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Mark Leigh
Canada
5 Posts |
 Posted - 02/08/2006 : 23:14:26
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I have the Willem dual power programmer that will not program a 2716 chip. From what I read in the manual this requires a 25v input for burning. I have been able to read the 2716 game ROM chip from my Battlezone game, put in a patch for high score retention and then tried to burn a new 2716 with no luck. It keeps coming up with ERROR message. The jumpers are correct, Bios is in EPP, dips are set for a 2716. When a voltmeter is put to pin 1 and 16 and then write chip is hit there is no voltage present at these pins. When a hardware check is done there is 25v at pin 1 when the dips are changed to the hardware screen. My buddy with lots of knowledge on eprom read/writing is also stumped. The ERROR AT 0X000000 Chip=0X04 Buffer=0XFF keeps coming up. The green and red leds light for a split second and then the usual error message occurs. This seems like a power supply issue, but then again what do I know. Can any one help me on this one as I don't see such info in the forum topics? Thanks Mark.
As of Feb 9th I have managed to burn an old 2716(1982 pinball rom) but have not succeeded in burning 4 new 2716 chips. When these are installed in the 32pin socket and then clamped in place the red led(25volt) goes dim. Remove the chip and the led is bright again. It seems like an internal short in the chips. What are the odds of having 4 new 2716 that are all shorted? Mark.
Feb 10th, I made a mistake, the 2716 I managed to program I acually read the chip first and re-programmed it with hex I just read from
it. As of now its like the other 2716 and wouldn't accept any other program other than what was already programmed into it. As of now all 2716 can be read and will accept the same code re-burned back onto them. Once you alter any of the program and try and re-burn the chip it comes up with the same error as above. It will accept 0000's all day long but deviate from that and the same error comes up. Is there something I'm missing in my hex program that won't allow any altered information to be accepted by these chips. Mark. |
Edited by - Mark Leigh on 02/10/2006 15:46:03
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DL
USA
46 Posts |
Posted - 02/10/2006 : 08:43:18
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Hi Mark,
quote:
Originally posted by Mark Leigh
I have the Willem dual power programmer that will not program a 2716 chip. From what I read in the manual this requires a 25v input for burning.
Watch out for VPP spec changes. 2716 = 25V, 2716A = 21V, 2716B = 12.5V. Programming with VPP too high is the easiest way to damage a device.
quote:
I have been able to read the 2716 game ROM chip from my Battlezone game,
You may not have read the correct data. If you measure VCC while reading, you'll probably see that it drops below 4.5V. I've seen it drop as low as 3V for some devices (i.e. 2532). How low it drops depends on the transistor used on your programmer and how much current the EPROM draws.
quote:
This seems like a power supply issue, but then again what do I know. Can any one help me on this one as I don't see such info in the forum topics?
There should be plenty of posts saying that 2716 and 2732 aren't supported. They draw too much current for transistor switches to handle without having significant saturation voltage drops.
quote:
As of Feb 9th I have managed to burn an old 2716(1982 pinball rom)
The device is probably not programmed reliably. Does it work in the circuit? Guess you couldn't tell unless you could be certain that *all* data was accessed. Problems would show up as unexpected operation.
quote:
but have not succeeded in burning 4 new 2716 chips. When these are installed in the 32pin socket and then clamped in place the red led(25volt) goes dim. Remove the chip and the led is bright again. It seems like an internal short in the chips. What are the odds of having 4 new 2716 that are all shorted?
You shouldn't be having problems with VPP because it should be able to supply the 30-50mA required for programming. Even if it dropped a couple volts, the device might program reliably. It's more important to maintain VCC at the proper voltage because this will have more affect on the device in the intended circuit.
Measure VPP while programming to see if it stays at 25V.
I have a modification that fixes the voltage drop. I add a relay in parallel with the transistor switch and give more voltage options so any EPROM can be programmed reliably. EPROMs should be programmed at VCC=6-6.25V to insure sufficient programming margin. They should be blank verified at 50mV below VCC(min) (4.45V or 4.70V). Obviously a stock programmer won't have those options. My modification will let you set them. If you program this way, you'll be able to insure that the device will read correctly over the full VCC range for a couple decades. Unfortunately, no one is telling newbies that. Doesn't matter as long as you're not programming devices that could put lives at risk...
HTH,
Dennis |
Edited by - DL on 02/10/2006 08:44:28 |
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2716 fails to write
