Can you replace your C64 PLA for under $3?

[@danielmantione]

The reason why the PLAtinum fails is clearly that they have their CAS to CASRAM delay wrong. Later C64 boards uses a resistor+capacitor to delay CASRAM a little bit, and the modifications advised are intented to increase the delay on the mainboard side. Another solution is to replace the multiplexers on the mainboard with faster ones, if you replace the 74LS257 with 74ALS257 or 74F257, PLA compatibility problems are solved. I actually did this on a board with a broken multiplexer, not for compatibility (original PLA was working fine), but just because there wasn't a lot of reason to use the older, slower LS part. As the creators did use a CPLD, they should have been able to route the signals through different macrocells to add delay, just like I was able to do, but they didn't. You need to dig a bit into the low-level details in order to achieve this, perhaps they didn't do this. For me it was't that hard at all to get the CASRAM delays right and I believe most PLA replacements do get it right. The RAM in the C64 has to respond in something in the order of 250ns to the CPU. The entire chain of logic (PLA, multiplexers, RAM itself) has to happen within this 250ns. With 150ns RAM, there is about 100ns left for PLA/multiplexers. The lower bound is approximately 20 ns and this means there is quite a bit of range, the PLA isn't quickly too slow, even above 50ns you would still be on the safe side. However, modern chips are fast, so quickly get in trouble with the lower bound.

[@TheRetroChannel]

Nice work, thanks for another awesome PLA solution and to Adrian for the demonstration

[@megan_alnico]

Amazing! Any idea how close the community is to bring able to build a C64 out of entirely new parts? I believe RetroManCave built an Amiga from all new parts and it would be great to pass that milestone for a C64 also. It would mean the C64 could live forever.

[@danielmantione]

​@@megan_alnico It depends on your definition: The Ultimate64 already can get you a mainboard out of FPGA technology, but yes it uses PLA. Building a C64 from discrete components has progressed, but we still lack good replacements for the VIC-II and CIA. The SID can be considered done. Nevertheless the main enemy of modern replacements is price and it is mostly research into low-cost replacements that has most impact to the community. I.e. even though the SwidSID is technically far inferior to the FPGASID as a SID replacement, the impact of the SwinSID on the community has been much greater, because it the SwinSID fits into the budget people want to spend on repairing a C64, and the FPGASID is outside of that budget.

[@RacerX-]

Awesome work! I will be building some of these for sure. Do you know how this compares to the other popular PLA replacement, the PLAnkton? Provided I can still get stuff from China right now, I will test it on my original Epyx Fastload cart.

[@ukmk3supra]

Would it be possible to amend this project to use the still produced ATF22V10 over the 20V8?

[@kiningroseburg9288]

22:59 "Boom! Blue screen! Looking good!!" Said no system administrator EVER!

[@adriansdigitalbasement]

While editing I thought that too!! Normally bit something anyone wants. LOL

[@mcosta3810]

It's the Blue Screen of Life if you're working on Commodore 64s! Lol

[@nickwallette6201]

Well, that’s how you know you have a properly working Windows 98 install.

[@frugalprepper]

Real administrators have Kernel Panics

[@raginranga3494]

I thought the same.. No BSOD here!

[@branchonequal]

BTW, the exact reason why the PLAs fail is because the glass separating the layers of the die contains too much boron which destroys the aluminum interconnections.

[@leland818]

Thomas Müller - Thank you for that very interesting piece of information

[@branchonequal]

@@leland818 You are welcome! Credit for this goes to Dan Morris, Director Back End Engineering & Manufacturing at Commodore from 1981 to 1985.

[@carlosm4806]

Thanks Thomas

[@metroid031993]

Question on this: Usage of the chip doesn't matter, in terms of wear, right? The reaction would be happening slowly over time anyway?

[@danielmantione]

@@metroid031993 We believe indeed that age is more dominant in failure than actual usage of the chip, but you might be able to prolong their life by keeping your C64 cool.

[@marky26uk]

Hi Adrian, just letting you know i now have all the parts, TL866II PRO Programmer, Gal's, ic sockets, i got the pcb's made at JLCPCB, soldered all sockets/pins to pcb, programmed the gal's which all went through first time with no problems, plugged the gal's into the pcb then plugged the pcb into the pla socket of my c64 and.........wow worked first time with no problems, tried it with fastload cartridge, ultimate ii+ cartridge, loads of games and all worked fantastic. I would just like to thank you for showing us the procedure and parts required Adrian, and a big thank you to Daniël Mantione for his work on this new c64 pla replacement, AWESOME !!!!!!! Thanks guys, love your channel Adrian keep up the good work :)

[@Vermilicious]

I've never used a C64 in my life, but I think it's awesome that people find fixes like these to prolong their use. Kudos!

[@thomassmith4999]

Well worth getting one :) fantastic machines. Best of best of all home computers I would say

[@Sinistar1983]

This community is the best, dedication is the name and craziness is their game

[@raginranga3494]

You need 8bit in your life!

