EPROMS with windows uncovered

[RayB]

HI. I just acquired a rare PCB which I'm going to attempt to to make a harness for... but I noticed alot of the EPROMS don't have stickers covering the "window". How sensitive are EPROMS? What are the odds the data on them are corrupt now? (the board's probably 25 years old).

[Witchboard]

I guess it depends on how it was stored.  If it's been in a cabinet for that many years, it's probably fine.  If it's been laying in direct sunlight for that many years... it probably isn't.    You going to tell us what this "rare" PCB is, or keep us in suspense?

[MonitorGuru]

I've read it takes between 2 weeks and 2 months of uninterrupted sunlight at full strength (e.g. no clouds, directly overhead) to erase an EPROM.

Of course a mixed amount of light over time could have caused at least one bit to "turn" rendering it "bad".

The chances are however there are physical issues with the board instead... e.g. dried out capacitors, rusted/broken chip legs, cold solder joints that could have occured during that same amount of time.

I would blame bit rot last after everything else as most boards are not stored in areas with high UV sources. And remember it's shortware UV not longwave UV that erases them, thus in home halogen, incandescent, flourescent, black lighting and plant growing bulbs won't contribute much to erasing them from accidential exposure.

[Stingray]

So come on Ray, what have you got there?

-S

[RayB]

Oh, it's supposedly The Galaxy Empire Strikes Back from Irem.

My guess is that it is a Space Invaders / Galaxian clone from around 1980. But really, the board has no markings, no serial numbers, nothing. Just a piece of masking tape that someone wrote the name of the game on.

I'm going to try and figure out the pin-out... But I've never done something like that before.

[Witchboard]

Well, when you figure it out, write up a how-to, so I can read it. ^_^

[Dav]

Oh, it's supposedly The Galaxy Empire Strikes Back from Irem.

My guess is that it is a Space Invaders / Galaxian clone from around 1980. But really, the board has no markings, no serial numbers, nothing. Just a piece of masking tape that someone wrote the name of the game on.

I'm going to try and figure out the pin-out... But I've never done something like that before.

It's not too hard.   You can tell the power lines easily as they have much fatter traces and then which are which by where they connect to the chips.  From there you can probably get a real good idea from the quickref document.   

This is the quickref for irem.  Actually I have 2 entries in my notes, I think the first is more correct.  It's fairly unique so if it's it you should be able to ID it from the +5(+)  being on the 2 pins 1 away from the end, and the +12(2) being in the middle and ground being on pin 1 and 2.

Code: [Select]

00........22..rb..c++0 ;uniwars/moonpatrol/atomic boy
00......s.22<.g....++0 spelunker1,2,usarally,

00.......S.2<.G...c++0           (22) IREM :MoonPatrol,loderunner,tropiclangel,10yrd ft
00..........<.RB...++. motorace,kid nikki,kung fu master,traverse,zippyrace

Uniwar s is a galaxian type games.  My guess would be a bootleg of uniwar s.

[Dav]

hmmm, the code tag doesn't change to a fixed font?

[RayB]

Thanks for the help. I hope to try to run the board soon...

The weird thing about this board is that it has what looks like a daughter card, with some wiring directly soldered to 3 chip pins. Perhaps this is a modification to some other game...

[GGKoul]

Thanks for the help. I hope to try to run the board soon...

The weird thing about this board is that it has what looks like a daughter card, with some wiring directly soldered to 3 chip pins. Perhaps this is a modification to some other game...

Sounds like a special Clock and Dagger game cart...