Posts by tomxp411

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Don't Panic. Please wash hands.

    Jens, I finally got the system to glitch again: I am starting to think the VIC is the issue, here. When the system finally glitched, the VIC chip was too hot to touch. Both the PLL chip and the FPGA were no warmer than any other time.

    So honestly, I think this is mostly a case of heat buildup from the location of the VIC under the keyboard. So at this point, rather than blame this on an electrical fault with the Reloaded board, I'm thinking this is an issue caused by an overheating video chip. I don't think there's anything you can be expected to do about an overheating VIC, and I'm not using the system now anyway, since my Ultimate got here. I'll probably just end up selling off the parts so other people can resurrect their failed systems. =)

    Also, your explanation about the power issue with the WiModem has convinced me that the WiModem just isn't compatible, and so I'm going to try to get an RR-Net on my Ultimate instead.

    So at this point, I don't need to pursue this any further. Thank you. :)

    So I put my Mk2 in a case today to test it, before sending it off to you, and of course it's stopped doing it now that the weather is cooled off. It will do this in 10 minutes on an 85 degree (30c) day, but now that it's below 70 (21c), the board is staying cool enough that it won't fail. Right now, I've got the system just running a BASIC program to let it repro the problem.

    I did get it to glitch once, but a power cycle fixed it, and it hasn't glitched again. It's a little frustrating that the problem is this temperature sensitive; considering the cost of shipping, I'd like to make this 100% reproducible before I send the board off.

    Okay. I will ship it with my NTSC VIC installed. It might be a day or two before I can get everything in the mail; I haven't shipped internationally before, so I need to go down to the post office and find out how to do that - and I can only do that on Friday or Saturday.

    Also, it's worth noting that this only happens when the board gets warm. Sitting out on a test bench in an air conditioned room, there's just enough air circulation to keep the problem from happening. Also, as I noted in our prior email, my HDMI converter is actually able to recover the video sync., but my NTSC/PAL monitor does not.

    So the actual failure is easy to miss with good display hardware. I didn't even know anything was wrong until I took the computer and my 1702 monitor out for an event, and the display broke up in the middle of a demo.

    I have used several power supplies with mine, so I am certain it's not a power issue; what convinced me was when I hooked it up to my Wescom 8 amp test bench power supply and had the same problems. =)

    I've actually got a lot of power-related problems with my board: when I use the Ultimate II+, I need to attach a USB power adapter, or the U2 is very unstable. Likewise, when I use Jim Drew's WiModem, the video glitches - a lot. And when I try to run the U2, an SD2IEC, and the WiModem all at the same time, one of the three things simply won't boot properly.) (These all work together just fine on my 64C, so this seems to be a Reloaded problem.)

    I should also note that this doesn't happen when the board is out in the open. It does need to heat up a little bit to have the problem happen.

    Since my Reloaded isn't installed right now, I can ship it back. I just need the shipping information. I can't really ship the power supply, since I use it for other things.

    Should I ship it with the chips installed, so you can use those to help reproduce and/or isolate the problem?

    I've been in e-mail contact with at least one person in august, and this has not been forgotten (tomxp411, that might have been you). I yet have to reproduce the problem here, as I currently believe it to be an edge case that can be fixed with a singla resistor value change.

    I confirm that cases like this will be handled under warranty.


    Thanks, Jens. Yes, that was me. I have also been a bit busy, with the kid going back to school and life in general.

    I have basically the same issue. Using a PAL VIC chip seems to have no problems. The issue there is I have to use a PAL compatible monitor, and those aren't particularly common in the US.

    I chatted back and forth with Jens via email, and he concluded that something in the NTSC timing circuitry is having trouble.

    From what I can tell, it goes something like this: there are two clocks on the Reloaded motherboard: the NTSC and the PAL clock. They apparently both always operate, and there's a component on the board that switches back and forth. So, in my case, one of the components involved in the NTSC clock generation is failing after it gets warm, but the equivalent PAL component is not.

    Since the clock also generates timing signals for the CIA chips, and the CIAs are used for the serial port to talk to the floppy drive, I found that fast loaders were also affected by this; the one built into the Final Cartridge caused data corruption when I saved files to disk. I was using TFC to write some BASIC programs at the time, so I lost several hours worth of work. (I did save often, but didn't verify the saved files, and all the saves were corrupt.)

    At Jens's advice, I took the top off of my 64C case and touched the different chips to see if any were getting hot or maybe had cold solder joint issues. When I touched U23, the image changed. Moving my finger around caused the image to change on the screen, and touching it with a non-conductive object had no effect - so it was my body's capacitance, not a loose electrical contact, altering the image.

    So at this point, i believe my Mk2 has a manufacturer's defect. I need to get back together with Jens by email and see what I can do about a replacement.