[@osgrov]

This is awesome! Daniël deserves a medal, for sure. :)

[@Sinistar1983]

A international hero, saving thousands of commodores from the landfill.

[@StevenIngram]

I remember the old Pr1me mainframes. When 2 devices tried to communicate on the bus at the same time it generated an error code called, "Fatal Embrace." LOL

[@adriansdigitalbasement]

Ha I love that

[@raginranga3494]

Laughed so hard I woke my wife up

[@MrWaalkman]

So it took awhile to get all of the pieces and parts in, but I built one yesterday and the most challenging thing about it was locating my TL866 to program the GALs. Thanks for the excellent video!

[@alphahr]

The GAL replacement is Great! I now keep 3 or 4 in stock for everything but the short board

[@ddummer]

"Boom! Blue screen... looking good!" ... those were the days long before windows... ;)

[@Jorge_Ramirez]

Thinking the same thing :)

[@PureAudioTones]

I thought the same 😁

[@michaelditto]

Yes, at that moment I coined the phrase "blue screen of life" for use when powering up an untested C64.

[@michaelditto]

And then a few hours later I saw Perifractic use the phrase exactly that way;, so, clearly, I wasn't the first to think of it.

[@DiverCTH]

Guru Meditation #48454C50

[@kaitlyn__L]

Appreciate the cost analysis. Not a lot of people will admit that there's a higher upfront cost from buying in bulk, many will focus only on the final per-unit cost. You put it plainly in the spreadsheet.

[@jamesbennettmusic]

Cheap breadboards are brilliant for holding pin headers for soldering!

[@kneehighspy]

exactly what i use also 👍

[@stevenrhine6994]

Yes, what I Use..

[@edgeeffect]

I've got an old "tired" breadboard especially for the purpose.

[@IrrationalBstrd]

Nice.. used GAL16V8 for project in college, have a few blanks in my box right now... This was in 1997 or 1998 though lol... before the days of usb everything, used a PC LPT PORT, and wrote basic program to output bit patterns to d-latches, to gal16v8 , then the gal16v8 output on 1 of 3 pins depending on menu choice to spin DC motor 3 different speeds, forward or reverse through relays with different resistances (12vdc common on relays for motor, 5vdc driving TTL chips and PLA.. and 2 pins on GAL PLA driving green and red LEDs thru resistors right from gal16v8 (green spinning , red stopped).. worked well and was fun...good times...everyone thought it was awesome, and they see barely anything on my breadboard... Everyone else's projects had huge network of 74 series logic gates, 2 complete breadboards... I just took the same Boolean and wrote it, compiled it and cooked it onto a PLA. Cheating kind of, but not really... Combination of basic program/PC and GAL PLA saved a bunch of tedious breadboard work loI. I was like the only computer savvy person at that time in my class Soni used it to my advantage. Thanks to the old c64, I knew some BASIC which also helped tremendously for the GAL programming... A funny story, the instructor left the room for like 10 minutes one time and I told everyone I was going to play a trick on the instructor... He could never remember the directory names and program names for stuff and always had to pull up directory (c:/dir)... So I went into his PC and did an "C:/attrib +h *.*" .. It finished just in the nick of time before he got back... when he went in there, HE LOST HIS SHIT and I almost got into a lot of trouble. I had to show/explain him the attribute command and what I did.. he was pissed... Lol I think the gal20v8 just has more I/O pins?

[@danielmantione]

Nice read. The GAL20V8 has indeed more IO pins, and also a sligthly larger AND-array than the 16V8.

[@IrrationalBstrd]

Sweet... I actually forgot that it used a 4th pin for polarity switch of the motor through relays, but who cares.. lol

[@ptkx1877]

I had to try this - So I bought enough parts to build 5 units. I soldered one up, programmed the chips, and it booted up perfectly. I have been rigorously testing this, and have yet to find any compatibility issues. Works great with fast load cartridges, 1541 Ultimate, BackBit, etc. Great work on this, and thanks for your videos!

[@iamdarkyoshi]

Lovely solution, kudos to him for giving source code and gerbers instead of just selling them closed source

[@twocvbloke]

It's always impressive to see people using more modern hardware to keep older things working... :)

[@ds_big_pile_of_junk]

I tried this a few weeks ago, and it fixed my breadbin C64! Super easy to make. I routed and etched my own pcbs, but never got to test them because, meanwhile, the china made pcbs from Daniël Mantione's gerbers arrived in the mail. Many thanks Daniël (and Adrian!).

[@PureAudioTones]

Wow, PLA was a big headache for this old machines. I am so glad that Daniel developed an easy solution. Thank you for this complete coverage video Adrian.

[@davefarquhar8230]

This was a good find. I pulled a C-64 out of my boneyard that was giving me a black screen, popped one of these GAL PLAs in, and brought it back to life. My new-life 64 and I thank you!

[@danielmantione]

Those are the messages that make this project so rewarding: Those machines would otherwise not have been fixed. Great!

[@game_whisperer1606]

Great vid Adrian. It’s a no brainier for me to get some of these components on order. Thanks for putting in the links, that made it super easy. Chips and PCBs on order. It’s my first PCBWAY order and they gave me a $5 discount. Total for 5 boards inc shipping to UK was $6. Looking forward to the build. Thank you for the video.

