Axiomet 3005D PSU earth connected to positive output

[aandras]

Hi,

i have one of these devices: https://en.axiomet.eu/gb/en/product/axiomet/laboratory-power-supplies/ax-3005d/100165/
Yesterday - during some testing - i have just realised, that the earth banana plug (green) and the the red positive output plugs are directly connected.
Which means that the positive output is connected to AC mains earth.

I wonder if that is a common thing in PSU-s or am I facing a faulty device?

thank you,
András

[siggi]

Having the ground terminal shorted to either output terminal seems unreasonable. Typically you'd want a lab PSU to be floating, with the option of tying either terminal to ground. Typically there'll be a spec as to how far away from ground you can float the supply, but there's no such spec in the manual.

How did you determine that it's shorted GND to positive?

[aandras]

Using my multimetermeter, connected to the grean and the red terminal, having the AC plug conneted and then disconnected too.
If the AC plug is conneted, than there is a short between the red + teminal and the oscilloscope's probe ground (both connected to mains, otherwise no other connection between the two instruments).

Actually i was trying to measure with my scope a circuit that i powered with this PSU and there were some uncomfortable issues (almost smoke),
that lead me to investigate the situation and finding this strange short.

[Gyro]

No that's not normal. It has a fault. There should be no connection between the +Ve output terminal and chassis.

Only a wild guess, but it may be that the series pass transistor is shorted to the case.

[aandras]

Thank you for the answers. I decided to look inside and i have found the cause. One (actually more) solder points on the PCB are simply too large,
and if the chassis is mounted they are touching each other. The space that they designed between the back of PCB and the metal case is too narrow.
First picture, left hand side solder, that is connected to +ve output as are some of the solder points on the second picture.