Indivision AGA MK3 for A1200

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Don't Panic. Please wash hands.
  • I seem to have an intermittent problem with the picture breaking up and flickering. It appears to be heat or physical board related, if I leave the machine on more than 2/3 minutes the Amiga graphics start to flicker, though the OSD is stable. It is physically impossible to get the PLCC socket to sit flat on the motherboard because R261A fouls the socket, the cutout made in the socket is nothing like large or deep enough. I can't just leave the top off the machine and no matter how many times I remove the board and refit it, this problem won't resolve. Any hints?

  • It is physically impossible to get the PLCC socket to sit flat on the motherboard because R261A fouls the socket, the cutout made in the socket is nothing like large or deep enough.

    Can you please take a picture of that and upload it here? You may have a variant that requires more space.


    Also, please make sure to use the latest core, so temperature-dependent timing drift is properly taken care of. There has been an update to the config tool, which includes the latest core just yesterday (see Wiki).

  • Hi Jens,


    picture can be found here: https://imgur.com/VUmzmZ5


    it's the edge of the resistor closest to Lisa which is just catching on the socket. I am OK at SMT rework, I can have a go at physically moving the resistor outwards by a millimeter, that would probably be just enough. I am not sure you could take much more material off the PLCC socket without damaging the pins. I guess you put them on a mill before soldering.


    Regards,


    Gavin.

  • I guess you put them on a mill before soldering.

    It's a CNC mill, so precision is very high. However, you're right that we can't take much more material out of the socket, as it would be weakened too much.


    What I assume has happened on your board is that both the resistor and the Lisa chip are placed slightly out of tolerance, so both are a bit too close to each other. I doubt that a full mm will be required - from what I can see on the picture, it's a few tenths of a millimeter that the resistor should more.


    However, before you start soldering, please run the firmware update first. The V1.3 tool contains the latest core, and that does wonders in terms of compensating temperature drift.

  • Great thanks, got the new config tool on, firmware upgraded and have moved the resistor and the fit looks better now. Will leave it running a few hours and see what happens. Thanks for your help!

  • It's a standard, heavy brick power supply although oddly I have just looked at the label and it says it's a 25W supply for an A600. The only other thing I have in the system is a 4GB CF card as my hard drive. I have an external floppy enclosure with a Gotek in it, but the graphics still misbehave whether that it plugged in or not.

  • I don't think it's the power supply. If I push on the Indivision, the flickering stops, as soon as I remove pressure, it starts again. It's like there is a bad connection on the PCB that moves once it's heated up. When I press on the board, it doesn't move against Lisa at all or shift further down.

  • If I push on the Indivision, the flickering stops, as soon as I remove pressure, it starts again. It's like there is a bad connection on the PCB that moves once it's heated up. When I press on the board, it doesn't move against Lisa at all or shift further down.

    This is a hint at a cold solder joint between Lisa and the main board. Most of the time, such a cold solder joint doesn't do much, but with a product plugged on top of the chip, the pins of Lisa will of course move by a fraction of a millimeter, and a cold solder joint will then take effect.


    I managed to take a picture of such a cold solder joint quite a few years ago when my first A600 accelerator came out, but I need to dig deeper where that could be. It's not in the ACA630 project directory... Please remove the flicker fixer and take a very close look at the area where the pins of Lisa are soldered; you are looking for a tiny crack in the heel of the solder, most likely on one of the corner pins. Simply adding a but of flux and re-heating that solder joint for a split second already does the trick.

  • Hi Jens.

    I know HDMI audio is not and advertised feature, I know it was announced as experimental, but I and some other Amiga users at a Telegram Spanish Amiga group wanted to know if it worked or not, so it was the first thing I tried after installing the Indivision:


    https://youtu.be/3ac635dvZTY

    It worked right away, same machine, same monitor. I think the only differences between that try and the one with the same test failing were ticking On and then OFF the "DVI mode" and maybe the screenmode/VGA mode combination (I think first try was made on DblPal HiRes NonFlicker screenmode, can't remember the VGA mode). As you can see at the OSD in the image I sent in the failed audio test, the VGA mode was "EDID 1280x1024@60" for a "PRE 1024x768 HiGFX" screenmode, far below max monitor resolution. I will try again with a lower resolution screenmode.