[@rimefancyrats]

I saw and commented this project on PCBWay in January but wasn't sure about it, being open source or not (useless to have PCBs without the JED files). And then baaaaam, it turned out to be completely DIY friendly. Kudos to Daniel.

[@danielmantione]

It was a bit of a dilemma: I was setting up the project on PCBWay and set up my own web site, but didn't want to announce it broadly before this video was ready.

[@adriansdigitalbasement]

Yeah and my fault for not producing the video sooner -- Daniel finished this project months ago and I was the delay!! Sorry about that!

[@Siniad]

@@danielmantione thx, we need more people like you

[@jeffweber8244]

Wow. This jogged my memory of designing circuits using new GAL chips at Raytheon in the late 80s.

[@Aruneh]

I find it cool that people are still making new things for these old machines. Good job Daniël!

[@antonnym214]

Well done! Nicely-presented and explained. Really good work, from a technical aspect as well, and BONUS, I had never seen Super Zaxxon on the C64 and it's gorgeous!

[@JerryEricsson]

The games on the Commodore were fantastic! Many of them were beyond belief for the speed and size of the little machine. The only problem I can recall with all my Commodores was the speed to load a program. It was like : Load *,8,1 then go for coffee down town with the guys, return from coffee to see either LOADING... or PRESS ANY KEY TO CONTINUE. Over the years I owned the C=128 then found a great deal on a C=64, then a buddy got an IBM and sold me his C=64SX which was great, I had that after my first spinal repair surgery, when I was laid up, it was wonderful to have that little brief case machine beside my bed, a joystick in my hands and FROGGER loaded for play. Later I picked up a new Commodore +4 and played with it for a month or so, then put some pro-gun data in a scrolling basic program and took it to a gun show. Got an Ithaca 10 gauge goose gun double barrel in trade for her. Later my nephew gave me his VIC20 with monitor and 1541, I think that is in the back room somewhere, the monitor is sitting atop a pile of old laptops back there I think.

[@albertdelafuente9977]

Cuando eramos 35 años más jóvenes disfrutamos del software y periféricos del C64, ahora seguimos disfrutando igual pero además de su electrónica fabricando y adaptando nuevos chips para reparaciones y demás, buen trabajo Adrian, gracias a tu vídeo me he fabricado mis PLA funcionando estupendamente.

[@mrb5217]

Great timing on this video. I was just putting in an order for 3 other PCBs I'm working on. A C64 / C64C compatible RF Modulator replacement, a 50hz clock generator for running PAL 64s in NTSC land, and a VIC-II 856x adapter that lets you run 5V C64C VIC-IIs in 12V breadbin motherboards.

[@adriansdigitalbasement]

Neat do you have links to those PCBs? I'd be very curious about all of those!

[@mrb5217]

@@adriansdigitalbasement Hi Adrian :) I actually just designed the PCBs this weekend and sent them off to be made. As soon as I get a couple built up (and if if they work as expected!) I would be happy to send you one of each. Once I know they work, I'll get all the kicad and gerber files up on github too if anyone wants to make their own. Feel free to shoot me an email at my KZbin username (at) gmail.com and we can chat more about them.

[@BarnokRetro]

Made up 10 of these when I needed one for a dead C64 on my bench, and I just found a rusted off pin on another machine. Two C64s back in working order thanks to this video! Building 10 was cheaper than buying a couple on Ebay, so it even made economic sense to have a chance to get out the soldering iron!

[@connorstrothman7287]

You might be able to talk to The 8-Bit Guy about testing the Epyx Fastload cartridge.

[@Sinistar1983]

That's a good idea

[@tpcdude]

Pals and gals were great technology, my company used a pal to replace a part on DEC Unibus interface that they would not sell us since we were a competitor. Also, in the telephone industry when two sides of an interface were enabled at the same time we called that "glare" since both sides would just look at each other and do nothing.

[@outseeker]

i love when people take the time and effort to make things for old gear like this for everyone to have :)

[@duodream]

I have some PLA alternatives that were a bit expensive (for a single chip). This idea is great. I can keep a handfull of these in-stock for my machines. I ordered 10 boards and enough GALs, and it cost less than most of the other single PLA replacements. Now if we could only get an inexpensive VICII replacement...

[@raymondheath7668]

Great info, dead PLA's have been the bane of my existence. I'll have to try it on my Sx-64

[@adriansdigitalbasement]

Get some of these made up! Assembly line make them and you'll never need to worry again. :-)

[@thomassmith4999]

@@adriansdigitalbasement I've replaced the PLAs in most of my C64s but still have a few that are working (other than the PLAs) so these will be perfect for me. Next problem is a CIA replacement :)

[@timpsensky5181]

I'm so glad you did this video. I ordered these PCBs a few weeks ago and am still waiting on them. I have had bad luck making replacement PLAs from EPROMS and CPLDs and have been using the PLAnkton, but have been looking for a lower cost/more DIY solution.

