Problems detecting VIC 6567R8

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Don't Panic. Please wash hands.

    Hi,


    I’m seeing an mis-detection when running with a VIC 6567R8 IC installed in the MK2 board — it shows up as an 8000-series chip. If I drop into the factory mode and switch to providing the 12V supply all works fine. Any suggestions so this doesn’t require the manual intervention? Happy to help debug further.


    Thanks,


    —Patrick

    The power supply is a Triad 12V, 3A. Model WSU120-3000. The ripple is 150mV so not ideal based on your recommend specs for video and audio quality but it is the only 12V w/ >= 2A that I had available at the moment.


    Chip detection reports:


    VIC-II: 8562 <B3 00 9880 NTSC>

    SID 1 : 8580 <DC 00>

    SID 2: 8580 <DD 00>

    CPU : PHI2 OK (045A)

    MCU : 20180227

    Yes, I have good multimeter. I will check this evening and report back. Thanks.


    I managed to get a quick reading: I see 12.2V on the rail at the board-side of the power jack (powered up), which is basically the same as the power supply reads without a connection. Not surprisingly, I see 5.0V at pin 13 on the VIC-II (which matches the mis-detection). Is there a specific spot I should check further in on the board for the detection logic?


    Thanks,


    —Patrick

    I did a bit more troubleshooting today. I turns out that I happened to have another 6567R8 in a working C64 for testing. It is detected by the MK2 and the chip that was in the MK2 works fine in the C64. So, there is an obvious solution path here. :)


    Any details about the potential problems with the troublesome chip? Does the detection mechanism suggest something is potentially failing in this particular VIC-II?


    Thanks.


    —Patrick

    With 12.2V, the diode near the plug (D8) may get hot already, as it should burn anything above 12V. The 12V rail should be precise for proper recognition, otherwise the variations from chip to chip may lead to a wrong identification.


    So no, I don't think that anything is failing, but it's a variation from chip to chip. Pretty normal back in the days.


    Jens

    I have issues with my MkII Reloaded consistently starting up consistently with a VIC-II R8. In terminal, the board is inconsistently recognizing the R8 6567. I am getting 12.11v testing power output under load. I am using whatever recommended PS I bought or received with the board. Is it possible that a different PS will help this problem, or do I need to try other R8s (I tried one and it didn't change anything) or find myself an R9? Buying another chip is less desirable (unless I can find one in my parts bin) since these MOS custom chips have gotten quite expensive.


    If a different PS will help, can you Jens recommend one on Amazon (110V)?


    (I connected to terminal at a Commodore group meeting, and doing it again at home, I would need to start from scratch so I would prefer not to).

    The Commodore-branded PSU that we're selling is the only one I'd recommend. I am generally sceptical of anything from Amazon.


    The detection does not find out what revision number the chip is. It only founds out if it's a HMOS (85xx) or an NMOS variant (65xx) and sets the voltage accordingly.


    If you have a 6567 chip and get 12V at the chip, everything is fine. I don't understand the "issue", as you didn't describe what "inconsistently" means.


    Jens

    By inconsistently, I mean when I power on the board, it does not start up the computer consistently. In terminal, when the computer is not starting up, the diagnostic shows that the board is having trouble detecting the 6567. Maybe 1 in 4 tries to power up the computer is successful.

    In terminal it was flickering between 6567 and 8562, it couldn't decide on which it was.


    I broke down and spent $65 (including shipping) on your Commodore power supply for the MK II and the problem seems to have improved. The unit starts up consistently. I'm sure I was following instructions when I bought the unit several years back, in getting an equivalent power supply.


    Attached are the power supply I was using and the Individual Computing power supply.


    The technical data appears correct, but you never know if the manufacturer really fulfills it's own specification. That's why we put all supplier parts through extensive testing, send local persons to the China factory and do further tests that our product liability insurance requires. You might think that this is an unnecessary amount of red tape, but your experience shows that it's totally worth it: Even with the point-of-load regulator on the C64 Reloaded board, quality of input power still plays a huge role.


    Jens