Got my circuit boards back....

Got my circuit boards back....

Hans
Hans

November 1st, 2011, 6:13 am #1


Worked like a charm, after I got my head out of my ass and loaded the proper software onto the EPROM. Nothing too complex really, just a nice little daugher board that fits into the old CPU socket and lets me use a single EPROM. Sure beats having to hack traces on the original board.

The two LED's are there just as quickie diagnostics for checking the +5v and the reset power lines. I sized the board to take 1/8w resistors, but only had 1/4w on hand. Whoops.



-Hans
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sniper1rfa
sniper1rfa

November 1st, 2011, 11:30 am #2

That looks like it has an LED drilled into the middle of it...

looks sweet.
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Derek
Derek

November 1st, 2011, 11:35 am #3

An EPROM NMOS IC. And yes, it looks very cool indeed.
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Joined: April 18th, 2005, 4:54 pm

November 1st, 2011, 3:57 pm #4

That looks like it has an LED drilled into the middle of it...

looks sweet.
Just a standard EPROM chip actually. They erase via UV light hitting the memory array, so they have to have that quartz window to allow UV light to pass through the chip body. Normally that window is covered via a label or something else to protect it from accidental erasure.

I just thought it looked cooler with the guts exposed like that

-Hans
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Derek
Derek

November 1st, 2011, 10:11 pm #5

I'm not an avid electronic tinkerer, so I'm EPROM-uninitiated, but that's cool. You just flash it with a little blacklight? Or is it lower frequency?
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Fonz
Fonz

November 1st, 2011, 10:40 pm #6

Worked like a charm, after I got my head out of my ass and loaded the proper software onto the EPROM. Nothing too complex really, just a nice little daugher board that fits into the old CPU socket and lets me use a single EPROM. Sure beats having to hack traces on the original board.

The two LED's are there just as quickie diagnostics for checking the +5v and the reset power lines. I sized the board to take 1/8w resistors, but only had 1/4w on hand. Whoops.



-Hans
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Joined: April 18th, 2005, 4:54 pm

November 1st, 2011, 10:57 pm #7

One of the more popular old machines, called Firepower, has a few obsolete ROM chips on it that simply aren't available anymore.

This lets you use a single EPROM in place of 6 lower capacity chips, without any of the tricky board modifications that other methods use to deal with those unavailable chips.

-Hans
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Joined: April 18th, 2005, 4:54 pm

November 1st, 2011, 10:58 pm #8

I'm not an avid electronic tinkerer, so I'm EPROM-uninitiated, but that's cool. You just flash it with a little blacklight? Or is it lower frequency?
Takes a couple minutes of direct UV light, at a certain wavelength, and it blanks it right out.

-Hans
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Levi
Levi

November 2nd, 2011, 7:44 am #9

Worked like a charm, after I got my head out of my ass and loaded the proper software onto the EPROM. Nothing too complex really, just a nice little daugher board that fits into the old CPU socket and lets me use a single EPROM. Sure beats having to hack traces on the original board.

The two LED's are there just as quickie diagnostics for checking the +5v and the reset power lines. I sized the board to take 1/8w resistors, but only had 1/4w on hand. Whoops.



-Hans
Those look really good man! i love getting to look into the eeproms and seeing the die. (side note, if you decap flash ram, you can clear it with UV. check out bunnie hacking blog for some use of this)

i was hoping to post up picks of my work (they showed up today) but sadly the boss said no public pics for awhile

keep up the good work!

-Levi
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Hans
Hans

November 2nd, 2011, 9:32 am #10

I know when it comes down to it, this is a VERY simple little board. Complicated compared to anything I've done before, but turd simple in the grand scheme of things. But considering I'm pretty much teaching myself the entire process as I go, both in hardware design as well as board layout, I'm pretty darned happy that it fired up on the first try. That, and people want to buy them (kinda knew the market was there).

Here's another fun one when it comes to EPROM's. I stumbled onto an article that says EPROM's and PROM's are essentially the same, other than the quartz window. You can use above average powered x-rays on either one of them to blank them out, as it's simply the application of energy that does the actual work. But x-rays risk burning them out, so it's rarely used.

I've already got a couple other projects on the table, some more complicated than others, but I'm really enjoying this work so far.

-Hans
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