[@adriansdigitalbasement]

Yeah Daniel finished this program months ago and I've been sitting on them trying to get the video made and put out. Don't worry, your PLAs will definitely work perfectly!

[@brianv2871]

I can vouch for this as well, mine all worked as well.

[@MoraFermi]

This is possibly the only time where somebody is excited to see a bluescreen.

[@andik6828]

Excellent tip using a dummy socket to get everything straight, great vid again Adrian thanks

[@overdriver99]

since I have 2 dead C64 with new PLAtinum I understand what happened. and thanks for very very clear PLA functionality. I had no idea what it does. Because I sux with soldering,etc I would not build PLA as you describe but you & your buddy are great to make some effort to rescue more broken C64. Thank you.

[@adriansdigitalbasement]

I really feel like even the most amateur soldering skills are good enough to make these.

[@lactobacillusprime]

I am using a replacement PLA on my C64 Reloaded board. This SuperPLA works quite well. But the DIY GAL-PLA project from the Netherlands is great! :)

[@MindFlareRetro]

Fantastic video, Adrian. Your explanation of PLA's function is perfect and easy for people to understand. I am going to be ordering some PCBs and GALs - I do have an original FastLoad cartridge and can give it a test. Also, thanks very much for including the link to my 'The PLAin Truth About the Commodore 64 PLA' video. Hopefully, your viewers find it informative. Excellent work, as always. /\/\FR

[@danielmantione]

Adrian did a good job :) Please let me know your testing results, so I can update the web page.

[@adriansdigitalbasement]

Yeah what a great video -- I watched it a while back before I knew of Daniel's awesome project. Yeah can't wait to see more testing done by others to discover just how compatible this PLA is.

[@MindFlareRetro]

@@danielmantioneFirst of all, great work, Daniël. I just ordered GALs and will order PCBs soon. I will keep everyone posted. Thanks guys.

[@gregorymalchuk272]

@@MindFlareRetro Update

[@BlackEpyon]

I love that TL866. Sure, it doesn't do the high voltage that the old chips used for programming, but it's pretty universal where newer EEPROMs and PLAs are concerned (like all these retro projects use), and it's also able to test logic ICs for faults, making it very handy as a diagnostic tool. Definitely worth what you pay for it.

[@adriansdigitalbasement]

My old first generation TL866 can do 21v programming which is just enough to do chips like the 2764 and 2732. (even though those call for 25v typically.) It's a shame they reduced the maximum voltage with the current one.

[@VladoT]

I can also confirm that the older TL866 programs high voltage EPROMs just fine.

[@simontay4851]

Could you feed in higher voltage externally to chips that need it or modify the tl866 with an external power input. Generating 25V with enough current from 5V is not easy. Thats probably why the newer model is 18V max.

[@BlackEpyon]

@@adriansdigitalbasement Mine is the TL866 II Plus. Just wish it could do logic tests on the 74x688 chips (it does everything else). Did yours need an external power adapter for high voltage programming, or does it have a voltage multiplier circuit inside?

[@BlackEpyon]

@Marcel H Yeah, why DID they drop the 21v option anyways? Was it unstable?

[@Colin2084]

This is really informative and the solution looks awesome. I've ran into timing issues myself using CPLD's with some Atari arcade boards while working on solutions to replace custom chip devices. The original systems 'kind of just about worked' timing wise. Nothing too fancy, but certainly becomes an issue when trying to replace old logic with modern(ish) equivalents which run a fair few nanoseconds faster.

[@steveedwards4635]

I've never owned or used a C64, but the deep geek in me found your video too hard to resist! What a treat! 👍🏾

[@kingey71]

My order of 50 boards from PCBWay is on it's way to Australia. I repaired C64's (among a ton of other stuff too) back in the day and still do. Although this batch will most likely end up in the units I have in my possession for restoration I am happy to help others too.

[@whisk0r]

I keep a solderless breadboard on my bench just for those moments when you need to keep headers strait while soldering them, works every time.

[@IntegerOfDoom]

As awesome as powerful as modern computers are I find this classic hardware infinitely more interesting.

[@scelbi8h]

I bought 40 GAL chips from Aliexpress. When I programmed them, I got the same "Overcurrent protection action! External short circuit/IC reverse or damaged!" message with over 20 of these ICs. But that doesn't mean they are bad - I selected the "erase" option on the software and I got an overall count of 39 working GALs. Finally only one of them was really faulty. I think many of the "faulty" GALs Adrian is showing here are really working. It is worth to try the "Erase" option with them. About the GAL PLAs, they are just awesome. I don't think I will need any replacement any time soon - I built 17! Everything just work with them :)

[@danielmantione]

Try to reduce the programming voltage to 14 volt. The official voltage for the GAL20V8B from Lattice is 14.5 Volt. The TL866 cannot generate 14.5 Volt and I guess this is the reason why it defaults to 16V. This works most of the time, but my experience is that some GALs don't like this, in such case, lowering the voltage to 14V fixes the "Overcurrent" messages.

