First post, by Sedrosken
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Back again with my GA-486VM based 486 machine. I've overcome the hurdles of replacing the CMOS battery -- soldered an old CD-audio header with thick wires to a 3xAA holder, works great, RTC runs accurate as my watch that can sync to the atomic clock radio broadcasts -- and the IO card, which I eventually decided on an ISA WinBond-based controller, the PTI-237W, after a bad experience with the DC-2000VL that I decided on in my last thread. It makes my machine hard lock up about a minute to five minutes after boot. That, and I came to the conclusion that as long as you have a good ISA IO controller, you're not going to notice much of a difference vs. VLB but you'll definitely notice increased stability since the ISA bus runs pretty standard at 8.33-11MHz. At a 40MHz bus it's just not worth the trial, error, and buying new cards cycle that I've seemed to fall into. And no, before you ask, it wasn't stable at 33MHz either. Same song different verse -- hard lock after about five minutes with the DC-2000VL. And I know this machine can be stable because it was fine with the UMC VLB super IO I had before.
But enough about that, as like I said, I've solved those issues. I'm even having a friend burn a copy of the XT-IDE Universal 386+ BIOS to an EPROM for me to stick in my 3C-509B so I don't need to keep using Ontrack, which mangles the partitions enough on my SD cards that my Linux laptop and desktop can't mount the partitions (but they know they're there). I configured it in DOSBox for my machine, sent him the image it spit out, and he's going to burn a couple 28C64s with it for me.
Now, I'd already bought a TrinityWorks Am5x86 upgrade, but as it turns out one of the pins broke off, and I think I'm dealing with bad solder joints in the interposer, since after fixing the broken pin and verifying continuity I got it to pass POST all of twice and now it refuses no matter what I set the DIP switches on it to. The seller sold it as a collectable, not necessarily a working CPU, so I don't have any recourse on this... I'm just ready to leave this behind. From what I understand, my options are to overclock my DX2 to 80MHz (seems to get through everything but Quake), use a voltage adapter that's fairly rare and expensive on a "normal" DX4 or 5x86 (hopefully figuring out how to set the multiplier beyond the 2x my board supports) or using a DX4 OverDrive. Said OverDrive would be overclocked to 120MHz, since I'm not giving up the 40MHz bus (my video card performs even better on that). Plus, the OverDrives, while available, are rather ridiculously expensive in my opinion -- I got the 5x86 for about fifty bucks, the minimum listing for the DX4 on eBay is 70 bucks out of Taiwan.
Does anyone have any other suggestions? I'd keep the DX2 at 80 but it not even launching Quake at that speed (bad surface extents) suggests it's not as stable as I'd like it to be, though at that speed it can finally play MP3s and it gets a much better score in Doom (30.3FPS vs 23.7). I wouldn't be opposed to, if I found a voltage adapter, using an AMD DX2-80 instead for stability since 80MHz seems like about what I need... Use of other machines isn't really an option, I sold off my PPro stuff a while back and my machine choice is limited to this and an Athlon XP WinXP rig.
Nanto: H61H2-AM3, 4GB, GTS250 1GB, SB0730, 512GB SSD, XP USP4
Rithwic: EP-61BXM-A, Celeron 300A@450, 768MB, GF2MX400/V2, YMF744, 128GB SD2IDE, 98SE (Kex)
Cragstone: Alaris Cougar, 486BL2-66, 16MB, GD5428 VLB, CT2800, 16GB SD2IDE, 95CNOIE