mt777 wrote on 2023-01-23, 14:28:

https://theretroweb.com/motherboards/s/shuttle-hot-419

Problem: voltage regulator is properly set as output is 3V but directly measurement on cpu socket still provides 5V.
Maybe I wrongly check something or source of VCC in socket is somewhere configured?

I don't know what pins you intend to measure. You are at D1 with the positive lead of the meter and at H1 with the negative lead. H1 is GND (aka Vss), which is fine. D1 is the data pin D9. Even for 3.3V processor, the mainboard still uses 5V signalling. That's not an issue for the processor, as the I/O pins are "5V tolerant". This means the processor can properly receive signals up to 5V, but it will only send about 3.3V as "high". That's again not an issue, because the levels of the 486 frontside bus protocol are specified as "TTL compatible", which means that the mainboard has to except everything above 2V as "high".

Your measurements thus do not show a problem, but are also unsuitable to verify the processor operating voltage.

yes, my fault (recognized after posting).
Socket layout is 19x19 where cpu is 17x17. So I used wrong pinouts.
It is fine, 3V