[@frugalprepper]

This is a great video Adrian. My PLA is working for now, but I ordered 10 of these chips to keep on hand in my parts bin so I will have them if I need them. Next time I am getting some boards at OSH Park, I will get some of these made to have as well. I already have a programmer from having to make a new rom for my VIC 20. This is my first time using the ALI Express. It will be interesting.

[@beanboy5315]

Nice video. Was looking forward to that dance party though.

[@adriansdigitalbasement]

Sorry I short changed everyone :-)

[@darkstatehk]

This Is great! It would be legendary if Daniel solved the VIC-II dilemma / HDMI out problem. That issue has been so evasive for such a while now. Thanks for sharing this!

[@SOU6900]

I like videos like this. Old mother boards are neat because you can add, remove and even change chips. Mother boards that have expandable onboard cashe come to mind. And ones where you have to set jumpers or dip switches are cool too.

[@KorAllRBare]

Had to chuckle when yo said "BOOM! Blue screen" with massive glee, As normally "well with windows only" a Blue screen invokes quite the opposite sentiment to Glee.. oh yeah I dropped a like..

[@leozendo3500]

Insanely good project. I always love these engineering intensive projects involving resuing old retired high performance ICs. You can get 500Mhz bandwidth ADC ICs for 3 US dollars but an entry-level 500Mhz Oscilloscope costs around 300.

[@DevilsHandyman]

I have a C64 that I need to get back up and running. Fortunately the PLA seems to be okay but this is a good resource just in case. I love your shirt. One of my first computers was a TRS-80 Model I (4KB).

[@danielmantione]

If the PLA is fine, check if you have Micron MT4264 RAM, those also fail in hordes. If the PLA is fine, you can also likely try a dead test cartridge to get an idea where the fault it.

[@Arcadecomponentscom]

Adrian - I highly recommend the P-34 pliers from Hozan for straightening chip pins. The thin jaws fit between pin legs and the flat jaws make short work of straightening the worst pins.

[@aztockdog]

Wow, so interesting to see all of these projects to help our C64s to keep on keepin’ on! Thanks for sharing :) Great vid. Subbed.

[@poitsplace]

I recently realized something that would have been really handy for commodore to have done with logic chips. If they'd added another 8bits of IO and made it active on the address bus with the PLA, they could have made a zero page pointer that would have allowed a faster, indexed access of all of the 64's memory. Kind of like the page pointer they added to the 6809, only without having to screw with the CPU.

[@PacoOtaktay]

This looks like a great project. I just recently had to dig through some old C64 parts to fix my C64 as the PLA died and took the ROM's with it. Thankfully Jim Brain (go4retro) had some 2364 adapters so I could just use 28C64 chips to replace the KERNEL ROM's in my C64.

[@David_Ladd]

This is for sure a great project. I managed to download the gerber files and had a batch of PCB's made up. I also ordered the chips and got them programmed. So far the testing has gone great. My 1541's and the SD2IEC I got from GO4RETRO seems to work on the C64 that I put this project into. Thank you for sharing this project. Another C64 saved from dead PLA MOS chip.

[@The.Doctor.Venkman]

20% of the GALs (20V10D, 16V8 etc. all Lattice) I bought from AliExpress where shagged! But, the cost of these as a whole is good value for money for the ones I got that worked. I also used the new version of the TL-866II. Thanks for the great videos you make, Adrian.

[@hamiltonguy6922]

@Andy: What new version of the TL-866II?

[@The.Doctor.Venkman]

@@hamiltonguy6922 - Bought the original TL-866 and that worked for years until one day I updated the firmware and they bricked my device for which I was furious as they told me it was counterfeit and it was not! EEVBLOG had a big discussion about this as it was the same situation as with the FTDI bricking. EEVBLOG members even provided new firmware to re-flash the device, but I never got it working again. Anyway, I had to buy another one and they had brought out an updated version II - Here's one as an example: www.aliexpress.com/item/33009345108.html?spm=a2g0o.productlist.0.0.1469538fWWsAmL&algo_pvid=459e40e8-b7a9-4dad-be26-cdb0378d2917&algo_expid=459e40e8-b7a9-4dad-be26-cdb0378d2917-0&btsid=0b0a01f815842929603823043e085a&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

[@hamiltonguy6922]

@@The.Doctor.Venkman Thanks for sharing! I was on their website www.autoelectric.cn and it looks like an even newer one is coming; has anyone heard about this? forums.xgecu.com/redirect.php?tid=14&goto=lastpost#lastpost

[@hamiltonguy6922]

@@The.Doctor.Venkman If I read the specs correctly it can handle higher voltages which the older TL866s could but the newer ones can't

[@The.Doctor.Venkman]

@@hamiltonguy6922 - Thanks for the update. This is good to know as I hadn't looked for a while.

[@VladoT]

This is probably the only video that mentioned PCBway because you actually need the pcb and is not sponsored 😀

[@adriansdigitalbasement]

Heh, I'm not sponsored by anyone (by choice.) I actually don't really use them myself but they are the only ones that allow you to easily upload your project so anyone can one click order it. (Well of the chinese makers.) I prefer JLPCB personally -- better pricing.

