Thank you for the reply. While doing the first test you suggested (test ground port and ground on plug) the numbers go from 0.6 all way up to 250.0 I can’t get it to settle on a value. View attachment 273849View attachment 273850View attachment 273851View attachment 273852

The last test that you suggested, testing the voltage on the positive ,negative and ground terminals all passed . I had correct voltage on positive to negative and close to zero voltage on positive to ground and negative to ground.

 

If I wanted an earth ground for a different +volt circuit later on I would use the +terminal and the GND terminal on my PSU, and leave out the -terminal?

On most power supplies that have a ground terminal, that ties to the green wire in the line cord, and the ground pin on the power plug. So usually it is not connected to either output post. So you would connect to the + and - output terminals and leave the earth ground terminal open.

 

Good to hear that you did the ground test.

I would not be comfortable with those results. I would expect close to zero ohms in the ground test.

I would unplug the PSU. Open the unit and examine the wiring, both visually and with the ohmmeter. I would expect to see a direct connection from the green grounding wire to any metal chassis and to the front panel GND post.

No ifs, ands, buts, or inconsistent readings.

The last time I purchased 15 PSUs I opened them for inspection and discovered that the LINE and NEUTRAL cables in the power cord were interchanged. The power cords were promptly discarded and replaced.

 

Good to hear that you did the ground test.

I would not be comfortable with those results. I would expect close to zero ohms in the ground test.

I would unplug the PSU. Open the unit and examine the wiring, both visually and with the ohmmeter. I would expect to see a direct connection from the green grounding wire to any metal chassis and to the front panel GND post.

No ifs, ands, buts, or inconsistent readings.

The last time I purchased 15 PSUs I opened them for inspection and discovered that the LINE and NEUTRAL cables in the power cord were interchanged. The power cords were promptly discarded and replaced.

I ordered a replacement PSU I will pop it open and add some photos of the electro-guts when it arrives.

 

I ordered a replacement PSU I will pop it open and add some photos of the electro-guts when it arrives.

Here’s the inside of the PSU.

 

Here’s the inside of the PSU.
View attachment 274006View attachment 274007View attachment 274008View attachment 274009

Let me know if the photos aren’t helpful or there is another angle you would like to see.

Also I ran the floating ground test again on this one and I got 1-3 ohms on the ground pin to the banana pin. For the power test I set it to 9 V and my multimeter said it was putting out 9.2 volts. Is that acceptable, or should it be right on 9 volts. Thanks again for the time!

 

Good to hear that you did the ground test.

I would not be comfortable with those results. I would expect close to zero ohms in the ground test.

I would unplug the PSU. Open the unit and examine the wiring, both visually and with the ohmmeter. I would expect to see a direct connection from the green grounding wire to any metal chassis and to the front panel GND post.

No ifs, ands, buts, or inconsistent readings.

The last time I purchased 15 PSUs I opened them for inspection and discovered that the LINE and NEUTRAL cables in the power cord were interchanged. The power cords were promptly discarded and replaced.

Meant to reply to your comment so you get the notification , think I kept replying to myself…

 

A couple of questions... Does it have a 3-prong cord set plug? Does it have any approval agency stickers, UL, CE, IEC. etc.?
I assume this may be the back of the 3-prong cord set socket? I'm a bit colorblind but is the center wire green?

 

Get your DMM and set it to the lowest resistance or continuity measurement.

Check the resistance from the ground prong of the AC power cord to the green wire on the back of the AC receptacle. Continue on to the green/yellow wire and the GND post on the front panel, as well as any of the screw holes on the metal chassis.

You ought to be measuring close to 0 ohms every time.

 

A couple of questions... Does it have a 3-prong cord set plug? Does it have any approval agency stickers, UL, CE, IEC. etc.?
View attachment 274012 I assume this may be the back of the 3-prong cord set socket? I'm a bit colorblind but is the center wire green?

Yes the center wire is green and runs to a metal screw in the chassis. The same for the ground terminal banana plug on the front. I see a CE on the back of the machine and the power cord.

 

Get your DMM and set it to the lowest resistance or continuity measurement.

Check the resistance from the ground prong of the AC power cord to the green wire on the back of the AC receptacle. Continue on to the green/yellow wire and the GND post on the front panel, as well as any of the screw holes on the metal chassis.

You ought to be measuring close to 0 ohms every time.

Like this?

 

No. Definitely not.
Unplug the power cable from the wall.
Plug the power cable in the proper manner into the back of the PSU.

 

hi bb,
Using a Test Meter, set for LOW Resistance/Ohms, measure the resistance between the two points indicated in this image.

Checking your other images, I would expect the ohms value will be close to Zero Ohms

Post your results.

E