Need help Gw instek 1850d psu weird display

[justin55162000]

I am a newbie of electronic, sorry for my poor knowledge.
I recently pick up a Gw instek gps-1850d psu, but the display read "1." as the photo, when nothing is plugged in.
And when start the machine, it have some noise, I wonder if that's normal.
Is that possible to be fixed?

[JFJ]

Might the power supply be in slave mode? For normal operation, the rear panel slider switch should be set in the 'MASTER' position.

[justin55162000]

Thanks for your reply, but I have doubled check that I have chosen the master mode.

[singapol]

GW Instek service mauals are hard to come by...At leat there is the user manual:

Instruction manual:
http://assets.tequipment.net/assets/1/26/Documents/GPS-Small-series_manual.pdf

Not the actual service manual but at least you can have an idea of how a similar power supply is constructed
with schematics. BTW there is a block diagram of GPS1850D in the user manual which is similar to GPD3303S.

GDP3303 service manual:
http://www.eltest.hu/pdf/GPD3303SM.pdf

Good luck. You need to open up the box to investigate.