hash=item5af674f4bd

if any fail after testing them,just ask for replacements.

 

[scrappysphinx]

Hi all, I'm gonna revive this thread a little.

Today I picked up a Neo Geo AES and have removed the bios and fitted a socket in preparation of installing a unibios.

i have a 27c1024 EPROM that I'm trying to burn the unibios v3.1 to (downloaded from the official homepage) but it keeps failing to burn.

i know the chip is good as I've tried burning a mega cd region free bios to it and that works fine however when choosing to burn the unibios it gets to 16% and fails every time. The only difference I can see is the unibios comes in .rom form and my mega cd bios is in .bin

i am using a willem parallel programmer to attempt the burning and have tried using both USB and a 12v 3a psu for power but both fail in the same place.

any advice would be appreciated

*Edit*

All sorted. Rebooted the laptop i use and reset bios settings and chip programmed and verified fine. My new AES is now rocking the free v3.1 Unibios until i can afford a paid for v3.2