How to test a Welltronics 24V 5A adapter

My Hazro IPS monitor (2008) doesn't always power up, and sometimes when it does the screen is red or blue. Recycling power usually fixes it though.

I wonder if it is the power supply which is a Welltronics WTS-2405 (120W, 5A)

It has a round output connector (a bit like s-video) with four pins arranged as four corners of a square with the

2 bottom pins slightly further apart.

I tried measuring the voltage on the pins but get zero volts. This might be because it is not connected to a load though. How do I test it to make sure it is supplying 24V ?

If I knew that the PS was at fault I would get another since it seems to be a common part for older laptops too, but if the monitor is faulty, then I won't bother.

Andrew

I had a monitor like that, whose adapter failed. I bought another one and it didn't work. It turned out there were two different pinouts. The adapter commons two pins for +24V and two pins for 0V, but one adapter had the two +24V pins horizontal as you look at the socket, and the other had the left half be +24V and the right half ground. I opened up the new adapter, unsoldered the cable (which only had two wires) and soldered in the cable from the dead adapter. Then it worked.

Recently, I took the monitor out of storage and powered it up. There was a crack and the magic smoke came out - scorch marks on the socket. I must have either mixed up the PSU for another, or plugged in the adapter in the wrong orientation somehow. Anyway, it didn't work after that. It was a terrible monitor so not worth further repairing.

The power adapters are just simple +24V, so if it has no voltage I expect it's a bad adapter. Although be sure to probe all combinations of the plug in case you have the same issue I did (my monitor was a ~2010-12 import from Korea made by Shimian - it was a very good spec for the money in its day but not by today's standards).

Theo