Some good news! Those little 8mm self-latching switches I ordered a few posts up (thanks for the idea TheMobRules) were a perfect drop-in replacement for the existing switches on the front of my case. I took a spare jumper wire, soldered one switch to it, plugged it into Reset button, plugged the other into the turbo header, and poof! My reset button becomes a turbo button! Did the same with the power switch coming off my AT-ATX power supply adapter. So now I can close up my case finally. 😀 Power button=power button; reset button=turbo button. Sweet! Still no I/O shield, but I don't care about that, as I can't see it. 😉

Have given that shield some thoughts on how to make.
If you cut out some vinyl/plastic that fits on the outside of a random shield, and bore a hole in the right place?

brostenen wrote:

Have given that shield some thoughts on how to make.
If you cut out some vinyl/plastic that fits on the outside of a random shield, and bore a hole in the right place?

Someone mentioned using clear plastic from something like an ice cream tub lid. That lets you position the hole easy because you can see through it. Then after cutting the hole, either paint it silver or cover it in aluminum foil. I probably won't do this though, because I'm hopeful to come across a real AT 486 case soon (a friend says he may have some NIB in his storage, and I am waiting for him to find time to check).

Just use the clear plastic as a template.

Uhh.... This clear plastic makes me think of a possible way of doing an easter egg artwork kind of thingy. 🤣

Here is the final build.

I forgot to take pics of the switches after I modified them, but basically I cut the green and black wires to remove the big mechanical power switch off of the AT-ATX PSU adapter.

I soldered the green and black wires to the latching power switch.

I used the existing momentary switch as a template. So the green wire went on the upper left pin and the black wire went on the pin right below the green. To orient, there is a little hole on the bottom of the switch. Hold the switch so the hole is at the top. Green is on top left pin, black on the middle left pin. Once the soldering is complete, just replace the existing case switch with the new one. There are two clips on my case that hold it in place.

I did the same thing for the Reset button below the power button. I got a spare jumper wire from another case and soldered to the latching switch in the same orientation (colored wire upper left, white wire middle left). Dropped the switch into the reset button location, plugged the jumper into the turbo switch header on the motherboard.

Edit: just to note, now when you push the power button on the front of the case, the button stays in a recessed position due to it being a latching switch. Same with the reset button. It stays pushed in when you engage turbo.

Polarity won't matter for the switch.

gdjacobs wrote:

Polarity won't matter for the switch.

Good to know. Does it matter which pins? I think they both have to be on the same side but does it matter which of the three pins?

The upper and bottom pins are connected to the middle (common) pin when the switch is either 'in' or 'out' (on a latching switch). The two sides are electically isolated from each other, so you can have one switched between top and bottom on the left side and another switched between top and bottom on the right side.

So for example push and it latches in, top and middle pins are electrically connected, push and it pops back out, bottom and middle pins are electrically connected

Looking good! I'm super jealous of the Pentium MMX machine you have there too!

Nipedley wrote:

The upper and bottom pins are connected to the middle (common) pin when the switch is either 'in' or 'out' (on a latching switch). The two sides are electically isolated from each other, so you can have one switched between top and bottom on the left side and another switched between top and bottom on the right side.

So for example push and it latches in, top and middle pins are electrically connected, push and it pops back out, bottom and middle pins are electrically connected

Looking good! I'm super jealous of the Pentium MMX machine you have there too!

Thanks for the explanation on the switch!

Here's some more photos of the Pentium MMX machine, including some lovely internal shots.
Souped up Packard Bell
I really like having it on my desk with the monitor on top, but it takes up too much room, so I moved it to the floor. 🙁

If you're ever in doubt as to which pins are normally open or normally closed, always have a multimeter around.

h-a-l-9000 wrote:

It's not a grounding problem - at the latest when you tighten the screw for the slot plate it makes contact with the case and thus is grounded. The metal down there is electrically same as the rest of the case.

You have cracked solder joints, broken traces, corroded contacts or something along these lines - the little force caused by the bent plates will put it back to operational state. This is no reliable fix though.

The mainboard or affected expansion card have to be considered trash unless you find and fix the cause.

Well, I started having this issue again, where I'd make an adjustment in the case, and it would stop posting. I thought I'd solved it earlier, then your comments above made me think twice. After about an hour of troubleshooting today, it turns out it was an issue with the IDE cable. I have to master/slave my hdd and optical drive, and the cable I was using was oriented such that I had to twist the middle (slave) connector. Something was going on there, either a bad cable, or intermittent disconnecting when I'd make adjustments in the case. Regardless, I swapped the IDE cable out with one that did not force me to twist the slave connector, and that solved the problem.

I literally spent most of my time making one connection, turning the system on, verifying it posted, turning off, making another connection, etc. I was able to reliably reproduce the issue every time I plugged the IDE cable into the controller card. I'd disconnect, it would post. Reconnect, not post. So hopefully this issue is behind me 100% now!