The most likely reason is that the DX5 has pushed a component (or components) that was marginal, beyond the point where it has failed. I’d focus on measuring voltage rails, specifically around the CPU voltage regulator.

Could be the regulator itself is not working right, or a nearby capacitor has failed and is affecting either peak voltage or ripple.

You say you don’t have the tools or skills, but a basic multimeter and a POST diagnostic card aren’t particularly expensive nor complicated to use, and go hand in hand with running 30+ year old hardware.

Thanks. I appreciate the advice. I'll take look at that. Does anyone provide this type of repair service on retro equipment? Thanks again. -Ger

Any general electronics repairer would be able to replace the components on a 1980s-1990s motherboard, it wouldn’t require particularly specific equipment, just basic soldering/desoldering tools.

Far easier to find someone that can replace what you have already diagnosed than trying to find someone who can diagnose parts that they have likely never seen or used, hence trying to find the fault yourself with basic diagnostics first.

Thanks. -Ger

What are the brand and model of your motherboard?
AMD 5x86/133 is write-back or write-thru capable?

For jumper configuration. Try searching for the motherboard or chipset at https://theretroweb.com/

Thanks - it is an SIS 471 motherboard. I followed the jumper settings both ways - from 486 to 586 and back. Thanks for the help - I hope that I can get it going again. -Ger