Need help identifying a 7-wire PIC 12C508 PlayStation mod chip on PU-18/SCPH-5501

Depends on what clock rate it ends up working at - if it's way off frequency then all the SCEx messages would be corrupted and the disc wouldn't be recognized as being licensed at all. If it's rather less off frequency then it will occasionally give the "not a playstation disc" screen, sometimes boot to the black screen and then hang on the second security check and sometimes boot.

I did a test on this back in the day - set the chip to external clock and wired a function generator to the clock pin. It still worked OK even with a +/- 10% clock error (I.E. 3.6-4.4MHz) , which was wider than the data sheet limits for 0-70c operation. Bad calibration data (or just leaving the cal location blank) can drive the clock off by a lot more than that, though.

Also note that at one point a lot (possibly even most) of the low-cost multi programmers didn't handle the calibration values on PICs properly.

 

I find some programmers still struggle with it. When I first started toying around with PICs, this became invaluable on saving chips:

http://picprojects.org.uk/projects/piccal.htm

 

Using a TL866A here. The OSCCAL value is blank and grayed out, presumably because the software knows I shouldn’t change it. I tried googling about using PICs with TL866 to see if my assumption was correct but I couldn’t find any mention of handling the OSCCAL value with a TL866CS/A and plenty of people recommending it for PIC programming.

Because the functional Mayumi chip was done the exact same way I assumed that confirms that it did preserve the OSCCAL value but, of course, it is a Mayumi and it sounds like they may still work even without that. Doesn’t really explain why one worked and another didn’t despite both verifying, but since others have reported more trouble using 12F chips instead of the 12C chips, that may already explain this.

I do have some old serial port programmer I used to use for programming PICs for Wii in 2007 so I may break that out if I find that the OSCCAL value has anything to do with it.

Haven’t had the time to move the non-working Mayumi to a PM-41 (2) (A) board just yet to see if it works in the exact same scenario as the other one, so it’s still in the PM-41 (A) board for now. If it does work in the PM-41 (2) (A) board then I feel that I should socket the PM-41 (A) board and cut a hole in the shield for future testing to avoid having to repeat the installation several times as I’ve done here.

 

12f chips work fine.

Ive sold a lot, never had one back.

Ive had 1 12f chip not work in all my years and that's likely just a dead chip. My modern expensive programmer is much better at picking up defective chips than what I used back when I had that one issue. I just throw away chips that fail, which is happens every now and then.

Maybe your issue is just that.

 

I use a TL866 and have programmed over 100 SOIC 12C508As without issues besides a couple failing halfway through that was likely due to my SOIC clip coming loose. I used to use an old Willem years ago (which is what you're probably referring to "serial programmer" (think it was parallel) that wasn't nearly as reliable and a K150. TL866 should be fine I'd say.

 

I never really meant to have the conversation here and was just marveling at the possible relevance of something I didn't remember saying, so I've bumped my other thread specific to this issue with an update

Well, it looks like it is the 12F683/12F675/12F629 port at fault. 12F629 works with the ported HEX on multiple PM-41 (2) (A) boards I tested and it fails on multiple PM-41 (A) boards. I'll be reporting it in the thread regarding the port if it hasn't been mentioned there already (haven't read through it yet).

Guess I should like the gallery from my own testing instead of just using Voultar's video.
https://imgur.com/a/GQ2fN49

Curious: Do you usually install with all 8 wires? No idea if it's a legit concern or not, but here is one of the places I heard it:
https://quade.co/ps1-modchip-guide/mayumi-v4/

Figured there might be some truth to it when Voultar said "Always Mayumi" in the comments to that same video from earlier, but he didn't say why despite people asking. Makes me wonder if he's just operating on the same assumption. I kinda figured there had to be a reason people would want to do more work for a Mayumi and that seemed to be one until you guys told me otherwise.

Well, the same chips worked fine in PM-41 (2) (A) boards, so it's gotta be the ported HEX at fault. 12C508A Mayumi worked great in the same boards 12F629 Mayumi failed. I think you were right to question the 12F683/12F675/12F629 Mayumi port earlier!

Thanks for the TL866 anecdote. It's reassuring! I take it that it preserves OSCCAL for you automatically? For me, it's grayed out and I don't see a way to even read it. Everything I saw when searching for PIC + TL866 guidelines was praising it as one of the best programmers to use for PICs.

The one I used to use was definitely serial because I remember having to set the COM port and baud rate. IIRC, it was a JDM design that many people were using for WiiFree and YAOSM at the time. I recall having to use it at work because none of my PCs at home still had a serial port! I eventually got a legacy Toshiba Libretto 110ct Pentium 233 laptop + dock to keep around for this kind of thing (netbook-sized retro PC). It also comes in handy for old parallel port hardware, like Bung V64, V64jr, GB Xchanger, etc.

FYI: There's a great guide on AtariAge for converting the TL866CS to the TL866A if you want ICSP. There was a recent issue with a software update reverting the FW but I believe they already found a long-term fix. I just never updated.