Denial

Hi eslapion Ahh... hysteresis. I am begining to grasp this concept... This reminded me of something I had done further back in the discussion on testing the fake ST M27C512-B6 PLA substitue (I do have video of this). Hi eslapion, No worries. I quite understand. Just by the way, I just ran a test of ...

Hi eslapion, The last 2 posts there was talk of "Fastload". Is that Epyx Fastload cartridge? If so, I actually have an original Epyx Fastload cartridge. I found it to work well with all iterations of PLA that I was testing. That is to say Commodore factory PLA, Fake ST M27C512-90B6 PLA, WI...

Hi eslapion and bdk6 I really like #28 Yes.. :D If you can only fine one solution and it is stupid, you have no choice. If it works, it wasn't stupid and you're a here. If it doesn't work, people will say nice things at your funeral. #28 is one best learned BEFORE you encounter it! Agreed.... :D I a...

Hi bdk6,

LOL! Right on.....

Hi eslapion, I do vaguely remember buying one or 2 ceramic DIP ST M27C512-90F6 because I suspected they were the same IC as the plastic DIP '-90B6' but in fact they weren't and caused just as much glitching as Atmel's PROMs. So going for the ceramic DIP version in the hope of getting the same filter...

Hi eslapion, https://www.mouser.com/datasheet/2/389/stmicroelectronics_cd00000518-1204230.pdf There are combinations of letters and numbers that are possible and some that aren't after the M27C512 code and it happens '-90B1' isn't one of them... (see Table 1). So what's on your photo is obviously a ...

Genuine first generation 82S100 used in early C64 boards 326298 were rated for 80ns and that was relatively slow for a logic IC back then. As I indicated, this type of IC was already more or less obsolete when used in the C64 back in late 1982. Commodore made their own equivalent which was rated ab...

Hi eslapion, Oops, sorry about that. I wasn't paying attention.. :oops: The HC = ultra sensitive version chip might be interesting to use. This seller (the EPROM that I have) https://www.aliexpress.com/item/32966311693.html?spm=a2g0s.9042311.0.0.27424c4dNkNzhc Is looking to source some more.. I have...

Hi eslapion, Seems like a good game. :) That is a great tip re using the 74HCT74 for greater sensitivity in the Zaxxon cartridge. I may take me some time turning the schematics into a gerber file for the PCB manfacturer. I will rule out the Magic Desk cartridge to check for glitches. Thanks. I have ...

Hi eslapion, Thank you very much for that information on the oscilloscopes. I will look out for these models on eBay. :D On Super / Zaxxon , I don't think I've ever played the games. Are they good? I found a link here https://www.hackup.net/2018/10/super-zaxxon-replica/ However, I think bigby made i...

Hi eslapion, @banman It's obvious, looking at your photos, this is not a genuine M27C512-90B6 from ST. However, if they do behave correctly as C64 PLA subsitutes then, I guess, who cares... Of course, testing them with the 74LS279 circuit remains mandatory and I still suggest you get your hands on a...

Hi eslapion, No worries. I quite understand. Just by the way, I just ran a test of a C64 assy board No 250407 Rev B on the M26C512 90b for 100 mins. It all seems well no lights have come on within this time. Here is the person I bought the products from. I know the images do not reflect the chips th...

Hi eslapion, Here are some more updated videos of the EPROM based PLA solution with the corrected wiring. C64 Board Assy No. 250407 REV B Testing Commodore Factory PLA https://youtu.be/9drT57Lm3Ms Testing Winbond W27C512 EPROM PLA https://youtu.be/6VSVH0xAetw Testing Winbond W27C512 EPROM PLA with P...

Hi eslapion, Excellent! Good to know you sell replacement PLA's. :D Here are the updated videos of the EPROM based PLA solution with the corrected wiring. C64 Board Assy No. 250407 REV A Testing Winbond W27C512 EPROM PLA https://youtu.be/nH92jWReWzs Testing the Commodore Factory PLA & Testing ST...

Here are some more updated videos of the EPROM based PLA solution with the corrected wiring. C64 Board Assy No. KU 14194HB Board #2 Commodore Factory PLA https://youtu.be/CfOsfLE02zU Testing The Ultimate PLA https://youtu.be/4jxN0SiXJrU Testing ST M27C512 90b EPROM PLA https://youtu.be/aGYbMAjLsDk I...