Galaga (gallag bootleg) arcade repair: debugging CUPL for a replacement daughterboard.

[@marcopantanetti4053]

Good Job Francesco! Very nice repair, Galaga is my favorite arcade game.

[@iz8dwf]

Grazie Marco!

[@senilyDeluxe]

We had a bunch of them in storage and one was missing its daughterboard. I went the exact copy route so I reverse-engineered the connections from one of the others and it worked. (I also have a big stash of 74xx replacement parts and pretty much no FPGAs nor a development environment so... call me old fashioned. I'm also good at reinventing the wheel because I suck at Google) 1st suspect: Video Address Generator. (of course you fixed it already, looking forward to the video)

[@iz8dwf]

Hi! Yes I considered the "old fashioned" way of course, that would have saved me a few months, but when I started this repair, the ATF1502 was a really cheap option, together with the smallest possible PCB. And yes, this boardset had a lot of issues, I need some time to edit the second part of the repair though...

[@iz8dwf]

And by the way, the ATF1502 is not a FPGA, it's a 5V supply CMOS CPLD, like a PAL/GAL on steroids, but it doesn't require any voltage regulator and level translators on I/O. It's one of the best 5V logic chips still in production, it can be re-programmed thousands of times. Its only drawback is that's SMD and probably they're going to discontinue the whole family soon or at the very least the useful (for us old fashioned repairers) speed grades (25ns and 15ns are the most rare now). You only need wincupl and a jtag programmer to design and program with these devices.

[@leeselectronicwidgets]

Great video, thanks for sharing, especially the honesty around design mistakes - that's how we learn!

[@iz8dwf]

Doesn't everyone make mistakes? Indeed it is how we learn :)

[@SurvivalHacking]

Ciao, molto interessante. Hai pubblicato da qualche parte il file di programmazione della CPLD ? Sarei interessato a realizzare uno di quei circuiti per sostituire la DB.

[@iz8dwf]

Ciao, mandami una mail e ti invio i files.

[@deborahberi3249]

Great to see a new video. -Mark.

[@iz8dwf]

Hi Mark, I hope all is well there! I have quite a few repairs done, but so little time to edit videos lately. Anyway, the second part of this one shouldn't take too long...

[@NivagSwerdna]

I'm not familiar with ATF1502 CPLD but it looks like a nice part for a 5V problem. I see you used WinCPL... but how did you program it?

[@iz8dwf]

HI! I've made an "easy" parallel port JTAG adapter, I first convert the jedec file with Atmisp to a SVF file, then I use urjtag on linux. More details are on this video: kzbin.info/www/bejne/sGaop6OqZdWIb9U Unfortunately the Atmel CPLDs are not available in any decent time now.

[@NivagSwerdna]

@@iz8dwf Thanks will check out that video.

[@douro20]

How long have you worked with CPLDs?

[@iz8dwf]

Not much, this is more or less my third working design.

[@patrickspeeckaert1300]

Hi, I managed to 'boot' the Galaxian game on my Bootleg but no inputs works (fire, left, right, start, coin) I changed the LS138 to J7 but nothing changes. Is there an 'open coin door protection' since the 2 pcbs are outside of the chassis Could you help me ? Regards Patrick

[@iz8dwf]

Hi, there's no special switches sensed for that, I always had my cards outside the cabinet. What happens if you switch the test mode on?

[@patrickspeeckaert1300]

@@iz8dwf I put the test mode ON (pin 12 to the ground) power ON white square full screen then multiple colour square and so on Pin 1 of K10 and J10 still to 1 When I switch test mode He begin the game stage 1 But pin 1 K10 and J10 still 1

[@50shadesofbeige88]

Cool!

[@50shadesofbeige88]

What other PCBs are you in the market for? Do you have a list?

[@iz8dwf]

Hi! I'm looking for Galaxian, Moon Cresta, Phoenix, Gyruss. I'm also considering any bootleg of the same era that could run the original game ROMs (as "gallag" can do with the original Galaga ROMs). Then I'm also looking for a Joust PCB, but I guess I must get rich AND very lucky for one of them :)