[@VladoT]

@@adriansdigitalbasement I hope it stays this way because a lot of KZbinrs carried away by quick money start to bloat their videos with sponsored content that would be irrelevant in a year or two. Great content by the way and good luck.

[@Wes8761]

7:03 hey its my breadbin revision. My 64C uses the boars you showed before with the 8701

[@kissingfrogs]

This was an excellent upload. Thanks Adrian.

[@nemoskull2262]

thank you so much for including actual out the door cost.

[@ThereIsOnly1ArcNinja]

Damn, it really took me over 30 years to realise, that we C64-afficianados prefer to get a blue screen - in contrast to Windows

[@quirin1727]

Blue Screen! C64 User: Yeah, it works! 👍 Windows User:😞

[@Arcadecomponentscom]

PLS100 is the other PLA chip. It's pin compatible with the 82S100 and is what I used on my last run of NOS PLA replacements.

[@adriansdigitalbasement]

AH yes that's right -- the PLS100. There are some Soviet clones of these chips that are apparently around too. Can you find the PLS100 anymore? (Blank)

[@Arcadecomponentscom]

It's difficult, but sometimes you can. Folks on eBay are crazy with their pricing and some of the chips have house part #s on them, meaning they have already been programmed! I try to find them in small town mom & pop electronics shops. That's the only way I've found to get a decent price.

[@ezContents]

Thank you for this great explanation and demonstration on how to replace the PLA.

[@Plan-C]

Great and detailed video as usual. Looks like the DodgyPLA is better than the PLAtinum. I etched 5 at home lol. I think probably the best is the PLAnkton. Gonna try a GAL PLA. ps @11:18, I always though that was corruption but it appears not. The PLAnkton and DodgyPLA show that same brief flash as the MOS PLA... Keep them coming...

[@matthewday7565]

Windows user - reacts with horror at blue screen C64 user - blue screen is my friend

[@xanderplayz3446]

I use ctrl+2 btw

[@Mr_ToR]

I ordered these chips about 10 minutes after this video was released.

[@Mr_ToR]

I used jlcpcb as usual instead of pcbway since pcbway was more expensive.

[@johnhoogstra8310]

I'm so going to do this. Thx for bringing this to my attention :-)

[@dan_loup]

"oh yes, my computer bluescreened, which means it worked!"

[@giumacgyver7127]

Dr_Kachu san yep, awesome reason to state that

[@ovalteen4404]

Good on C64. Bad on Windows.

[@KuraIthys]

Also good on atari micros. XD I do wonder why Windows chose blue for that. Though I guess the default colours for lots of things in windows have always been blue...

[@dan_loup]

@@KuraIthys Maybe they did it to match the old DOS programming editors, as they generally used blue on white.

[@daves.software]

Actually if you read some of Linus Torvalds' accounts of the early days of the Linux kernel, he often debugged using a technique where if the system re-booted, he knew the code was right.

[@jsanpe35]

Really awesome video and project. Build myself a couple of these and work great. Thanks for sharing!

[@eformance]

As I understand, ULA is a designation whereby the base silicon mask is designed as a bunch of uncommitted logic, then the customer tells the fab how they want them connected, and they put a metal mask layer on top of the uncommitted logic to connect the logic together. It's sort of like a par-cooked IC. I assume the Commodore PLA is just a ULA by a different name.

[@adriansdigitalbasement]

Maybe except Commodore themselves were making it ... So not sure why they would have any extra steps.

[@Arcadecomponentscom]

Commodore had the fab. It was cheaper for them to roll their own mask programmed device and skip all the programming steps.

[@fdameron]

You also want to clean off the flux with alcohal after soldering since the rosin core flux can damage the circuit board over time.

[@Renville80]

Floyd Dameron Organic core solder is even worse, especially since it’s more soluble in water than with alcohol. On top of that, organic is far more electrically conductive than rosin.

[@fdameron]

@@Renville80 Good to know. Thanks for the reply.

[@MrPDawes]

Makes me want to buy a C64. Never had one when I was a kid as I had a BBC Microcomputer. Better machine in many ways but not many games written for it like the C64.

[@slammed]

Thank you for the incredible explanation. Love your videos.

[@ches74]

We were using Lattice GALs in avionics comms equipment. I had to requal to use PALs as they still make those. I've not compared the spec but PALCE20V8 would likely work just as well. Not that you're likely to find those anywhere near as cheap as the AE GAL prices!

[@danielmantione]

PALCE20V8 would in all likelyness technically work, but I wanted a part that the TL866 could program. I was doubting between the ATF22V10 and GAL20V8. The ATF22V10 has the advantage that it is still in production today, but the disadvantage that only the TL866-II can program it and not the first TL866. Because there seem to be more than enough GAL20V8s available to repair for all the C64s still in use, I decided that compatibility with all TL866 programmers would make it most useful to people.

[@ches74]

@@danielmantione As I remember amongst the options I also qualified some e2v parts, they use Cypress die, and there were some quirks in programming even with our ancient obsolete programmer. In theory they're the same but it's not always so easy in practice. Great work coming up with what looks to be a universal solution.

