Went with dual 1N5408 now, which output 4.2V in idle and fit nicely after removing the heatsink and reattaching it with superglue.
Runs absolutely stable with 24.1fps in Quake_low making it the fastest sub-Socket4 machine of the German DOS community 😀 There's still some room for improvement, as the POD only runs in WT mode on my current board.
Diodes get quite warm, but nothing overly worrying.

Glad to hear it is working out for you. I've done this mode with the double diodes without removing the heatsink, but requires more delicacy.

Very few motherboards work properly with the POD in WB mode, but they do exist however rare.

My POD has been running absolutely rock solid at 100Mhz, thanks to the info in this thread.

Has anyone had any luck with posting at a bus speed setting of 50Mhz?

Would there be a way to get something in between 40-50Mhz , to try and push the speed just a bit higher?

Chadti99 wrote on 2021-01-30, 18:44:

Would there be a way to get something in between 40-50Mhz , to try and push the speed just a bit higher?

Yes, a few have modded the pcchips m571 for 100mhz FSB by tweaking the source on the clock generator

Same could be done to the pll on a 486 or if you have an older board just replace the clock crystal

I think I've seen a few people POST their POD's at 125 MHz (2.5x50), however I don't think any were long-term stable.

Replacing the clock crystal doesn't always work as it messes up the timing of other systems, most notable will be the the floppy controller not working properly.

Thanks guys, always looking for a way to push this system a little bit more.

It was suggested i share these two clean implementations of the final mod design:

This one turned even better:

Full story and details here.

Yes, thank you. A gorgeous mod esp. with the Intel heatsink installed. Were you able to do the mod without removing the re-gluing the heatsink? I found it is just doable without removing the heatsink.

feipoa wrote on 2021-01-31, 00:25:

Replacing the clock crystal doesn't always work as it messes up the timing of other systems, most notable will be the the floppy controller not working properly.

Disable onboard floppy controller, run an ISA floppy card problem solved

rmay635703 wrote on Yesterday, 00:39:

feipoa wrote on 2021-01-31, 00:25:

Replacing the clock crystal doesn't always work as it messes up the timing of other systems, most notable will be the the floppy controller not working properly.

Disable onboard floppy controller, run an ISA floppy card problem solved

It's not very elegant though. But if you are OK with this type of solution, then more power to ya. So what FSB are you using now and is everything else running fine?

Thanks.

The first cpu was modded long ago.
Primary objective was to make it work, anesthetics were secondary.
I will probably redo it for pretty at some point.
Its heatsink has opening at the front which allows to make the mod without removing it.
Currently I use this one because of the better ventilation.
The big fan is noisier, but keeps long term stability in check, especially inside closed case.
The computer is fully equiped and maxed out, so it gets warm inside.

The second modded cpu turned even better.
This time "looks" were in the front seat.
This heatsink model has a grill on top of the elements.
Had to use thin and long soldering hotend, inserted from the inner side to reach the back leg.