I'll probably have to take off the uppermost SIMM socket. I can see corroded traces underneath. And although I have traced it all out and everything checks out, there could be still sufficient unneutralized base under there that provides enough of a current path to throw off the chipset. Will try rinsing it again with vinegar and alcohol. If that doesn't help, I'll have to take off the socket. But that's going to be really ugly, judging from my experience with the NAND gate.
Bun's Lab
I'll probably have to take off the uppermost SIMM socket. I can see corroded traces underneath. And although I have traced it all out and everything checks out, there could be still sufficient unneutralized base under there that provides enough of a current…
I washed it, dried it thoroughly, no dice. I also mapped out the Data lines to the chipset now, because these are the only traces that could still be affected. Everything checks out.
I'm beginning to suspect a broken chipset. Cooling it down produces different codes
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Sometimes it does two or three passes before it arrives at 1312 and hangs. This behavior depends on the temperature of the IC.
I'll call it quits for today. Thinking about tossing it into the parts bin.
I'll call it quits for today. Thinking about tossing it into the parts bin.
It's sporting an 8 bit Ethernet card, an 8 bit Aztech SoundGalaxy soundcard, as well as an XT-IDE setup.
The XT-IDE ROM lives on the network card, it's configured to use a 16 bit IDE card in the XT's 8 bit bus. As long as you use an IDE device capable of 8 bit transfers, such as a CF card, this is perfectly fine and works.
On the right you can see the bare bones IDE card that I use. It was meant to provide a secondary IDE channel for CD-ROM drives in a time when these weren't standard yet. Hence why it has those two chinch connectors. They just route the drive's analog audio out to the back of the PC with no amplification even. There is barely anything on the card except for some buffers and logic.
The IDE bus originally was just the ISA bus in cable form.
On the right you can see the bare bones IDE card that I use. It was meant to provide a secondary IDE channel for CD-ROM drives in a time when these weren't standard yet. Hence why it has those two chinch connectors. They just route the drive's analog audio out to the back of the PC with no amplification even. There is barely anything on the card except for some buffers and logic.
The IDE bus originally was just the ISA bus in cable form.
Bun's Lab
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The clunky 20 Mb MFM drive is deactivated because it's way too loud for my nerves.
Usually the MFM controller card would throw an error, if the hard drive gets no power. However, I found a hidden jumper that was fixed with a jumper wire. I put a jumper header in instead. If unset, the controller too is deactivated. Which makes it possible to leave it in even if unused. Eventually I'll expand that into a switched configuration. Enabling me to turn the MFM portion of the system on and off as I please.
The XT-IDE can happily coexist with the MFM drive.
The XT-IDE can happily coexist with the MFM drive.