[@RetroGameCoders]

Daniël Mantione I’ve got some of the atmel chips and a fast load is on its way from Ontario as I type this, will try when it’s all here

[@adriansdigitalbasement]

Yeah I was actually curious, can we use the ATMEL 20V8 chips? (OR whatever the part number is.) Aren't they basically the same or compatible with the Lattice part?

[@ches74]

@@adriansdigitalbasement I believe GAL and PAL with the same designation are functionally the same. The avionics kit I mentioned was designed with a GAL because it's handy to have a reprogrammable device when in development. Then over the next 30 years of service they didn't get around to changing to PAL until obsolescence struck. As you touched upon, Timing is the usual concern. When they're the same on paper they should work fine but it's only testing that'll prove there aren't any quirks in the die.

[@BigCar2]

You were a little mean to the PLAtinum chip. Yes, it's not as good, but the folks behind it worked hard to create something to benefit the C64 community, probably not really making any money out of it. They should also be applauded for trying to help solve this problem.

[@danielmantione]

Absolutely, a machine with PLAtinum with proper mods counts certainly as repaired, which is the goal. I greet everyone who contributes to preserve the C64 heritage and we should be thankfull their contribution to our shared goal.

[@CDP-1802]

Interesting fact, MOS Technology was always pronounced "M. O. S." Technology by the people who worked there so it was not to be confused with Mostek, another chip manufacturer. :)

[@chrisjpf33]

Thank you for making this point. This bothers me a lot. I personally know several people who worked at Commodore and they all agree it is not pronounced "moss" but "em oh ess". I hope this information gets around to people who make vintage computer videos like this so that we can preserve true computer history.

[@KuraIthys]

Ah, the days when seeing a blue screen on your computer was a GOOD thing. I may not own a c64, but the Atari 800XL also has a blue screen by default. (which I usually change to purple a few seconds later, but that's a different matter. XD)

[@series80]

great video, and although I do not have a C64 I enjoyed it for the information on the replacement of PALs with GALs. I have two comments, the first is that cheap turned-pin DIP sockets are in many cases one use - when you try to remove the IC, the rings inside the socket hole come out and then you have to replace the socket, so you only save the chip, but you still need to replace the socket. In other words it defeats the purpose of having a socket. I generally buy good quality sockets from reputable suppliers. the second comment applies to the motherboard socket. Notice that the adapter pins are much thicker that the IC pins. This means that each time you insert the adapter you bend the socket pins a lot more then if you were to insert an IC. So you should consider the insertion of the adapter as a one-off operation and refrain from removing it and reinserting it as we see in the video. **vp

[@danielmantione]

The pin headers that Adrian and me are using (and referring to) are perfect for inserting into mainboard sockets. They don't bend the socket pins more than normal and fit perfectly both into leaf spring sockets as well as in machined pin sockets. Also machined pin sockets from AliExpress are in general of acceptable quality, and can certainly be used more than once. That said, I often prefer dual wipe leaf spring sockets for these old computers.

[@adriansdigitalbasement]

Yeah I've used those round hole sockets for a while now (always from China) and have never had one fail yet. The ones in my ZIF-64 have had chips put in and taken out many many times without issue. Infact, on that machine, I'm testing chips removed from other machines -- so the IC pins are covered in solder and other crap and still no issues. And yes, the pin headers I link to are super slim pins that work fine in all sockets. Different than the much larger square pins that are commonly found super cheap.

[@bobblum5973]

Excellent test & review of an excellent product, with plenty of detail explaining how it works. What more could you ask for? 👍😎👍

[@Bushougoma]

Another peril of relying on Aliexpress or E-bay is the high probability of counterfeits. They sand the original part numbers off of the chips blacktop them (cover them with black paint) and relabel them. I wouldn't trust the speeds written on ANY of those chips personally. Heck the chip that read as a short circuit may have never been a PLA at all they could have just taken a chip with the right number of pins and printed the part number on it. I purchased 120 NS EPROMs off E-bay (before I knew about counterfeit chips) they were labeled ST Semi CMOS when in reality they were National Semiconductor NMOS 200 NS parts. I found this out when I read the manufacturing code out of the EPROM with my programmer. This wasn't an issue in my application but I was kind of pissed.

[@AiOinc1]

The 906114-01 is indeed programmable - One time. Lots of early programmable chips (including microcontrollers even) were typically only programmable once. In the case of chips like PLAs, they are large gate arrays with fuses inside which can be destroyed depending on your configuration. This is done in the factory, so before the "programming" process, it is just a generic array of gates.

[@adriansdigitalbasement]

I am told by multiple people this is not the case and it is manufactured already with the programming inside. This is unlike the 82S100 and 93459PC (fairchild) which needed to be programmed (once) before use.