    Regarding my Dell monitor and its pixel clock at its higher resolution, 1920x1200@60 requires only 154MHz, not 190, at least according to its user manual:


    so I think the Indivision MK3 can handle it, right? In fact, I have re-tried again with my 2015 MacBookPro and it detects all screenmodes, including HDMI ones (1080p, 1080i):




    I know it's a more modern technology than a 30 years old Amiga trying to output video and audio through HDMI (which is an extraordinary achievement, I must say), I only included it just to show you that the monitor works OK with other computers though HDMI.


    BTW, talking of age, this Dell is from 2010, maybe it has something to do the HDMI specification? :/


    I will try with another monitor (the only other one I have belongs to the same family, a Dell 2711, same specs, same inputs, just a bigger screen and from 2011).

    If there's any other test I can do regarding audio, just ask. I will keep trying VGA/Test modes combinations, let's see if that can be solved, I would like to have both audio and video through HDMI. ;)


    Saluditos,


    Ferrán.

  • This is a hint at a cold solder joint between Lisa and the main board. Most of the time, such a cold solder joint doesn't do much, but with a product plugged on top of the chip, the pins of Lisa will of course move by a fraction of a millimeter, and a cold solder joint will then take effect.


    I managed to take a picture of such a cold solder joint quite a few years ago when my first A600 accelerator came out, but I need to dig deeper where that could be. It's not in the ACA630 project directory... Please remove the flicker fixer and take a very close look at the area where the pins of Lisa are soldered; you are looking for a tiny crack in the heel of the solder, most likely on one of the corner pins. Simply adding a but of flux and re-heating that solder joint for a split second already does the trick.

    I've just reflowed every leg on Lisa, got everything refitted and the picture is stable for now. I will leave it for a while and see what happens when it heats back up again.

  • so I think the Indivision MK3 can handle it, right?

    Yes and no - the 154MHz pixel clock is definitely within spec, but it requires vertical sync to be negative (probably to tell the monitor that it should switch to a different input mode). At this point, we have trouble outputting negative vertical sync, as the HDMI encoder chip inverts it back to positive sync, no matter what we choose. There is a support case open with the chip manufacturer, but it is *very* difficult to deal with this company. So far, we've fixed more problems with this chip with try-and-error and by ignoring the datasheet, as that's not only incomplete, but also incorrect in many places. We still hope for proper answers from Chrontel :-)

    I would like to have both audio and video through HDMI.

    Rest assured that this is our ultimate goal as well. However, there's more development to be done (both on the FPGA and the config tool side), and we also need more experience in the field with monitors, EDID data and the capability to play back audio in different sampling frequencies. So the current message remains: If audio over HDMI is a key feature, please do NOT buy just yet. Better wait until we say "this is as good as we can get it", then judge for yourself if it's enough for you.


    Our primary reason to choose HDMI over DVI was that most HDMI monitors support 50Hz modes, and those are silky-smooth, tearing-free and lag-free if you use the "Auto+VSync" modes in the config tool. To me, these modes are the holy grail of demonstrating what your favourite computer can do with 35-year old technology. No emulator comes close to that experience.

  • My money is on the BGA having at least one bad ball...

    That would be a "first" - we have so many Indivision ECS V2 in the field that never had any trouble - granted, it's a smaller FPGA die-wise, but the same BGA-256 package - and the same BGA package is used in Chameleon V2 with a much larger die (25k LEs). All have been assembled by the same service company - a very reliable one with lots of experience in the industry, up-to-date machines and very experienced personnel.


    Anyway, if you believe it's that, it would be a warranty case and we need to look at the unit here. Please send it for a check.


    EDIT: Before you pack it up, please try the latest config tool V1.4 with corrected EDID evaluation (see Wiki).