Is it possible to read the 2 video decoder Proms used on the CPU Bd. in Defender?

dogdayaft

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If even possible, I'm trying to verify video Roms 2 & 3 on the Defender CPU board? Parts list says 7641 512X8 proms at location 3E and 3K
Using my GQ-4X4 ,,, units requesting i pick a device?
And since nobody's done a you tube video how to concatenate 512 x 8 PROM, Feel like I'M GOING way out of my league.. but,
been blessed with help here before.. Thanks ,,learning is what its all about..
 
Williams used 7641s on their early solid state pinball games originally, and I guess with Defender being essentially born from pinball, they found another place to use them. otherwise, what's the problem?

here's a way to read them: (which you have posted in previously and found to be a waste of time or something)
 
If you need the code I have them in a .bin file that you can upload to a 2716 or 2732 if you like. You can compare or edit the code or make copies. I once upon a time had a working burner that could read the 7641s but not any longer.
 
geekpcbs.au here in Australia had these readers some time ago on their web site,
designed to be used with modern burners to test the 82S141 , 7641 ROM / decoder chips.
been using one for several years to test these chips,
then geekpcbs have a small daughter board that uses surface mount EEPROM chip to replace damaged 82S141/7641 chips
 

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If you need the code I have them in a .bin file that you can upload to a 2716 or 2732 if you like. You can compare or edit the code or make copies. I once upon a time had a working burner that could read the 7641s but not any longer.
I had to make boards to replace them with w27C512 EEPROMs... I tried 2732s but they just wouldn't work right. I think they weren't fast enough. I've used w27C512s to replace color/sound PROMs as well on other boards... they're pretty much my "go to". I'm still "testing" the Decoder PROM board to make sure everything's actually good... but they've been running in a Defender for a couple of months now with no issues.

For the file you just "copy /b" (in Windows) the file over and over again until it's the right file size (64KB for the 512).
 

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I was able to get both the 2716 and 2732s to work on Defender decoders without any problems. The new Williams games didn't like the EEPROMs when I used them for the #6 Decoder (gave me RAM errors on start up but then worked sometimes). The #4 Decoder seems to work fine. If you need direct 7641 replacement Decoder PROMs hobbyroms.com used the sell them.
 
I don't know why members insist using words like JUST use a binary editor like its that simple,
To someone who's never touched the stuff, it can be troublesome...like concatonate stuff..,
there are a few tutorials on converting 2532's to 2732's ,but why would you go that way, plus it state's in the tutorial its not for writing roms, ONLY FOR READING
https://forums.arcade-museum.com/threads/2532-eprom-adapter.538011/ This is far beyond me,, I'm more of a vacuum tube guy.
when i don't understand something that a KLOV MEMBER spends time explaining using their vast knowledge, i just say thanks and call it a day. SORRY MECHA.
 
it can be confusing if you don't have the experience, for sure.

Why do you want to read them? Is there some specific problem with the PCB? Might be better to go about this from a different angle because it's my understanding these ROMs rarely go bad.
 
it can be confusing if you don't have the experience, for sure.

Why do you want to read them? Is there some specific problem with the PCB? Might be better to go about this from a different angle because it's my understanding these ROMs rarely go bad.
this is entirely my point lol the only way you can kill them is installing them backwards. I've had maybe 2 vertical decoders total go bad the last 10 years.

I don't know why members insist using words like JUST use a binary editor like its that simple,
To someone who's never touched the stuff, it can be troublesome...like concatonate stuff..,
there are a few tutorials on converting 2532's to 2732's ,but why would you go that way, plus it state's in the tutorial its not for writing roms, ONLY FOR READING
https://forums.arcade-museum.com/threads/2532-eprom-adapter.538011/ This is far beyond me,, I'm more of a vacuum tube guy.
when i don't understand something that a KLOV MEMBER spends time explaining using their vast knowledge, i just say thanks and call it a day. SORRY MECHA.
I asked you pretty plainly what the problem was. I didn't mean my post before to come off as condescending, I was just pointing out that someone had a solution for your reading decoder PROMs issue and you posted that you wanted your "game to work without deep diving". I fix games for my job, I had to do a significant amount of deep diving to reach where I am now. @SCUBA King is literally a scuba diving instructor, he rolled up his sleeves and got his hands dirty and he's amassed a lot of wins. if you want help fixing your Williams games I'm here. if you want to play it off like it's too complicated for you then sell your games.
 
Given the amount of defender boards & roms bd.s purchased lately, I've got plenty of time to tinker with them.
they're not worth alot anymore (even the working one's)
and with the theory of operation for defender online as a time burner, its all about what I chose to do with my time.
those two roms are the only ones I can't read? I'm not selling any of my games either.
If you happen to have a 6802 or 6809 pod FOR A FLUKE 9010 Available , lets talk money.
There was a guy selling cat boxes, not the old ones but new designs but have not heard from him.
I would not get involved with those new pods where you need to source your own parts..
worked on PCB's for many years, surface mount, threw hole & multilayer boards..
You have helped me alot over the years, I Thank you...I have limits like high voltage stuff, I do it, but sparingly.
maybe I'll download binary editor one day, but I find alot of people in those tutorials
click so fast and don't realize its a learning device for some... also.. it seems they can't start from page one..

I'm retired , spend alot of my time as a caregiver
no time for vacationing so
I broke open the theory of operation for defender
its a long winded explanation with alot of mistakes ,but, its where i'm at
trying to understand proms but, this one stumps me
I could explain hows a tube amplifier works , but who really cares..
such useless knowledge, Thanks
already bought sets of proms from steph this year TWICE NOW on KLOV
wasting money on cpu boards,, just cause I can...
 
Here is the test "adaptor" i use in my burner,
and the range of Decoder chips.
Green = Defender
Yellow = Stargate
Purple = all other games
 

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You might try reading them as a Cypress CY7C282 or 292. If my memory is correct. I used 282s and 292s to replace them. These are 1k and 2k fast EPROMs respectively so you can use the DOS copy/b command to combine 2 or 4 images to burn . 74S474 is also an equivalent pinout part.
 
You might try reading them as a Cypress CY7C282 or 292. If my memory is correct. I used 282s and 292s to replace them. These are 1k and 2k fast EPROMs respectively so you can use the DOS copy/b command to combine 2 or 4 images to burn . 74S474 is also an equivalent pinout part.
your regular presence is missed!
 
Forgot to post the gerber files. Sorry about that. Dumps to single rail 2716 eprom. Right side is the socket side, left side is the pin side.
 

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