I don’t remember reading a post where you responded to this.
If you did not read, measure, high voltage, or any voltage... Question... Is the SMPS 120Vac plug in blades the same width or is one wider than the other? Therein polarized. If both blades are the same reverse the SMPS 180 degrees in the receptacle and perform the test for high voltage again.
That is from the long winding thread I posted yesterday.
.
One other thing I didn’t think about yesterday. The tests for the SMPS I had you do for checking for AC mains high voltage on the output side of SMPS were unloaded.
I don’t know what I was thinking yesterday... I should of had you do the tests with the phono preamp connected to the SMPS. Therein the connected load. Likely a defective connected load that might be overloading the SMPS. A real world test...
Probably also should have had you use the wall outlet that the SMPS is normally plugged into. IF, one of the blades is not polarized, therein it could be plugged in either way, it would be plugged in the direction that caused the electrical spark fault event.
.
IF you want to try the test again.
Test procedure is a little different than yesterday.
You will still use the OEM 3 wire power cord to connect one of the mm test lead probes to the wall EGC. ( an extension of the probe lead)
1) Set up for the test.
Before the SMPS output power cord connector is plugged into the phono preamp.
Connect an IC (interconnect cable) into one of the RCA output jacks on the preamp. Extend the other end of the IC so it will be easy for you to touch the other test lead probe of the mm to the outer ground shell of the IC RCA plug.
2) insert the mm black test lead probe into the female EGC ground contact of the plugged in OEM power cord.
3) Set mm to "V". (mm will default to V AC.)
4) Plug SMPS output power cord connector into phono preamp. (Blue light starts doing its’ thing. Preamp has DC power. SMPS has a load on its’ output)
5) Touch mm test lead probe to the outer ground shell of the IC RCA plug.
What voltage is measured, displayed, on the mm? No need to check for LoZ voltage. The connected load of the preamp is more than enough load. LoZ would only add a small additional load.
6) Check again for a voltage reading after the blue light on the front of the preamp is no longer lit for any difference of voltage measured.
7) Just to cover all the bases... Repeat the test measuring for DC voltage. You probably should let the phono preamp do a reset by disconnecting the SMPS power cord plug from the preamp. Just trying to cover all the bases.
Post back your results.
.