[@Arcadecomponentscom]

NO! The 906114-01 is a mask programmed device. It is programmed during creation by the way they deposit the circuitry layers on the silicon chip. It does not have fuses inside it and is not fuse programmed like the 82S100 or PLS100 devices. Commodore DID use some 82S100 and PLS100 devices in production C64s when they ran out of the mask ones. This was how I was able to dump the PLA code - I found one of the Commodore 64s that had an 82S100 in it.

[@berntolovhellstrom8891]

The board you populated should have two 100nF decoupling capacitors. The reason is to keep the voltage constant while the gates are switching and could cause a voltage drop. I strongly recommend to have two, no longer than 0.5 inch away especially now when the PLA are faster than originally.

[@danielmantione]

I rejected this in the interrest of keeping the solution as dead simple as possible. The power consumption of the GAL20V8 is way lower than the original PLA, thus the switching noise should be also way lower than the original PLA. The effects on the power line have been analyzed with an oscilloscope and the conclusion was that decoupling capacitors would not be of much use.

[@stephenwhite506]

The motherboard has a capacitor on it for the original PLA.

[@berntolovhellstrom8891]

@@stephenwhite506 It is good practice to have the decoupling wires total length less than one inch. It won't be that here.

[@berntolovhellstrom8891]

@@danielmantione The decoupling capacitors purpose is to take care of the transients, the ability to keep the supply voltage when the gates are switching and not for the steady state power consumption. You are free to do whatever you want but if this product was going to be produced in higer volumes, you would see some of them failing do to variations in some batches of GALs.

[@stephenwhite506]

@@berntolovhellstrom8891 I would disagree on the distance. If you are that fussy then solder them across the top of the chip.

[@jason50146]

"A bad PLA results in a black screen." Or a blue screen, or a rainbow screen, or a psychedelic screen, or a garbage screen, or messed up characters, or horizontal stripes, or...

[@brianv2871]

True. Maybe it's better to say a dead PLA, since a bad PLA can do just about anything.

[@An_Onion]

@@brianv2871 but can it explain why kids love the taste of Cinnamon Toast Crunch?

[@wesleymays1931]

@@An_Onion mmmmmm cinnamon toast crunch mmmMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM

[@raginranga3494]

Would a bad PLA make the screen flicker to the beat of what music is playing?

[@wesleymays1931]

@@raginranga3494 No joke, your comment made me start headbanging.

[@diezam]

You sir are a gentleman and a scholar

[@AndrewTubbiolo]

Another great video! Just a few months ago I was thinking if anyone would make a PAL replacement when the OEM equipment dies.

[@adriansdigitalbasement]

There have been replacements for a while but never such an easy DIY PLA for so cheap. :-)

[@AndrewTubbiolo]

@@adriansdigitalbasement Waiting for the first mother board populated with FPGA and the such replacement parts for the major components as the years go on.

[@TomStorey96]

@@AndrewTubbiolo will become more and more difficult. FPGAs are already difficult because they operate from lower voltages, 3.3V and below. Maybe you can just scrape in if the rest of the chips have TTL compatible inputs, because 3.3V is just good enough for logic high with those. No such luck if they are CMOS only, but I think that is unlikely in a C64. Modern technology doesn't tend to cater for technology from decades ago, it wants to move forward.

[@Sinistar1983]

Thank you, now I can finish a commodore at a reasonable price

[@chriswatson2407]

Very well done to you both

[@wadz668]

I don't know if you ever found out about EPYX fastload and the GAL-PLA. I have an original Fastload cart and the GAL PLA. Yes, it DOES in fact work!

[@richiemiller5691]

I just bought 2 kits from Daniel and it looks like the chips come preprogrammed: "You will receive: 1 * adapter PCB 2 * 14 pin header, round pins 2 * DIP socket 24 pins narrow 2 * GAL20V8B chips, preprogrammed and tested in a C64 1 * Instruction manual This is pretty nice.

[@borayurt66]

I have been looking for a budget eprom programmer, thanks for the info, I ordered one right away!

[@kins749]

Awesome work by all involved!!!

[@borayurt66]

I wish there were a simple & cheap alternative for the Spectrum ULA too. Unfortunately the ULA is a lot complex, can be replicated with a FPGA but not this easy and cheap approach.

[@raymondheath7668]

I would love to see a comparison of aftermarket SID chip replacements

[@madmartigan1498]

Really great news. Thx for sharing! Btw great videos, love your channel.

[@Wes8761]

Like the bus transceivers on the vics

[@tschak909]

Later MOS made PLA's had passivation layer issues (too much boron).

[@garthhowe297]

I don't even have a C64, but love the content nonetheless.

[@5mf1nc]

Some tips: You can also solder the pin-header if stack 2-3 PCBs then put the pins there to hold them. You may need to gently push on the PCB to be soldered to to align them vertically first. Also the GALs are sometimes(?) not fully reliable with this programmer, you may need to programs them 2-3x times (deselect Erase before programming) to prevent some bits flipping later in use (learned the hard way--- killed like 6 CPUs in my Falcon)

[@adriansdigitalbasement]

Ah yes good tips -- especially on stacking the PCBs. :-) I've found sometimes I need to program EPROMs are few times as well -- just for best reliability.