@raz_pl It's the same cycle whether I use the reset switch or the power switch, meaning I need to either power cycle it 3-4 times or reset it 3-4 times (or any combination there of) to get it to POST. After messing with it for more hours tonight I figured in for a penny in for a pound. An eBay …

So I checked the ISA reset line (pin 2 of the ISA slot on the bottom row), it looks normal. It stays low the entire time after the system is powered on, going high only for a millisecond or so as the system powers down. This was the case on attempts when the system both did and did not POST …

Yes, i'll give that a try before I try to remove the 82C206. Rather then make one I just ordered a https://www.amazon.ca/gp/product/B09W3XFSR2 off amazon to make that a little simpler. I'll also take a good look at the pins and traces around the 82C206.

I'm actually starting to suspect the 82C206 on this board. It seems to have everything in common with the unusual behavior: -It handles the power good signal from the power supply, which could explain the strange behavior and difference between power supplies. When the power good is low, all address …

@Horun @chrismeyer6 I've thought about replacing all the tantalums on the board but I have not done it. I may yet give that a shot - it's fairly cheap to try and easy to do and there are not that many. None of them look visibly damaged or burnt and in my experience bad tantalums usually either short …

Sorry I didn't realize I accidentally posted this early version of my thread. I must have hit post instead of preview, the complete post is here: https://www.vogons.org/viewtopic.php?f=46&t=100345 But to answer your question it's a 25MHz CPU, so it's a 50MHz clock oscillator. I was looking at the …

I got this board for free from a guy in town who was downsizing his collection (photos near the bottom). I have put many days of time (and a bit of money in parts) into this thing and I haven't been able to get it to boot consistently on the first try. Here's what it does: After it has been off for …

Posted by mistake, correct post is here: Trying to save an ASUS ISA-386U3Q, ideas appreciated.

Considering there's xt-ide firmware files for XT, AT & 386, which one were you using ? I was using the AT one, but actually I should have been using the 386 one given this is a 486. I was just thinking today maybe it was that simple. I'm itching to try it if only I had a working eeprom.... I also …

What CDROM driver are you using? I don't see it, if it's SBIDE.SYS it might be getting confused between seeing the SB card and thinking due to BIOS it's onboard secondary, while something like OAKCD.sys doesn't give a crap whether it's on a SB card or not. It was VIDE-CDD.SYS, I will admit I …

Well, silly me for not reading the OPs actual post before commenting :-p hpxca, what are your system bios hdd settings set for ? WRT the shadowing, it's likely the whole segment, ie 64K, simplest test would be a program that times reads from those memory locations which you run twice, once without …

Hmm, both of those threads are very interesting indeed. I may try to mess around with the control block address for a bit, but I have no idea how to figure out their location beyond a guess-and-test. There may be a delay for me to do further testing on this though. I accidentally plugged that card …

Dear Vogons Folks, I was building a 486 DX2-66 and I ran into the common 504MB BIOS limitation with respect drive space. I tried EZRAID (DDO) to get around it and while it works just fine I wanted to mess around with XT-IDE as well. I purchased an ISA ROM card..this one => https://www.ebay.ca/itm/ …

Here's the photos of mine, much better then the image I posted originally. It's not entirely what I thought after I looked up the chips. The WDC WD37C65CJM is just your average floppy controller and the Ti TL16C452FN is a dual UART + Centronix Parallel port chip. https://www.sejr.ca/erik/pages/ …

https://drive.google.com/uc?export=download&id=1G84aRCFjq_q9hRgLLQSfqcpMiJhMqQlZ It looks like the above image (this is the same card, but the image is borrowed from the one in York Universities collection). I have a working example of one of these, it appears to be a single-board computer used as …

jakethompson1 wrote on 2024-01-01, 04:01: (after DEVICE=C:\DOS\HIMEM.SYS) and […] Show full quote Copy code to clipboard 1 DEVICE=C:\DOS\EMM386.EXE NOEMS (after DEVICE=C:\DOS\HIMEM.SYS) and Copy code to clipboard 1 DOS=HIGH,UMB in config.sys If you later need EMS, come back and revisit Thanks so …

Hello, I am hoping for some help from folks on the board here. I am old enough to have used/played games on an 80486 but young enough to have never built one (I had one as a kid). I decided to put one together and picked up a bunch of parts from a local guy with A LOT of old stuff in his basement. …