|
Getting a good read off a bad EPROM
#369940 - 09/27/17 11:42 PM
|
|
|
I've got a 27C512 EPROM from a prototype game that unfortunately is only giving a partial dump, I've heard it appears one address line isn't working, apparently at xxxxx1xxxxxxxxxx = 0xFF
Aside from trying multiple dumps on different programmers and cleaning the legs, are there any tricks people know of that might get me a complete and good read? It only needs to work once!  We're pretty much screwed if we can't get it to dump as there's no other source for that ROM.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369942 - 09/28/17 12:11 AM
|
|
|
If you're using a willem programmer then that's 99.9% chance the problem. But even with good name brand programmers every dumper needs 2 different brands if you want to be a decent dumper in the long term. For example a wellon (not willem which is good for nothing) is solid for a lot of newer chips like surface mount flash chips, but occasionally inexplicably problematic on some older and more simple chips and it can't run things like the Charles MacDonald pal adapter correctly. Anyway I know you said besides using multiple programmers but I've seen that solve issue after issue after issue for all the years I've been dumping. Is it giving consistent crcs?
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369943 - 09/28/17 12:59 AM
|
|
|
The programmer I initially used is a GQ-4X, and I have an old EP-1 I'm going to try too, I'm hoping to have access to the chip again this weekend.
Someone also mentioned the idea of boosting the voltage a little, but I don't know if either programmer allows that.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369944 - 09/28/17 01:02 AM
|
|
|
No do not even put it back in the willem. Put the willem in the garbage and dig out the BP Micro. Willem is the worst programmer on the planet and BP Micro is the best.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369945 - 09/28/17 01:04 AM
|
|
|
I don't have it set up so I can't check, but can an EP-1 even read a 27C512?
Also the GQ-4X says on the back it's made by GQ electronics, are are saying it's the same as a Willem?
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369946 - 09/28/17 01:07 AM
|
|
|
I can't speak for any BP Micro support lists other than for the one I have. But for whatever old chips it supports it's probably going to do a better job on than newer ones, even name brand programmers.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369947 - 09/28/17 01:09 AM
|
|
|
The guy who owns the board with the EPROMs has an older programmer, I have no idea what type it is though, but I'll see if we can give it a shot on that too.
Oh and I might as well ask, what's a good low-budget EPROM programmer, around the $100 range new or used?
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369949 - 09/28/17 01:15 AM
|
|
|
It should read out fine on his programmer if it's anything other than a willem. For $100 if you are looking to dump old games (prior to them using things you need adapters for) then the best BP Micro you can get, which might end up meaning you need a separate old computer for dumping to go with it if it's printer port or old drivers. Old computers work better with old programmers that's for sure.
I've paid under $100 for used BP Micros in the 1200 and 1400 range. They are the best for the buck if you are looking to dump older chips but you might have to watch for them on ebay for a very long time in order to win them at that price but I've done it as have many others. If you're wanting something brand new I don't know, I don't buy them but once every several years.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369950 - 09/28/17 01:21 AM
|
|
|
I just did some quick poking around and it looks like the EP-1 DOES support 27C512's  There may be hope yet!
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369951 - 09/28/17 01:22 AM
|
|
|
Yeah it will read it unless the chip is bad, pretty much.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369953 - 09/28/17 01:34 AM
|
|
|
Someone elsewhere also mentioned the idea of heating it too, is that worth a shot if all else fails?
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369954 - 09/28/17 01:36 AM
|
|
|
If it doesn't read out in 2 different name brand / not willem programmers then yes it's one option.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Tornadoboy]
#369956 - 09/28/17 04:07 AM
|
|
|
> I've got a 27C512 EPROM from a prototype game that unfortunately is only giving a
> partial dump, I've heard it appears one address line isn't working, apparently at
> xxxxx1xxxxxxxxxx = 0xFF
>
> Aside from trying multiple dumps on different programmers and cleaning the legs, are
> there any tricks people know of that might get me a complete and good read? It only
> needs to work once! We're pretty much screwed if we can't get it to dump as there's
> no other source for that ROM.
has somebody confirmed that there is actually missing data
while that error can sometimes indicate there is a dumping problem, it can also sometimes indicate that the unused areas of the rom simply fall on the areas enabled by that address line.
it's one of those 'get somebody who knows what they're doing to analyze the dump' errors.
Edited by Haze (09/28/17 04:09 AM)
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Haze]
#369970 - 09/28/17 12:10 PM
|
|
|
I'm a noob so personally I couldn't be sure of anything, but I gave the dump to someone that definitely knows what they're doing and they're certain it's missing data, apparently this particular ROM is for graphics.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#369976 - 09/28/17 07:34 PM
|
|
|
Turns out the man with the board has an EP-20 and is going to bring it in, so I'll take a shot at it with that too.
|
|
|
|
Re: Getting a good read off a bad EPROM
[Re: Smitdogg]
#370042 - 10/02/17 02:28 AM
|
|
|
Your advice to use an older programmer WORKED, we now have what looks to be a complete set of the ROMs! X1000000
Thanks again for your advice!
|
|
|
Index 
Threaded 
Getting a good read off a bad EPROM
Reply
We're pretty much screwed if we can't get it to dump as there's no other source for that ROM.
[Re: 
There may be hope yet!
